Semi-durable Fire Retardant Finishing of Jute Fabric

and its Thermal Behaviour

Prof (Dr) A K Samanta, Fellow

Dr S K Biswas, Non-member
A Bagchi, Member
R Bhattacharyya (Roy), Associate

Bleached jute fabrics have been subjected to treatment with sb( different fire retardant formulations based
on combination of diammonium phosphate (DAP), mixture of borax-boric acid (7:3), tetra-sodium pyro­
phosphate, sodium per-borate with or without DMDHEU (resin) and MgCI2 (catalyst) by pad-dry cure
process for imparting semi-durable fire retardant finish on it. The fire retardant performance of each
formulation investigated and were compared with the same fora commercial fire retardant finishing agent
(Pekoflame DPN) in terms of LOI value, flame spread time, afterglow time, char length and changes in
tenacity, breaking elongation, bending length, flexural rigidity, and surface appearance in terms of K/S
value, whiteness index, yellowness index and brightness index. Most of the fire retardant formulations
showed moderate fire retardant performance showing 27-33 LOI value where highest LOI value (33.0) was
achieved by formulation 5. However, all the above fire retardant finished fabric showed loss ofnearly 15%-
20% of LOI value on soap washing. Loss of tenacity on such fire retardant treatment was around 15%-40%
in different cases. Thermal behaviour by analysis of DSC thermograms, TGA thermograms and thermal
resistivity value (C!o and Tog value) of the experimental fabrics showed that formulation 5 [based on
treatment with mature of 12% sodium perborate 12%, 12% borax plus boric acid (7:3), DAP 4% and 4%
DMDHEU with 1%MgCI2] catalyst gives maximum Clo-Tog values, minimum weight loss during heating at
ambient of 500°C at different temperature zones as well as somewhere a bit early and somewhere a bit
delayed thermal degradation/pyrolysis of major jute constituents showing a different thermal behavior
pattern than control bleached jute fabric.

Keywords: Differential scanning calorimetry, Fire-retardant finish; Jute fabric; Limited oxygen Index, Theimal Insulation value;
Thermo-gravimetric analysis

INTRODUCTION suitable proportion of organo-phosphate compound etc.

Some details are available in review2-3 literature on chemical
There Is high demand for fire-retardant textiles for protection
finishing of jute. Borax-boric acid mixtures have been using
against-catching-fire in variety of end-uses. For jute based
for a long time to impart temporary fire retardancy to jute
fabrics to be used in mines, car upholstery and as
substrate. Some preliminary studies on temporary flame
fumishlng/upholstery in home textiles as well as for kitchen
retardancy of jute has been also reported eariier by other
apron and gloves etc., it needs to be preferably fire resistant
researchers4-5, with the treatment with borax-boric acid/
Cellulosic fabrics can be made fire-resistant by treatment
diammonium phosphate and potassium-sodium tartarate
with different non-durable and durable fire-retardant
(Rochelle salt). Preliminary study of thermal behaviour of
formulations, which are readily available in the literature1.
jute fibre and its components for different chemical
However, for lignocellulosic fabrics, it is necessary to
treatments has been reported7"11 eariier for understanding its
standardize the formulation (recipe) and methods for
thermal degradation behaviour.
application of fire retardant finish separately for jute and jute/
cotton union fabrics. Hence, It may be said that for lingo-cellulosic fibres like jute,
not much work has been done except the works cited above.
Most of the conventional processes found in literature2-5 for
The work done so far on flame retardancy of jute fabric are
obtaining fire retardancy on jute fabnc is based on
mainly temporary type and using only limited number of fire
application of a combination borax and boric acid (7:3) with
retardant chemicals. Hence, in the present study, efforts
were being made to develop semi-durable water based fire
Prof. (Drj A K Samanta, Dr S K Biswas, A Bagchi and
R Bhattacharyya (Roy) are with the Institute of Jute Technology, retardant treatment formulations based on mixtures of two or
35 Ballygunge Circular Road, Kolkata 700 019. three different fire retardants such as Di Ammonium
This paper (modified) was received on August 16, 2010 Written
Phosphate, borax-boric acid, Tetra Sodium Pyrophosphate
discussion on this paper wfll be entertained upto April 30, 2011 and Sodium Perborate in different ratios along with the

18 IE(I) Joumal-TX
crosslinking agent DMDHEU to study the efficacy of the Sodium Perborate-12%
different combined formulation on the flammability and
DAP-4%
related properties of such jute based fabric
DMDHEU-4%(active)
MATERIALS AND METHODS
MgCI2 catalyst- 1%
Fabrics
Formulatlon-6
Conventional H202 bleached plain weave jute fabrics having
63 ends/dm, 59 picks/dm, 220 g/m2 (area density), 195 tex Pecoflame DPN-4%, 8%, 12%, 16%
warp, 214 tex weft were used for the present study.
DAP-4%
Chemicals
DMDHEU-4%(active)
Laboratory reagent grade diammonium phosphate, borax,
boric acid, sodium perborate, tetra-sodium-pyro-phosphate, MgClj catalyst-1 %
and magnesium chloride of E Merck, India, and Pekoflame Testing Procedures
DPN (THPC, ie, Tetra-kis Hydroxy-methyl Phosphonium
Chloride based) and Finsh-KVS (DMDHEU, ie, dimethylol- The bending length of fabric samples was measured as per
di-hydroxy ethylene urea) resin pre condensate from IS-6490-1971 method.
Clariant India were also used. Warp-way breaking tenacity (cN/tex) and the breaking
Methods extension (%) were measured by the ravelled strip method
as per IS-1969-1968 method using I nstron Tensile Tester.
Bleached jute fabrics were padded (100% weight pick-up)
with following flame retardant formulations (Formulation 1 to Whiteness index as per Hunter Lab-Scale formula was
Formulation 6) as given below followed by drying at 100°C for evaluated using a computer aided Macbeth 2020
10 min and curing at 150°C for 5 min. Spectrophotometer. The evaluation of flammability
performances was also done in this work.
Formulation-1
45° inclined Flammability test -Jute fabric samples of
DAP-4%, 8%, 12%, 16%
specified length (15 cm length and 5 cm wide) were exposed
Borax + Boric add (7:3)-12% to a standard flame for a specified time (for cotton it is 1 s, for
jute It is 10 s, standardized In this laboratory) and was
DMDHEU-4% (active)
allowed to bum in an inclined plane (45° inclined) standard
MgClj catalyst-1 % flammability tester (Make: paramount India,) was used as
Formulation-2 per ASTM-D-1230-94 standard method12.

TSPP-4%,8%,12%,16% Limiting Oxygen Index (LOI) test was also done where LOI
values were determined in an standard LOI tester (Maker S
(Tetra-sodium pyrophosphate) DAP-4%
C Dey & Co, Kolkata) as per ASTM-D-2863-77 method13.
DMDHEU-4%(active)
TGA and DSC thermograms of jute samples obtained from
MgClj catalyst-1% Shimadzu Thermo Gravimetric Analyser (TGA-50),
Formulation-3 Differential Scanning Calorimeter (DSC-50) under air (for
TGA) and under nitrogen (for DSC) at heating rate of 10°C/
Borax+BoricAdd(7:3)4%,8%,12%,16% min, sample weight of 2 mg over a temperature range from
TSPP-12% 30°C to 500°C were performed by usual procedure10'11. Clo
& Tog value of treated fabrics were determined by using
DAP-4%
Sasmira Thermal Conductivity Apparatus conforming to the
DMDHEU-4%(active) standard method followed in Niven's guarded hot plate
instrument14.
MgCI2 catalyst-1 %

Formulatlon-4 RESULTS AND DISCUSSION

Sodium Perborate-4%, 8%, 12%, 16% Effect of Treatment with Fire Retardant Formulation-1
with Varying Dlammonium Phosphate (DAP)
DAP-4%
The changes in flammability and related textile properties of
DMDHEU-4%(active)
jute fabrics after being treated with Formulation-1 [Di­
MgCI2 catalyst- 1 % ammonium Phosphate (DAP) in varying amount, namely,
4%, 8%, 12%, 16% with Borax plus Boric Acid (7:3)-12%,
Formulatlon-5
DMDHEU Resin-4%, MgCI2 Catalyst-1 %] have been
Bo'rax+Boric acid (7:3)-4%,8%,12%,16% assessed and shown in Table 1

Vol 91, February 2011 19

Table 1 Physical and Fire Retardant properties of Jute fabric treated with Formulatlon-1 (varying DAP) and Formulation-2 ( varying
TSPP)

[Formulation-1. DAP-4, 8,12 and 16%, Borax-Bone Acid (7:3)-12%, DMDHEU-4%, MgClj-1%]

[Formulation-2 TSPP-4, 8,12 and 16%. DAP-4%, DMDHEU-4%, Catalyst (Mgcy-1%]

Physical properties 45° inclined flammability test

Treatments** Total solid Loss In Elongation, Bending Whiteness Flame After glow Char LOl, %
add-on, tenacity, % length, Index spread time, s length,
% % cm (Hunter) time, s cm

Untreated jute Ni - 3 10 4 0 62 03 49.0 55.0 BEL* 20 5

(BEL*) (12 5 cm)

Formulation 1a 21 0 23 4 12 41 59 61 55 0 50.0 80 28 0

Formulation 1b 25 0 23 4.31 42 58 38 60.0 48.0 70 30.0

Formulation 1c 29 0 27 453 45 57 46 65.0, S.E 450 60 31 0

Formulation 1d 33 0 40 4.73 4.8 55 73 15, SE 20 0 4.0 32.0

Washed — — —
----
■ 560 54 100 26.0
fabricld (1(f)

Formulation 2a 13 18.6 4.31 4.1 68.03 60.0 52.0 10.0 260

Formulation 2b 17 27 4.81 4.2 64.21 85, SE. 45.0 6.0 28.5
Formulation 2c 21 33 4.50 43 63.12 25.0, S.E. 35.0 4.0 30.5

Formulation 2d 25 38.5 4.90 4.1 63.15 16.0, S E. 25.0 4.0 31.0

Washed ______ ______ —— ______ _ — 65.0 50 0 BB.* 25.0

fabnc2d (2d1)

*BEL- Burned entire length S E.; Self Extinguishing

'•Di Ammonium Phosphate (DAP)% used In Formulation -1:1a: 4.0%, 1b' 8.0%, 1c: 12.0%, 1d' 16.0%.

“Tetra Sodium Pyro Phosphate (TSPP)% used In Formulatkm-2. 2a : 4.0%, 2b: 8.0%, 2c: 12.0%, 2d. 16.0%.

Test results in Table 1 showed that with the increase of DAP was initially Increased around 60-65 s from 55 s, after glow
concentration from 4% to 16% in the fire retardant time is decreased to 20 s from 50 s and char length was
Formulation-1, the fire retardant performance was found to also decreased to 6 cm. With nse in concentration of DAP
be improved steadily as reflected by flame spread time in upto maximum of 16% in the Formulation-1, keeping
450 inclined flammability tester and LOl value. DAP as well concentrations of other ingredients fixed and constant LOl
as mixture of Borax and Boric Add in combination were value was increased up to 32, char length was decreased up
reported to be reasonably good fire retardant agents for to 4 cm and flammability was much reduced generating
cellulosic material15. DMDHEU resin (N-methylol cross- somewhat near to self extinguished character showing
linking agents for cellulosics) was incorporated in this flame flame spread time up to 15 s which is minimum length of
retardant formulation with the expectation of utilising the burning (as shown by data of char length). However, this
binder type action of self-polymerised poly-DMDHEU film ( recipe (Formulation-1) was found to be not reasonably wash
in addition to cross-linking action of DMDHEU with fast
cellulosics) on the fibre surface, thereby to make such fire
retardant finishing relatively more durable16. LOl value of After washing this fire retardant fabric treated with
control bleached jute fabnc (base fabric) was found to be formulations 1d (DAP-16%) with 0.1% non ionic detergent
approx 20.5 and flame spread time to be 49 s, which bums solution for 30 min at room temperature (Washed fabrlc-ld'),
for the entire test length (12.5 cm) in 49-50 s, where after the fire retardancy performance was found to be much
glow persist for about 55 s. Relevant data from Table 1 diminished after washing where LOl value is reduced to 26,
indicate that with the application of 4%-16% DAP with fixed flame spread time was reduced to nearly 56 s .after glow
amount of other flame retardant chemicals ( Borax-Boric time become 54 s showing a resultant char length of nearly
add) along with DMDHEU-resin as binder and cross-linking 10 cm. Thus, it may be said that the fixation of fire retardant
agent with catalyst (Formulation-1), LOl value was found to chemicals used in Formulation-1 on jute fabric is not up to
be increased from 20.5 to around 32. Similarly, fire the desired level. Hence, this type of fire retardant
retardancy performances in terms of other criteria were also formulation is not durable / permanent type, but it
found to be improved with increase in concentration of DAP (Formulation-1) may be used to impart a good temporary fire
as evidenced by the test results, namely, flame spread retardancy finishing formulation particularly suitable for used
time, after glow time and char length. Flame spread time as cover/pandal fabric.

20 IE(I) Joumal-TX
These fire retardant finished jute fabrics also suffers some hydrolysable in any alkaline soap wash and that is why the
loss in tenacity in case of treatment with Formulation-1 said treatment Is not wash fast
With the increase of concentration of DAP in Formulation-1
With the increase in TSPP concentration in Formulation-2,
the percentage of loss in tenacity values were found to be
percentage of loss in tenacity values were found to be
gradually increased nearly 23%-40%. This may be due to
gradually increased nearly 18%-39% due to acidic
acidic nature of the chemicals used In the formulation, which
degradation of celluloses caused by acidic chemicals.
might have caused some degree of acidic degradation of
Whiteness index was increased with the increase in TSPP
major jute constituents particularly during curing However,
percentage due to the brightening effect of pyrophosphate
the bending length of these fire retardant treated jute fabrics
on jute. The bending length are also found to be increased
were found to be increased and whiteness Indices were
with the increase in TSPP percentage in Formulation- 2.
found to be decreased with the increase in concentration of
DAP in Formulation-1 Effect of Treatment with Fire Retardant Formulation-3
with Varying Concentration of Mixture of Borax and
Effect of Treatment with Fire Retardant Formulation-2
Boric Acid with Fixed Concentration of Tetra Sodium
with Varying Tetra Sodium Pyrophosphate
Pyro-phosphate
Flammability and related textile properties of jute fabrics after
The changes in important textile related properties of jute
being treated with Formulation-2 (Tetra sodium-
fabrics after being treated with Formulation-3 [mixture of
pyrophosphate in varying amount, namely, 4%, 8%, 12%,
Borax and Boric acid (in the ratio 7:3) in varying amount,
16% with DAP-4%, DMDHEU-4%, MgCI2 Catalyst -1%) have
namely, 4%, 8%, 12%, 16% along with the fixed
been assessed and shown In Table 1. Concentration of Tetra
concentration of Tetra Sodium Pyrophosphate-12%,
sodium-pyrophosphate (TSPP) in the formulation was varied
DMDHEU-4%, DAP-4%, MgCL, Catalyst-1 % ] have been
keeping other Ingredients/ additive chemicals constant It has
assessed and shown in Table 2. It was observed from the
been observed from the data shown in Table 1, that as the
data in Table 2 that there is an increasing trend of LOI
concentration of TSPP is raised from 4% to 16% In the fire
values, as the percentage application of mixture of Borax
retardant Formulation-2, the fire retardant performance is
and Boric acid (7:3) is increased, by considering other
found to be Improved reasonably as is reflected by flame
ingredients of the Formulation-3 where the flame spread
spread time tested by inclined flammability tester and LOI
time, after glow time and char length show a decreasing
values. The highest value for flame spread time and LOI values
trend. Maximum LOI was obtained for 12% application of
were achieved for 16% concentration of TSPP keeping the
borax and boric acid along with other ingredients. However,
concentrations of other ingredient in this formulation fixed. It
after washing the fabric treated with Formulation-3d (Fabric
was also observed that for application of 4% TSPP
3d'), fire retardancy again diminished and LOI value was
(Formulation-2a) fire retardant performances were not up to
reduced to 27 from 32 and char length was increased to
the desired level (LOI-26) but for 12% TSPP concentration
10 cm from 4 cm, and flame spread time becomes 75 s and
(Formulation 2c), LOI value was found to be 30.5 from 20.5
after glow time become 50 s. Normally, the mixture of borax
and flame spreading time becomes 85 s from 55 s and char
and boric acid decrease the rate of flame propagation to a
length were also found to be 4 cm only.
much greater extent than that is done by the individual fire
However, for 16% application TSPP (Formulation 2d) with retardant compound of equal weight Boric add melts on the
other common ingredients, LOI value achieved was 31, and application of flame and covers the surface of the cloth with a
char length becomes 4 cm after glow time becomes 25 s glassy layer, restricting the further flaming/burning of the
and the flame spread time was 16 s and after that flame fabric concerned.
appears to be self extinguished (SE) and shown in Table 1.
Jute fabric when treated with 8%-16% Borax-Boric Acid
However, after washing, the fabric treated with Formulation mixture (7:3) of Formulation-3, about 34%-40% loss of
2d (TSPP-16%), with 0.1% non ionic detergent for 30 min at tenacity occurs and maximum loss of tenadty occurred at
room temperature (washed fabric-2d') flame retardancy 16% application of mixture of Borax and Boric acid (7:3) A
performance was found to be deteriorated, showing LOI better balanced effect was obtained however with 12%
value to 25, and flame spread time 65 s .after glow time application of borax and boric acid mixture. The bending
50 s indicating that this treatment Is also not wash fast. The length were Increased with the increasing percentage
mechanism of action of phosphorous based flame retardant application of mixture of Borax and Boric add (7 3) content
compound like TSPP therefore appears to be also non but whiteness indices were not significantly affected with
reactive type, however even without any reaction, TSPP increase in concentration of mixture of Borax and Boric acid
decreases the amount of combustible volatiles and causes (7:3) in Formulation-3 for jute fabncs.
a proportional increase in the amount of char formation in
Effect of treatment with fire retardant formulation 4
cellulosics rendering fire retardant nature to the treated
with varying concentration of Sodium Perborate
fabric, where DMDHEU resin possibly helps to enhance
cellulose-phosphate anchonng by resinification15 However, The changes in important textile related properties of jute
this cellulose phosphate resin complex is easily fabrics after being treated with Formulation-4 (Sodium

Vol 91, February 2011 21

Table 2 Physical and fire retardant properties of jute fabric treated with formulation 3 (with varying Borax and Boric acid mixture)
and formulation 4 (with varying sodium perborate without borax and boric acid)

[Formulation 3: Borax-Bone Acid (7:3H-,B,12 and 16% TSPP-12% DAP-4%,DMDHEU-4%, MgCI2-1%)

[Formulation 4: Sodium Perborate-4,8.12 and 16 %. DAP-4%. DMDHEU-4% MgClj-1%1

Physical properties 45° Inclined flammability test

Treatments** Total solid Loss in Elongation, Bending Whiteness Flame After glow Char LOI, %
add-on, tenacity, % length, index spread time, s length,
% % cm (Hunter) time, s cm

2d
Untreated Jute Nil - 3.10 4 0 62 03 550 BEL* 20.5

CD
(12 5 cm)

Formulailcm 3a 25 34 433 4.7 60 95 68.0 35 7 29.0

Formulation 3b 29 36 5.03 5 63 75 105.0, SE. 22.0. 5 31 0

Formulation 3c 33 36 4.98 5.3 59.71 15.0, S.E j2.0 40 32.0

Formuiaflon 3d 37 39 3 383 5.4 62.95 15.0, S.E. 10 4.0 32.0

Washed 75.0 50 10 0 27.0

fabric 3d (3cT)
po
Formulation 4a 13 30 4.01 4 66.94 55.0 8.5 27.0

Formulation 4b 17 31 4.73 4.6 68.3 62.0, S.E. 47.0 6..5 29.0

Formulation 4c 21 33 4.39 5.3 68.67 105.0, SE. 180 4.5 30.0

Formulation 4d 25 385 5.21 5.7 70.35 25.0, S.E 8.0 4.0 31.0

Washed 58.0 3.0 11 25.0

fabric 4d (4cT)

*BEL: Burned entire length . S.E Self Extinguishing.

** Borax-Boric Add (7:3) used in Formulation -3: 3a • 4 0%, 3b: 8.0%, 3c: 12.0%, 3d- 16.0%
** Sodium Perborate used in Formulation -4:4a : 4.0%, 4b: 8.0%, 4c-12.0%, 4d: 16.0%.

Perborate in varying amount, namely, 4%, 8%, 12%, 16%, Borax and Boric acid(7:3) in varying amount, namely, 4%,
DMDHEU-4%, DAP-4%, MgCL, Catalyst-1 %) have been 8%, 12%, 16%, with fixed concentration of Sodium
assessed and shown in Table 2. LOI values of corresponding Perborate -12%, DMDHEU-4%;, DAP-4%, MgCI2 Catalyst-
treated jute fabrics show an increase In its values with the 1 %] have been assessed and shown in Table 3. The data in
increasing concentration of Sodium Perborate percentage in Table 5 indicate that there was a moderate but noticeable
Formulation-4 keeping the concentration of other ingredients improvement in fire retardant performance by almost all the
constant The flame spread time, after glow time, char treatments with Formulation-5 as Indicated by LOI values ,
length was also seen to be some extent decreased. The flame spread time, after glow tl(r?e and char length.. The fire
highest improvement in fire retardancy performance was retardant performance was indeeased with the Increase in
found with Formulation 4d [which has the highest concentration of mixture of Borax and Boric add (7:3) in
concentration of sodium perborate (16%)]. Durability of the Formulation-5, keeping concentration of other ingredients
fire retardant treatment was however moderate to poor. After fixed. Highest range of LOI 32-33 was achieved with
washing the fabric treated with Formulation 4d (fabric 4d'), Fonjiulatlon-5c or 5d and the flame spread time, after glow
the LOI value was decreased from 31 to 25. time and char length were found to be decreased
The tenacity values have also been shown a decreasing considerably. However, after washing the fabric treated with
trend with increase in Sodium per borate content, however Formulation-5d (fabric 5d‘) lose 20% of LOI value.
the loss of tenacity is within 3Q%-39%. The bending length The fire retardant performance dbserved might be attributed
values showed the increasing trend with increase in the to the combined effects of individual fire retardant nature of
application percentage of the Sodium Perborate. Whiteness Individual chemicals such as borax, boric add, and DAP.
indices were improved with increasing concentration of Borax, boric acid, act by depositing a coating of melted
Sodium per borate due to bleaching action of Sodium borax (boric acid reduces and facilitate melting of borax) on
Perborate. the surface of the fabric. Each fife retardant compound acts
Effect of Treatment with Fire Retardant Formulation-5 by different mechanism, eg, DAP alters the thermal
with Varying Concentration of Borax + Boric Acid degradation pattern of the fibre producing more non volatile
(7:3) with Fixed Concentration of Sodium Perborate component with higher char formation while Sodium
The changes in important textile related properties of jute Perborate might act as a booster for barrier action of borax
fabrics after being treated with Formulation-5 [mixture of and boric acid.

22 IE(I) Joumal-TX
Table 3 Physical and fire retardant properties of jute fabric treated with Formulation-5 (with varying Borax and Boric acid mixture
with fixed concentration of sodium perforate) and Formulation-6 (with varying pecofiame DPN)

[Formulation 5. Borax-Boric Acid (7.3>-4.,8,12 and 16%, sodium perborate-12%, DAP-12%, DAP-4%, DMDHEU-4%, Mg CL,-1%]

[Formulation-6: Pecofiame DPN-4, 8,12 and 16% DAP-4%, DMDHEU-4%, Catalyst (Mg Cl2>-1%]

Physical properties 46° inclined flammability test

Treatments** Total solid Loss In Elongation, Bending Whiteness Flame After glow Char LOI, %
add-on, tenacity, % length, Index, spread time, s length,
% % cm (Hunter) time, s cm

Untreated jute Nd - 3.10 4.0 62 03 49.0 55.0 BB_* 20.5

(BEL*) (12.5 cm)

Formulation 5a 25 314 5.17 44 665 600 50 0 80 27 0

Formulation 5b 29 33.5 4.61 47 68 48 65.0 480 6.5 30,0

Formulation 5c 33 38.5 6.14 4.2 63 37 12.0, S.E. 10 0 2.0 325

Formulation 5d 37 39.7 43 4.4 66 06 4, S.E. 8.0 20 33.0

Washed 50.0 500 10 0 270

fabric 5d (5cT)

Formulation 6a 13 31 3.98 39 59.64 76.0 55.0 10 0 28.0

Formulation 6b 17 30 4.11 39 60.16 70.0, SE. 45.0 6.5 30.0

Formulation 8c 21 35.7 5.16 43 58 92 60.0, S.E. 38.0 5.0 31.0

Formulation 6d 25 38 4.62 4.2 55.28 15.0, S.E. 12.0 40 32.0

Washed. 78.0 35.0 90 27.0

fabric 6d (6cf)

*BEL: Burned entire length : S.E.: Self extinguishing.

** Borax-Bone acid (7:3) used In Formulation -5: 5a : 4.0%, 5b 8.0%, 5a 12.0%, 5d' 16.0%.
** Pecofiame DPN used In Formulation -6:4a : 4.0%, 4b. 8 0%, 4c 12 0%, 4d: 16.0%.

But there is some degree of loss in tensile strength for use From the data in Table 3, it was observed that LOI values
of all the treatments with Formulation-5 and percentage of were increased with the increase in concentration of
toss in tenacity nearly 31 %-40%. Considering the observed Pecoflame-DPN in Formulation 6, keeping the concentration
data from Table 3, it may be said that treatment of jute with of other ingredients constant and LOI value become highest
12%borax plus boric acid (7:3) admixed with 4% DMDHEU (32) in this case for the application of 16% of Pecoflame-
and 1% MgCI2 gives the overall balanced fire retardant DPN along with other ingredients fixed. Flame spread time,
performance and textile related properties (/'e, treatment 5c) after glow time and char length for jute fabric was also found
to be decreased with the increase in the application of
Fabric handle also becomes stiffer to some extent for the
Pecoflame-DPN in Formulation-6. Bu,t, even in this case
treatment having Formulation-5, as indicated by bending
after washing, the treated fabric 6d (fabric-6d') lose some of
length data where as whiteness indices slightly Improved
its fire retardant property and LOI value decreased from 32 to
with the increase of mixture of Borax and Boric acld(7:3) in
27 (Treatment 6d'). Thus, THPC, which was earlier reported
Formulation-5.
to provide excellent fire retardant performance for cotton, is
Effect of Treatment with Formulation-6 with Varying not to be that successful on jute. It is thought that the
Concentration of Pecofiame - DPN. degree of phosphorylation is lesser in case of jute than
cotton in the said curing condition.
The changes in important textile related properties of jute
For these treatments, the tenacity values were found to
fabrics after being treated with Formulation-6 with
follow a decreasing trend and loss of tenacity was found to
commercial grade of fire retardant agent (Pecoflame-DPN in
be within 31%-38%. For increasing concentration of
varying amount, namely, 4%, 8%, 12%, 16%, fixed
Pecoflame-DPN (4%-16%o.w.f.) In Formulation-6, keeping
concentration of DMDHEU-4%, DAP-4%, MgCI2 Catalyst-
other ingredient constant Fabric handle did not much
1%) have been assessed and are shown in Table 3.
altered as evident from the bending length values with the
Pekoflame-DPN, a commercial grade fire retardant agent,
increasing percentage application of the Pecoflame-DPN in
based on reactive organophosphorous compound (Tetra-kis
Formulation-6, keeping other ingredients constant
Hydroxy-methyl Phosphonium Chloride) type. THPC has
been reported earlier to provide excellent fire retardant Whiteness indices were decreased with increase in
performance on cellulosics18. concentration of Pecoflame-DPN in Formulation-6.

Vol 91, February 2011 23

 --------- ►
Endotherm (AH) exotherm
FLow of heat

Temperature, C
30 100 200 300 400 500
Temperature, °C Figure 2 Thermograms of Thermogravimetrlc Analysis of

Figure 1 Differential Scanning Calorimetric Thermograms of a) Scoured and Bleached JutefControl)

a) Scoured and Bleached Jute(Control) b) Borax-Boric Acid treated Jute fabric

b) Borax-Boric Acid treated Jute fabric c) Jute treated with DAP(12%) based formulation 1

c) Jute treated with DAP(12%) based formulation 1 d) Jute treated with Sodium Perborate(12%) based
formulation 5
d) Jute treated with Sodium Perborate(12%) based
formulation 6 e) Jute treated with Tetra Sodium Pyro Phosphate (12%)
based formulation 3
e) Jute treated with Tetra Sodium Pyro Phosphate (12%)
based formulation 3
shows, however, relatively a lower degree of weight loss at
all the temperature zone, probably due to the small
Analysis of DSC and TGA Thermograms resistance and delayed thermal action on jute component
due to the film formed of borax and boric acid on jute fibre
Thermograms 1(a) to 1(e) for Differential Scanning surface. The minor trough at 180°C may be attributed to the
Calorimetric (DSC) study, and thermogram 2(a) to 2(e) for heat absorbed by borax during its melting .
Thermo-Gravimetric Analysis (TGA) of jute and chemically
treated Jute samples are shown in Figure 1 and Figure 2, DSC thermogram 1(c) [fe, for DAP and borax-boric add
respectively. DSC thermogram 1(a) for control jute shows Formulation-1] show an exothermic peak at 93°C instead of
broad endothermic peak at 80°C (for evaporation of moisture endothermic peak at 80°C in rawjute or only 12% borax plus
present in jute), a broad exotherm with a humpat293°C (for boric acid(7:3) treated jute, the exact reason for which was
degradation of hemicellulose part of jute), a sharp not well understood from this multi component/mixed
endotherm, ie, peak at 364°C (for degradation of cellulose treatment However, It may be presumed to be due to
component ofjute) and a broad exotherm with small hump at excess of unreactive dlammonium phosphate evolving heat
425°C (for degradation of lignin part of jute), Figure 1, which during its dissociation (which however is absent In other
corroborates earlier findings of thermal behaviour study of DSC thermograms 1(d) and 1(e) though there Is also
control jute by DSC and TGA6’7'8’11. TGAThermogram 2(a) presence of DAP in those formulations but In much low
for control jute shows weight loss of 8% at 80°C, 10% at extent (4%). From DSC thermogram 1(c), two distinct
180°C, 27.6 % at 270°C, 64.6% at 370°C, 78.1 % at 435°C features of Its thermal behaviour is evident, (i) a bit early
and 94.1 at 500°C, respectively, (Table-4). The results of thermal degradation of part of hemicellulose (at 270°C),
TGA and DSC thermogram of the same sample therefore are cellulose (at 354°C) at lignin (at 410°C) and (II) a bit delayed
in much tune with each other. thermal degradation of rest part of hemicellulose (at 319°C),
cellulose (at 390°C) and lignin (at 490°C) as compared to the
However, jute fabric separately treated with 12% mixture of same for control jute [thermogram 1(a)], The early
borax and boric acid (7:3) shows almost a similar pattern of degradation of part of major three jute constituent might be
DSC thermogram (1b) as compared to that obtained for due to complexlng of Jute cellulose/hemicellulose/IIgnin and
control jute [thermogram 1(a)] except a small and minor phosphate compound providing more charformation11, while
endothermic trough at 180°C. The TGA thermogram 2(b) the delayed thermal degradation of the other part of the
24 IE(I) Joumal-TX
Table 4 Weight loss of Jute samples for heating under different temperature zone during thermo-gravimetric analysis

Treatment Weight Weight Weight Weight Weight Weight

loss% |08S% loss% loss% |08S% loss%
at eo°c at180°C at 270°C at 370°C at 435°C at 600°C

a) Nil (control bleached jute) 8 10 27.6 64.6 781 94 1(5 9)*

b) Jute treated with borax-boric acid (7 3) only 70 92 26 8 58 1 71 6 89 2(10 8)’
c) Jute treated with DAP-12% based
fonmulation-1 with 12% borax-boric 65 84 20.1 56 5 68 2 82 5(17 5)'
acid (7:3), DMDHEU-4% and MgCtj-1%

d) Jute treated with 12% sodium perborate

based formulation-5 with 12% borax-boric 6.0 7.2 18.4 52.6 642 76.2(23 8)’
acid (7:3), 4% DAP, DMDHEU-4% and MgClj-1%

e) Jute treated with 12% tetra sodium

pyrophosphate based formulation 3 with 8.2 121 23-2 545 00.1 81 8(18 2)’
12% borax-bone Acid (7 3), 4% DAP,
DMDHEU-4% and MgCL,-1 %

* Data in the parentheses Indicate the percentage weight of residue left at 500°C for untreated and treated jute fabrics

same three major constituents might be attributed due to a of 23.8%). Thus DSC and TGA thermograms of sodium
low degree of cross-linking reaction between Jute cellulose/ perborate treated jute (with Formulation-5) shows relatively
hemicellulose/lignin component and N-methyloI end groups higher thermal stability and lower extent of weight loss
of binder resin (DMDHEU) used8. during thermal degradation than other treatment studied
Corresponding TGA- thermogram 2(c) shows weight loss of here.
6.5% at 80°C, 8.4% at 180°C, 20.1% at 270°C, 56.5% at DSC thermogram-1 (e) (for Tetra sodium pyrophosphate and
370°C, 68.2% at 435°C and 82.5% at 500°C (leaving residue borax-boric add based fire retardant Formulation-3) shows
of 17.7%) of Table 4 indicating higher thermal stability upto the moisture evaporation peak at 82°C, two step thermal
270°C and after which the rate of weight loss was increased degradation of hemicellulose at 270°C and 319°C [much
showing a sharp fall, but resulting an overall lower weight similar to that occur in thermogram 1(c) and 1 (d)j, but the
loss than that occur for control jute at comparable heating thermal decomposition of cellulose and lignin component of
zones. this tetrasodium pyrophosphate (TSPP) treated jute were
DSC thermogram 1(d) [for Sodium Perborate and Borax- found to occur at single temperature zone that too only at
boric acid based Formulation-5] shows endothermic peak higher temperature zones showing endothermic peak( at
for moisture evaporation at 82°C, a minor trough at 180°C 390°C for degradation of cellulose and exothermic peak at
(for melting of borax), and also two step thermal degradation 490°C for degradation of lignin) than the same occur in
of jute hemlcellulose (at 270°C and at 319°C) and two step control jute [thermogram 1(a)] for the same jute
thermal degradation of cellulose (at 354°C and 390°C and components. It therefore indicates that probably there are no
also two step thermal degradation of lignin at 413°C and formation of any complex compound between tetrasodium
490°C very much similar to those found in thermogram 1 (c)], pyro-phosphate with either of cellulose and lignin
except an additional exothermic peak at 93°C In component of jute, but the delayed decomposition of these
thermograml(c) which was absent in thermograms 1(a), two major components cellulose and lignin may be
1(b), 1(d) and 1(e). attributed to the effect of crosslinking of the same with
DMDHEU resin. When jute was treated with fire retardant
Thermograms 1(c) for 12% DAP based fire retardant Formulation-3, TGA thermogram 2(e) shows a relatively
Formulation-1 treated jute and 1(d) for 12% Sodium higher weight loss upto 270°C to 320°C temperature zone;
Perborate based Formulation-5 treated jute differ and thereafter the rate of weight loss is reduced as
quantitatively in their amount of heat absorbed and evolved in compared to that found in TGA thermogram 2(d) at the
thermal degradation of each of major three jute components comparable temperature zone. TGA thermogram 2(e) shows
showing relatively lower heat of enthalpy (DH), for Sodium weight loss of 8.2% at 80°C, 12.1% at 180°C, 23.2% at
Perborate formulation five treated jute [thermogram 1(d)] 270°C, 54.5% at 370°C, 60.1% at 435°C and finally 81.8%
than DAP treated jute with (Formulation-1) jute [thermogram at 500°C, (leaving a residue of 18.2%) Thus the superiority of
1 (e)], keeping other ingredients same. TGA thermogram 2(d) Sodium Perborate as flame retarding agent than other
also shows a relatively lower rate of weight loss at different compounds used were further evidenced by this study of
temperature zones of heating as compared to the same for thermal behaviour of raw and chemically treated jute fabric.
TGA thermogram 2(a), 2(b) and 2(e). It shows the weight
loss of 6% at 80°C, 7.2% at 180°C, 18.4% at 270°C, 52 6% Study of Thermal Resistivity
at 370°C, 64.2% at435°C, 76.2% at 500°C (leaving residue In the present study, it appear, from the data in Table 5

Vo/ 91, February 2011 25

 Tabla 5 Thermal resistivity properties of Jute fabric treated with fire retardant Formulations t to 6
Treatment Time required for temperature Clo value Tog value
to change from 60°C to 49°C), mm (Clo x 0.645)
Nil (control bleached jute fabric) 3 1 31 0 84
DAP(12%)based Formulabon-1 5 1 45 0.94
TSPP(12%)based Formulation-2 5 1 45 0.94
Borax-Boricactd (7:3)-12%based Formulatkm-3 7 1.7 1.09
Sodium Perborate(12%) based FormulatK>n-4 5 1.45 0.94
Sodium Perborate-12% and Borax-Bone add

(7.3) based Formulahon-5 10 23 1 48

PecoftameDPN-12%bssed Formulation-6 7 1.70 1.09

that, by treatment of jute fabric with Formulation-1 to REFERENCES

Formulation-6, both the Clo values and Tog values were
1. A R Horrocks. 'Flame-retardant Finishing of Textiles'. Rev. Prog.
found to increase indicating improvement in thermal Coloration., vol 16,1986, p 62.
resistivity (flow of heat from one furnace to the other surface
2. A K Samanta. 'Chemical Finishing of Jute and Jute Blended Textiles:
of the fabric/air). The highest Clo/Tog value was observed for A Review1. Colourage, February 1995, p 37.
the fabric treated with Formulation-5, indicating its highest
3. S N Pandey, A Day, S N Chattopadhyay and N C Pan. 'Recent
thermal resistivity than the same fabric treated with any Advances In Resin Finishing of Jute and Jute Blended Textiles'. Ind
otherfbrmulation studied. Text Jour., July 1993, p 30.
ASK Banaijee, A Day and P K Ray. 'Fireproofing Jute'. Text. Res J, vol
CONCLUSIONS
56, 1986, p 338.

Jute fabric can be made reasonably fire resistant by a variety 5. U S Shanma. 'Flre-retardancy of Jute Fabncs with Potassium Sodium
Tartrate (Rochelle Salt), Colourage, vol 33, April 1986, p 17.
of chemical finishing treatments using a judicial combination
of different types of fire retardant compounds. Among the fire 6. S K Bhadurl, M D Mathew, A Day and S N Pandey. Thermal Behaviour
of Jute Fiber and Its Components.I.D.S.C.Studies'. Cellu. Chem. &
retardant formulations studied in the present work,
Tech., vol 28,1994, p 391.
Formulation-5c [Borax-Boric Add (7:3) -12%, Sodium
7. S N Pandey, A Day and M D Mathew. "Thermal Analysis of Chemically
Perborate-12%, DAP-4%, DMDHEU-4% and MgCI2-1%]
Treated Jute Fabric*. Text Res. J, vol 63, no 3, 1993, p 143.
gave the balanced fire retardant performance at the cost of
8. P Ghosh, A K Samanta and D Dev. 'Simultaneous Free Radical
some loss of tenacity of jute fabric, showing LOl value 32 to
Polymerisation and Addle Polycondensation of Acrylamide-
33. However, it might be noted that the durability of the fire Formaldehyde Resin on Jute Fabric’. J. Appl Polymer Sc., vol 64,
• retardant performance of all the six formulations after normal 1997, p 2473.
soap (2 g/T) washing were found to be poor to moderate for 9. AK Samanta, G Basu and P Ghosh. 'Effect of Glycol and Acrylamide
jute fabric except Formulation-5 using Sodium Perborate Treatments on Textile Related Properties of Jute Fibres'. Journal of
along with borax-boric acid and other common additives Natural Fibres, vol 4, no 4, 2007, p 59.
which could withstand at least few cycle of washing and 10. A K Samanta, G Basu and P Ghosh. 'Structural Features of Glycol
was semi-durable in nature. However, study of thermal and Acrylamide Treated Jute Fibres’. Journal of Natural Fibres, vol 5,
4. 2008, p 444.
degradation pattern and thermal resistivity also indicate the
superiority of Formulation-5 particularly 5(c) or 6(d) over all 11. R K Basak, S G Saha, A K Sarkar, MSaha, N N Das and A K
Mukherjee'. Thermal Properties of Jute Constituents and Flame
other formulations studied in the present work. Retardant Jute Fabrics'. Text Res J, vol 63, 1993, p 658.

ACKNOWLEDGEMENTS 12. ASTM D 1230-94. 'American Sodety for Testing and Materials'.
Annual Book of ASTM Standards, Philadelphia, Pennsylvania, USA)
The authors express their sincere thanks to Prof (Dr) Prabir 1994, p 319.

Ray, Principal, Institute of Jute Technology, Kolkata for all 13. ASTM D 2863-77. 'American Sodety for Testing and Materials'.
sorts of administrative support to carry out this work. The Annual Book of ASTM Standards, Philadelphia, Pennsylvania, USA,
September, 1977, p 635.
authors are also thankful to AICTE ,New Delhi for the grant-
14. IS:2702-1965. Determination of Thermal Resistance of Textile
in-aid received for the RPS project (F No. 8022/RID/NPROJ/
Fabrics, in BIS(ISl).
RPS-33/2003-04) during 2004-07 and also to JMDC,
15 W A Reeves and Jr G L Drake. 'Flame Resistant Cotton'. Morrow
Ministry of Textiles, Govt of India for sponsoring another
Publishing Co. Ud., England. 1971, p 27.
new research project under Jute Technology Mission -MM-
16. P Baja] and S Chakrapanl. 'Flame Retardant, Durable Press Finishes
IV-scheme 7.1 as project no. 10 on 'Development of fire
tor Cotton and Polyester/Cotton Blends’. Text Res J, vol 54, 1984,
retardant jute fabric1 during 2008-2011. p 619

26 IE(I) Joumal-TX
 Fire Retardant Finishing of Jute Fabric and its Thermal
Behaviour using Phosphorous and Nitrogen based
Compound

A K SAMANTA*, A BAGCHI AND S K BISWAS

Institute of Jute Technology, 35 Ballygunge Circular Road, Kolkata-700 019

ABSTRACT

Bleached jute fabrics have been subjected to treatment with different fire retardant formulations
based on binary mixtures of Phosphorous - Nitrogen compound by pad-dry cure process.
Phosphorous containing compound e.g., Ortho Phosphoric Acid/DAP and Nitrogenous com­
pound e. g. Urea/Thio Urea/Dicyan-diamide as well as a commercial fire retardant finishing agent,
Pyrovatex CP (N-methylol di methylphosphonopropionamide) are also standardized ahdstudied
for jute fabric. The fire retardant performance of each formulation is investigated at different
concentration in terms of LOI value, flame spread time, afterglow time, char length. The effect of
fire retardant treatments on the various physical properties were also measured. Most of the fire
retardant formulations showed high fire retardant performance showing LOI value in the range of
27 to 38. Ortho Phosphoric Acid in combination with Urea imparts highest fire retardancy though
it is also associated with higher strength loss. However, all the above fire,retardant finished
fabric samples showed loss of nearly20- 30% of LOI value on soap washing! Loss of tenacity om
such fire retardant treatment was around 15-50% in different cases. Thermal studies, showed
that on fire retardant treatment formation of volatile products are reduced.

Keywords: Phosphorous Compounds, nitrogen compounds, fire-retardant finish, jute fabric,

limiting oxygen index, thermal behavior, thermo-gravimetric analysis, differential scanning
calorimetry.

INTRODUCTION inherent properties e.g. flammability, high

moisture absorption, and susceptibility to
Jute and jute based fabrics are gaining rotting which have restricted its growth of use
popularity in domestic and international field towards protective textiles. Now-a-days, fire-
due to eco friendliness and biodegradability retardant textiles are being produced in large
characteristics. Golden fibre Jute has certain quantities due to prevailing legislations for fire

J Polym. Mater. Vol 28, No. 2,2011,149-169

© MD Publications Pvt Ltd.
Correspondence author e-mail: ijtaksamanta@hotmail com
150 A K. Samanta et al

safety and public awareness. Demand for fire of flame retardant is greatly increased when
retardancy of jute material is also increasing using together with nitrogen compounds19-10-191
in area like upholstery, automotive fabrics, floor Esterification of cotton cellulose to cellulose
coverings, Tenting etc For the development of phosphate has found to produce a durable
fire retardant finishing of jute, proper choice of flame retardant by using Phosphoric acid or
chemicals along with process parameters are different phosphate compounds with or
important. without nitrogen compounds. Addition of urea
reduces the tendering effect of
Cellulosic fabrics can be made fire-resistant
phosphorylation apd also improves fire
by treatment with different non-durable and
retardancy111 Subsequent modifications have
durable fire retardant formulations, which are
used other amines such as dicyandiamide,
readily available in the review literature by
thiourea, melamine, acrylamide and showed
Horrocks111.
less tendering or improved fire retardancy1101.
There are many reports on fire retardancy of The major problems associated with fire
cotton, but similar study on jute is scanty. retardant of jute are higher chemical add-on,
Some, preliminary studies on temporary flame noticeable strength loss, yellowing of colour,
retardancy of jute has been also reported fabric stiffness etc. It is thought appropriate
earlier by Banerjee et al|2] using borax- boric to undertake an integrated study on fire
acid and diammonium phosphate Sharma[3> retardant finishing of jute fabric using different
suggested potassium-sodium tartarate combination of Phosphorous and Nitrogen
(Rochelle Salt) as a fire retardant for jute fabric. based fire retardant compound. It is also felt
A short review on fire retardancy finishing of essential to study the thermal decomposition
jute is also available in^review paper of behaviour of such chemically modified jute
SamantaI4f Most of the finishing so far reported substrate for understanding the relative
is not much durable to washing changes of thermal degradation behaviour
under different temperature ranges.
Basak et al.[5! studied the thermal properties
of fire retardant jute fabric impregnated with Accordingly, the present work has been
urea and di ammonium phosphate. Preliminary undertaken to make jute fire retardant using
study of thermal behaviour of jute fibre and its binary combinations of different phosphorous( P)
components has been reported16-71 earlier for and nitrogen (N) compounds like
an understanding its thermal degradation orthophosphoric acid urea, di Ammonium
behaviour and nature of byproducts under heat/ phosphate(DAP)-urea, DAP-thiourea, DAP-
flame. DSC and TGA studies have been dicyandiamide in different ratios.
reported1®1 for jute fibres treated with a Borax-
formaldehyde-sodium hydrosulphite (BFH)
EXPERIMENTAL
flame retardant formulation.
Jute Fabric
It is well-known that ‘Phosphorous-containing
Conventional H202bleached plain weave jute fabrics having
compounds are effective in diminishing 63 ends/dm(count 195 tex), 59 picks/dm(count 214 tex),
flammability of cellulose and the effectiveness 220 g/mJ (area density) were used for the present study.

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabnc and its Thermal Behaviour using Phosphorous and 151
Nitrogen based Compound

CHEMICALS Finish KVS(DMDHEU i e dimethylol dihydroxy ethylene

urea) resin from Clariant India Mumbai was also used
Laboratory grade Urea (Nice Chemicals Pvt Ltd , Kochi),
Ortho-Phosphoric acid (85%) of S D Fine Chern Ltd ,
Mumbai, Thiourea (Sisco Research Laboratories METHODS
pvt ltd ,Mumbai),DiAmmomum Phosphate(DAP) of Loba
Chemie Pvt Ltd , Mumbai, Dicyandiamide( Loba Chemie Flame Retardant Treatments with different
Pvt Ltd..Mumbai) and a commercial fire retarding agent Formulations Bleached jute fabrics were padded
PyrovatexCPfHuntsman, Mumbai,(old Ciba)], have been (100% weight pick-up) with following flame retardant
used as fire retardant formulations as given below followed by drying at 100°C
for 10 min and curing at 15Q°C for 5 mm

Formulation-1 Formulation-2 Formulation-3

Urea -10%, 20% Urea - 20% Thiourea- 8%, 10%
OrthoPhosphoric Acid- Di ammonium Phosphate- Di ammonium Phosphate-
4%, 6%, 8%, 10% 5%, 10%, 15%, 20% 5%, 10%, 15%

Formulation-4 Formulation-5
Dicyandiamide-8%, 10% PyrovatexCP -10%, 15%,
Di ammonium Phosphate- 20%, 25%, 30%
5%, 10%, 15%, DMDHEU-8%(solid addon)
OrthoPhosphoric Acid-2%,

Besides, fire retardant finishing treatments of jute mm/mm and a pretension of 0 5 N. The final gauge
fabric with the above formulations11'5’, separate length(sample size) of the fabric sample was 50 mm x
treatment were also carried out using each of the 20 mm under the jaws.
individual fire retardant chemicals used in the fire
retardant formulations e g Urea, Ortho-Phosphoric
Acid, Diammonium Phosphate, Thiourea and Measurement of Whiteness
Dicyandiamide at specified concentration respectively Indices
by the same procedure and conditions of pad, dry,
Whiteness index as per Hunter Lab-Scale formulat,1) of
cure technique for understanding the effect of
the selected jute fabric samples were directly evaluated
individual chemicals on achieving the fire retardant
using a computer aided Macbeth 2020 plus reflectance
performance
spectrophotometer (with D65 standard illummant and
10° standard observer setting) and associated colour
Determination of Fabric Stiffness (Bending measurement software
Length)

The bending length of the selected fabric samples Testing of Flammability Performances
were measured as per IS-6490-1971 method using 45° Inclined Flammability Test
Cantilever type Sasmira fabric stiffness tester
Selected untreated and treated jute fabric samples of
specified length(15cm length and 5 cm wide) were
Measurement of Tensile Properties exposed to a standard flame for a specified time (for
(Tenacity) cotton it is I sec, for jute it is 10 sec, standardized in
this laboratory) and was allowed to burn in an inclined
Breaking tenacity (cN/tex) of selected fabric samples plane (45° inclined) Standard flammability tester(Make'
were measured by the raveled strip method as per IS- Paramount, India,) following ASTM-D-1230-94 standard
1969-1985 method using an Instron (Model-1445) CRT- method1’21 The fabric samples was mounted at 45° angle
Universal tensile tester with a traverse speed of 100 in a specimen holder and was then exposed to a

Journal of Polymer Materials June 2011

152 A K Samanta et al.
\

standard flame of specified height exposed at 90° RESULTS AND DISCUSSION

with the specimen for 10 second and is left for burning,
to note flame spread time, afterglow time, and char
length (in cm) after the burning Effect of various P or N based Fire
retardant chemicals on jute fabric
Determination of Limiting Oxygen Index First of all, the fire retardant performance of each
Limiting Oxygen Index (LOI) are critical oxygen index N/P based chemicals on jute fabric is
values indicate the relative measure of flammability of investigated at different concentration in terms
any materials or textiles. LOI values of selected
of LOi value, flame spread time, afterglow time,
untreated and treated fabric samples were determined
in a standard LOI tester (Make SCDey&Co , Kolkata) char length (as per test result obtained from
as perASTM-D-2863-77 method by using the following standard 45° inclined flammability tester),
formula changes in tenacity were also evaluated and
shown in Table 1
Thermal Behaviour by TGA and DSC
Analysis LOI value of untreated jute fabric is found to be
20.5, flame spread time is 55 sec and after glow
TGA and DSC thermograms of untreated and treated
jute fibre samples (finely crushed) after being taken time is 49 sec. Urea is applied on jute fabric at
out from the corresponding untreated and treated different levels (5%, 10%, 15%, 20% and 25%
jute fabrics were obtained from a Shimadzu Thermo- owf). Urea alone does not show much flame
Gravimetric Analyser(Model-TGA-50) and Shimadzu
Differential Scanning Calorimeter (Model DSC-50)
retardant action at lower concentration(5% &
under atmospheric air (for TGA) and under flowing 10%). However, moderate fire retardancy is
nitrogen (for DSC at nitrogen flow rate of 50 cm3/mm) achieved at 15% to 25% concentration level
respectively at heating rate of IO°C/min, using a pre­
20% Urea (i.e, calculated Nitrogen
fixed sample weight of exactly 2 mg over a temperature
range from 30°C (ambient) to 500°C, following usual content- 9.3%) treated fabric showed LOI value
procedure15’671 25.5. Both Thiourea (2%-10% owf) treatment
and dicyandiamide(2%-10% owf) treatment
Scanning Electron Microscopy (SEM)
showed marginal improvement in fire retardancy
The surface morphology of untreated (bleached) and and rendered mild fire retardancy on jute fabric
fire retardant treated jute fibre samples taken out from
only at 8% and 10% concentration level showing
the corresponding jute yarns of the untreated
(bleached) and correspondingly treated jute fabrics Lor value 23.5 and 24 respectively.
was examined using JEOL Scanning Electron
Microscope (Model: JSM-5200) The fibre samples for Ortho-Phosphoric acid treated jute fabric (4%,
the SEM study were prepared with Gold-Palladium 6%, 8% and 10% owf) achieved effective fire
alloy coating following a standard procedure iw,'B1 retardancy at all level of concentrations used
and LOI value observed to 30.5 is obtained at
Fourier Transform Infrared Spectroscopy
(FTIR) 8% H3P04(caiculated Phosphorous content-
2.5%) treatment. However, above 6%
Selected jute fibre (finely crushed) samples
(3mg)taken out from untreated and treated fabrics concentration level of H3P04, it causes
were examined in a double beam FTIR noticeable loss in tensile strength of treated
spectrophotometer (BOMEM.MB 104) using KBr disc fabric.
technique172021’221
Diammonium Phosphate (DAP) treated jute

Journal of Polymer Materials June 2011

 TABLE 1. Fire Retardant performance of jute fabric treated with different N/P fire retardant chemicals

No Treatment Calculated Calculated j Loss in Flammability property

CO
TD
■o
u»
•5
o
o'-
S:

Q.
>>
I Tenacity Limiting I| 45° Inclined Flammability Test |

z <0
0)
o
cr*
1

J
c

ro
CO

xO Q.
|

Q.
(applied Oxygen name j
chemicals) chemicals) Index Value spread glow time length
(%) 101
time (sec) (sec) (cm)

-
Jute, untreated 20.5 55 49 BEL

CM
09
Urea 5% 2.33 45 22 5 44 BEL

CO
Urea 0% 4.66 56 24 64 43 BEL

1
Urea 15%
CO
CO
6 99 62 25 68 BEL

LO
Urea 20%
O

9.32 75 25 5 40.S.E 36

CO
S6

T”
o
Urea 25%

CO
CD
CO
in
11.65 26 35

1--
O-phosphoric acid 2% 0 63 25 5 65,S E 38 10 4
!

CO
28
CM
O-phosphoric acid 4%
CO
1 26 28 30

CD
O-phosphoric acid 6% CM
LU LU

1
(f) c6
cm
89 35 30 23

o
O-phosphoric acid 8%
CM
UJ
CO
CO CO CO

2 52 46
o'

30 5 20
O-phosphoric acid 10%

CO
T—
CO

3 15 56 7,S E 28

1
I

CM
Thiourea 2% 3.6
r-

.73 22 43 BEL

CO
Thiourea 4% 1 CM
CO
CD
LU

46 47 76 40

**r
Thiourea 6% 2 19 5.6 23 5 80 | 40 BEL

to
Thiourea 8%
CO

2 92 62 23.5 38 BEL

i£>
Thiourea 10% 3.65 65 23.5 84 37 BEL
DAP 5% 1
111

1.06
CO

17 29
<4

28 34

CO
DAP 10% 2 12 2 34 34 30 0 10.S.E 25 38

<

05
Q
Q_
to
0s*
«s°
3 18 3.51 48 30 5 15,SE 22 29
20 DAP 20%
CO
z

4.48
CO

4.68 55 20

CM
CO
09
Dicyan diamide 2%
LU
CD

42 23 42

1
22 Dicyan diamide 4% 2.6 4.3 23.0 65 ! 39 BEL
23 Dicyan diamide 6% 1 69
CD
UJ
—1

39 1
4.8 23 5 37

CM
to
24 Dicyan diamide 8% 56 23 5 75 36 BEL
25 Dicyan diamide 10% |
99
o>
"in
LU
ro
Fire Retardant Finishing of Jute Fabnc and its Thermal Behaviour using Phosphorous and
Nitrogen based Compound

24 82 35

* BEL : Burned entire length, S E,; Self Extinguishing

Journal of Polymer Materials June 2011

153
154 A K Samanta et al

fabric (5%-20% owf) show a good degree of Effect of treatment with combination
flame retardancy. I0% DAP treated jute fabric of Urea and Ortho-Phosphoric Acid
(calculated Phosphorous content-2 3%) showed (Formulation -1) Reaction Mechanism
LOI value of 30. However, use of more than 10%
Phosphorylation reaction of jute: The cellulose
DAP causes marginal improvement in LOI value
and hemi-cellulose of jute reacts with phosphoric
with higher loss in fabric tenacity. It is observed acid(Di Ammonium Phosphate also on heating
that Phosphorous based flame retardant e g. converts to Phosphoric Acid) at elevated
Ortho-Phosphoric acid, DAP is more effective temperature to form phosphate ester H3P04 at
than Nitrogenous compound. high temperature reacts with the hydroxyl
Hence, five different combinations of fire groups of jute fibre. Based on reported
literature121’221, the following structure for
retardant formulation have been selected
phosphorylatedjute is given.
consisting of one nitrogen based compound and
one phosphorous based compound at different The changes in flammability and related textile
ratio and concentrations to get the desirable properties of jute fabrics after being treated with
fire retardant finish on jute fabric by combined combination of fixed % of Urea (10 % or 20 %
effect of N and P-compounds owf) and Ortho-phosphoric acid(H3P04) in

O O

Ceil-CH,OH + HO-P-OH-* Cell-CH,-0-P-0H

I I
OH OH

2NH2-CO-NH2-> NH2CONHCONH2 + NH3

o o
Cell-CH„- O - P - OH + 2NH„ -> Cel!-CH„-0-P-ONH
I
" OH ONH4

varying amount (viz. 4%, 6%, 8%, 10%) under It is already mentioned the superiority of
specific controlled conditions of treatment have phosphorous compounds for flame retardancy
been assessed and the results are shown in over nitrogen compound. Hence, H3P04is the
Table 2. main fire retardant agent but function of Urea
is manifold e.g. moderate flame retardancy,
Comparison of data with table 1,Table 2
have some buffer action, facilitates formation
indicates that jute fabric treated with Urea- H3P04
combination showed higher flame resistance of phosphate ester with cellulose, reduces
character than use of either H3P04 or urea acidity of the formulation, reduces loss in
individually at comparable dosages and treatment tenacity and swells cellulose to enhance
conditions. penetration11'131.

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 155
Nitrogen based Compound

Relevant data in Table 2 also indicate that with Again, for Urea- H3P04 formulation, with 20%
the application of 4-10% H3P04with 10% urea, urea and H3P04 (4-10%), somewhat better fire
LOI value is found to increase to 31-37(from retardance performance with lesser loss of
original LOI value 25) with simultaneous loss in tenacity is observed LOI value reached up to
tenacity occurred 10% urea and 8% H3P04 38.5 with lesser loss in fabric tenacity (34%)
showed optimum flame retardancy of jute Use of higher concentration of Urea (20% on
fabric with LOI value of 36 and char length of weight of the fabric and calculated nitrogen
3cm. It may also be noted that 10 % Urea and content 9.2 %) and 8 % H3P04 (calculated
8% H,PO. treatment shows less loss of fabric phosphorus content 2.5 %) gives the maximum
tenacity (36 %) whereas application of 10% Urea
LOI value of 38. However, if H3P04 concentration
and 10% H,PO,
3 4
treatment causes 57% loss of
tenacity of jute fabric.
TABLE 2. Physical and Fire Retardant properties of jute fabric treated with fire retardant Formulation-I with Urea and
Ortho Phosphoric Acid

Treatments N%&P% Physical properties Flammability properties

(Applied content Tensile Bending Surface 45° Inclined L.O l.%
on weight of applied Properties Properties Appea­ Flammability test
of fabric) chemicals rance
calculated Properties
% Loss Bending Whiteness Flame After Char Limiting
in Length Index Spread Glow Length Oxygen
Tenacity (cm) (Hunter) Time Time (cm) Index %
(sec) (sec)
Untreated Nil Nil 3.8 75 20 49.0 55 0 ‘BEL 20 5
(BEL*) (12 5)
U/ea-10%+ N-4 66, P-1 26 16 3.9 74.70 22,SE 12 5 31.5
H3P04-4%
Urea-10%+ N-4 66, P-I.89 25.7 4 1 73 10 5 5 3 34
H3P04-6%
Urea-10%+ N-4 66, P-2.52 36 4.1 69 02 4 ml 30 36
H3P04-8%
Urea-10%+ N-4 66, P-3.15 57 42 67 98 Nil ml 2 37 0
H3PO4-10%
Urea-20%+ N-9 32, P-1.26 15.7 4 74 71 15.SE 10.0 40 32 0
H3P04-4%
Urea-20%+ N-9.32, P-1 89 23 44 73.54 5, SE ml 25 345
H3P04-6%
Urea-20%+ N-9.32, P-2 52 34 3 42 70 22 Nil ml 1.5 38
H3P04-8%
Urea-20%-!- N-9 32, P-3 I5 40 42 67 99 Nil ml 1 0 38 5
H3PO4-10%
*BEL Burned entire length S E , Self Extinguishing

Journal of Polymer Materials June 2011

 156 A K Sarrianta et al

is further increased higher loss in fabric tenacity decreased with increase in concentration of
occurs. H3P04 in formulation 1, irrespective of
concentration of urea used.
These fire retardant finished jute fabrics also
suffers some loss in tenacity in case of
Effect of treatment with combination of
treatment with combination of urea and H,PO,.
This may be due to the acidic degradation by
Urea and Di Ammonium Phosphate (DAP)
H3P04 during curing. (Formulation-2)

The bending length of these fire retardant treated It is known from literature that diammonium
jute fabrics are found to be increased with the phosphate can be used as flame retardant for
increase in concentration of H3P04 causing the cotton cellulose as it lowers the combustion
fabric handle to become slightly stiffen The temperature, decreases weight loss rate and
stiffness so imparted is perhaps also due to increases residual char formation[17fThe
the effect of phosphorylation reaction used in changes in flammability and related textile
formulation-1 properties of jute fabrics after being treated with
formulation-2(DAP in varying amount viz.5%,
For the surface appearance properties, it is I0%, 15%, 20% with Urea 20%) have been
noticed that whiteness indices are found to be assessed and shown in Table 3.
TABLE 3 Physical and Fire Retardant properties of jute fabric treated with fire retardant Formulation-2 with Urea
and DAP

Treatments Calculated Physical properties Flammabiiayprop 5 rties

(Applied N% & P% Tensile Bending Surface 45° Inclined L O.l %
on weight (applied Properties Properties Appea­ Flammability test
of fabric chemicals) rance
Properties
% Loss Bending Whiteness Flame After Char Limiting
in Length Index Spread Glow Length Oxygen
Tenacity (cm) (Hunter) Time Time (cm) Index %
(sec) (sec)

Untreated Nil Nil 3.8 75 20 49.0 55.0 •BEL 20 5

(BEL*) (12 5)

Urea-20%+ N-10 38%, 23 39 73.64 18 12 6 32

DAP-5% P-1 17%

Urea-20%+ N-11.44%, 30 7 42 72 08 ml Nil 20 37.5

DAP-10% P-2 34%

Urea-20%+ N-12.50%, 33 42 71.95 ml Nil 1.5 38.0

DAP-15% P-3 51%

Urea-20%+ N-13 56%, 48 5 4.3 69.28 Hi! Nil 1.0 38.5

DAP-20% P-4 68%

•Burned entire length' S E ., Self Extinguishing.

’ Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabnc and its Thermal Behaviour using Phosphorous and 157
Nitrogen based Compound

DAP, ammonium salts of Phosphoric acid is decreases the amount of combustible volatiles
easier to use than direct use of H,PO, as the and causes a proportional increase in the
acidic degradation of celluloses are lesser in amount of char formation in cellulosics rendering
case of DAP. It is observed that for application fire retardant nature to the treated fabric
of 5% DAP and 20% urea, fire retardant
For surface appearance properties, it is noticed
performances are not up to the desired level
that whiteness indices are decreased with
(LOI-32). However, at 20% urea and 10% DAP
increase in DAP percentage applied in formulation-
treatment^ e calculated P-2.3%), showed
2 on jute fabrics. Bending length values are also
balance flame retardancy(LOI value-37.5 and
found to be increased with increase in DAP
char length-2cm )and loss in tenacity is
percentage keeping % urea fixed.
medium(30%) With further increase of DAP at
15%, LOI slightly increases to 38 0 with Effect of treatment with combination of
strength losses to 43% and at 20% DAP, LOI Thiourea and Diammonium phosphate
reaches to 38 5 and high loss in tenacity (Formulation-3)
occurred(48%). The optimum flame retardancy
is achieved for use of 10% DAP and 20% Urea Fire retardant performance ofjute fabrics treated
which might be attributed to a synergistic effect with mixture of varying concentration of
of DAP(P) and Urea(N). This combination diammonium phosphate (5%, 10%.and 15%

TABLE 4 Physical and Fire Retardant properties of jute fabnc treated with fire retardant ForiYiulation-3 with Thiourea
and DAP
| calculated Physical prop*erttes Flammability properties
Treatments
(Applied N% & P% Tensile Bending Surface 45° Inclined LO l.%
on weight content Properties Properties Appea- Flammability test
of fabric %) of applied ranee
chemicals Properties
% Loss Bending Whiteness Flame After Char Limiting
in Length Index Spread Glow Length Oxygen
Tenacity (cm) (Hunter) Time Time '(cm) Index %
(sec) (sec)

Untreated Nil Nil 38 75 20 49 0 55.0 *BEL 20.5

(BEL*) (12.5)
Thiourea 8%+ N-3 98%, 21.4 4.0 74 37 119 27 *BEL 27
DAP-5% P-1.7% (12 5)
Thiourea 8%+ N-5 04%, 27 4 25 71 19 11,SE ml 4 34
DAP-10% P- 2.34%
Thiourea 8%+ N-6.10%, 35 7 4.3 69 98 5, SE ml 3 35
DAP-15% P-3 51 %
Thiourea 10%+ N-4 71%, 20 4 25 74.94 123 27 *BEL 27.5
DAP-5% P-1.17% (12.5)
Thiourea 10%+ N-5.77%, 28.6 4.3 71 63 4, SE ml 3 35
DAP-10% P-2.34%
Thiourea 10%+ N-6.83%, 35 43 69 47 3, SE ml 2 36
DAP-I5% P-3 51 %
*BEL. Burned entire length. S E , Self Extinguishing

Journal of Polymer Materials June 2011

 158 A K Samanta et al

o.wf) and Thiourea having concentration of However, It is observed that Thiourea-DAP

(either 8% or 10% o w f.) have been evaluated combination showed somewhat lesser fire
and the resuits are shown in Table 4 Thio- retardancy property than Urea- H3P04 or Urea-
urea(NH2CSNH2), an organic compound, similar DAP combination but strength retention is
to urea except that the oxygen atom is better Loss of tenacity of Thiourea-DAP treated
replaced by a sulphur atom, is also used in fabric is 20-35%. Overall, 10% DAP and 10%
other textiles assuming that nitrogen
Thiourea showed balanced fire retardance
compounds having sulphur present contributes
property(LOI value 35) with loss of tenacity
to Phosphorous -Nitrogen synergism1141.
within 28.6%.
Relevant data in Table 4 indicate that there is
an increasing trend of LOI values, as the The bending length values are increased with
percentage application of DAP is increased the increasing percentage application of
with fixed concentration (8% or 10% o.w f.) of Thiourea-DAP treatment For the surface
thiourea . Maximum LOI of 36 is obtained for appearance properties it is noticed that
10% application of thiourea and 15% of DAP whiteness index are slightly decreased with
with loss of tenacity within 35%. Thiourea-DAP treatment

TABLE 5 Fire Retardant properties of jute fabric treated with fire retardant Formulation-4 with Dicyandiamide and
DAP

Treatments N% & P% Physical properties Flammability properties

(Applied content Tensile Bending Surface 45° Inclined L O l.%
on weight of applied Properties Properties Appea- Flammability test
of fabric %) chemicals as ranee
calculated Properties
% Loss Bending Whiteness Flame After Char Limiting
in Length Index Spread Glow Length Oxygen
Tenacity (cm) (Hunter) Time Time (cm) Index %
(sec) (sec)

Untreated Nil Nil 3.8 75 20 49 0 55 0 ‘BEL 20.5

(BEL*) (12.5)
Dicyandiamide N-6.26%, 20 42 71.00 110.SE 30 10 28
8%+DAP-5% P-1 17%
Dicyandiamide N-7 32%, 28 44 70 02 10,SE ml 40 34
8%+DAP-1 0% P-2 34%
Dicyandiamide N-8 38%, 30 44 70 72 8,SE ml 4 35
8%+DAP-15% P-3.51 %
Dicyandiamide N-7.56%, 18 42 72 48 85,SE 19 7 28.5
10%+DAP-5% P-1.17%
Dicyandiamide N-8 62%, 27 4.4 70.92 3 ml 3 36.5
10%+DAP-10% P-2.34%
Dicyandiamide N-9.68%, 30 45 70 87 2 ml 2 37
10%+DAP-15% P-3 51%
*BEL Burned entire length S E., Self Extinguishing

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 159
Nitrogen based Compound

Effect of treatment with combination of whiteness indices slightly deteriorated with the
Dicyandiamide and Diammonium DAP and dicyandiamide combination in
phosphate (Formulation 4) formulation-4 applied on jute fabrics

Fire retardant performance ofjute fabrics treated Effect of treatment with combination of
with the mixture of varying concentration of DAP- varying concentration of Pyrovatex CP
5%, 10% and 15% with fixed concentration of along with DMDHEU resin
Dicyandiamide(8% or 10% o wf) have been (Formulation 5)
evaluated and the results are shown in Table 5.
Pyrovatex CP, a commercial grade fire retardant
Dicyandiamide(C2H4N4),is the dimer of
agent, a reactive phosphorous compound (N-
cynamide and is known to be used earlier as a
methylol di methyl Phosphono-propionamide)
nitrogenous fire retarding agent along with
has been reported earlier to provide excellent
Phosphorous compound for P-N synergism in
fire retardant performance on cotton cellulose
cotton textiles1151. Relevant data in Table 5
in presence of N based crosslinking agent and
indicate that there is an increasing trend of LOI
phosphoric acid as catalyst111 To understand
values of treated jute fabrics with the increasing
the fire retardant performances of newer
concentration of DAP percentage for the fixed
combination of indigenous P-N chemicals as
concentration of dicyandiamide either at 8% or
compared to that obtained by Pyrovatex CP
10% o.w.f. The flame spread time, after glow
additional experiment were carried out with
time, char length are also found to be
different % of Pyrovatex CP. The changes in
accordingly decreased showing improved fire
important textile related properties ofjute fabrics
retardance performance. The balanced
after being treated with formulation-5 [Pyrovatex
improvement in fire retardancy performance(LOI
CP in varying amount viz. 10%, 15%, 20%,
36 5) is found with 10%(o wf.) concentration
25%, 30% with fixed concentration of
dicyandiamide and 10% concentration of DAP.
DMDHEU(Di methylol di hydroxy ethylene urea)-
Dicyandiamide alone does not improve much
8% and H3P04 -2% o.w.f as catalyst have been
fire retardancy, but in conjunction with
assessed and shown in Table 6. Data shown in
Phosphorous compound (DAP), this nitrogen
Table 6 indicate that there is a moderate to
compound (dicyandiamide) appear to enhance
noticeable improvement in fire retardance
the phosphorylation reaction to jute cellulose
performance by almost all the treatments with
and enhance the fire retardant performance. The
Pyrovatex CP (Formulation 5) as indicated by
fabric tenacity values also show a decreasing
LOI values, flame spread time, after glow time
trend with increase in concentration of DAP
and char length. The fire retardance performance
concentration, however the loss of tenacity is
is increased with increase in concentration of
within 20-30% i.e. strength retention is
Pyrovatex CP in Formulation 5. Highest value
somewhat better in case of Dicyandiamide
of LOI 37 is achieved with 30% application of
use(minimizes the acidity) .The bending length
Pyrovatex CP and the flame spread time, after
values show increasing trend with increase in
glow time and char length are also found to be
the application percentage of the DAP.
decreased accordingly with 51% loss in fabric
From the surface appearance properties, tenacity There is always some loss in tensile

Journal of Polymer Materials June 2011

160 A K Samanta et a!

TABLE 6 Physical and Fire Retardant properties of jute fabric treated with Pyrovatex CP and DMDHEU-resin

Treatments Physical properties Flammability properties

(Applied on weight Tensile Bending Surface 45° Inclined LO I%
of fabric %) Properties Properties Appea­ Flamnability test
rance
Properties
% Loss Bending Whiteness Flame After Char Limiting
in Length Index Spread Glow Length Oxygen
Tenacity (cm) (Hunter) Time Time (cm) Index %
(sec) (sec)
Untreated - 38 75 20 49 0 55 0 ‘BEL 20 5
(BEL*) (12.5)
Pyrovatex CP-10%+Resm“ 31 4 1 73.55 120 10 0 5.0 29.0

Pyrovatex CP-15%+Resin“ 33 6 42 70.58 4 4.0 30 31 0

Pyrovatex CP-20%+Resin 38 42 68 96 2 0.SE 2 2.0 33 5

Pyrovatex CP-25%+Resin“ 40 43 68 98 2, S E Nl 2.0 36 0

Pyrovatex CP-30%+Resin" 51 43 68 92 ml Nil 2 37 0

*BEL: Burned entire length. S.E , Self Extinguishing

“DMDHEU-resin 8% and H3PQ4 2%

strength for all the treatments using formulation solution for 30 minutes at room temperature,
5 The loss of tensile strength is found to the fire retardancy performance is found to be
increase with the increase in the percentage decreased after washing (Table 7). Hence, this
application. Fabric also becomes stiffer for the type of fire retardant formulation is not durable/
treatment having formulation 5, as the bending permanent type; the LOI values decreased by
length values are found to be increased as usual about 20-30% and hence can be used as a semi
with the increase in percentage application of permanent flame retardant. The wash stability
Pyrovatex CP in Formulation 5. Whiteness of Urea- H3P04 or Urea-DAP is slightly better
indices are only marginally deteriorated with than Thiourea-DAP and Dicyandiamide-DAP
Pyrovatex CP treatment in Formulation 5 for treated fabric. It is assumed that H3P04 or DAP
jute fabrics. form some ester linkage with jute cellulose in
presence of urea and the degree of
Wash stability of different fire retardant phosphorylation is higher in presence of urea,
treated jute fabrics while the same is somewhat lower in case of
While flame retardancyof many of the Nitrogen- dicyandiamide and lowest in case of thiourea.
Phosphorous based formulation are good, but Pyrovatex CP is though costly fire retardant
the wash stability was not necessarily good. chemicals, its wash stability to some extent
After normal washing of this fire retardant treated superior to all other fire retardant used but
jute fabrics with 0.1% non ionic detergent Pyrovatex CP along with DMDHEU resin and

Journal of Polymer Matenals June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 161
Nitrogen based Compound

TABLE 7 Flammability property of the different fire retardant treated fabric at the optimized level after soap
washing

Treatment LOI-vaiue Before LOI -value after Soap

(Applied on weight Soap Washing Washing
of fabric %) 1st wash 2nd wash 3rd wash
Urea-20%, 38 31 30 29
H3P04-8%
Urea-20%, 37 5 29 28 5 27
DAP-10%
Thiourea-10% 35 27 26 25
DAP-10%
Dicyandiamide-10% 36 5 29 27 26
DAP-10%
Pyrovatex CP-25% 36 31 30 29

H3P04 catalyst show much higher strength loss

of jute and chemically treated jute samples are
than all other fire retardant chemicals used.
shown in Fig. 2,3 respectively. The effectiveness
Study of surface morphology of fire of phosphorylation of cellulosic material may
retardant jute fibres be indicated by substantial lowering of the
decomposition temperature as well as higher
The scanning electron micrograph study of fibre
char formation compare to the untreated
surface appearance of bleached and different
fabric1161 TGA analysis of jute fabric treated with
fire retardant treated jute fabrics is shown in
nitrogen and phosphorous based fire retardant
Fig. 1 (a-f).SEM -photographs of bleached jute
chemicals(formulations 1 to 4) show that
fabric (Fig. 1a) showed that surfaces were
residue left at 500°C is more than that of
smooth where as fire retardant treated fabric
untreated jute. Among the different treated fabnc,
(formulation 1 to 5) showed some small cavities
It can be shown Urea(20%) and H3P04(8%)
were present causing some loss in strength.
treatment leaves highest residue(36.5%) or
The amount of cavity is more pronounced in
weight loss is minimum where as untreated jute
case of urea-H3P04 (Fig. 1b) and urea-DAP
leaves a residue of only 10%. Therefore, this
(Fig. 1 c) treated jute fabric where as in case of
combination is expected to give best fire
thiourea-DAP (Fig. Id) and dicyandiamide-
retardant property116’17'18'191. The LOI value and
DAP(Fig. 1e) treated fabric the amount of cavity
45° flammability test results also confirm this
is less causing lesser amount of strength.
observation. Urea(20%) and DAP(10%)
Thermal analysis of treated and treatment also leaves a residue of 36%
untreated jute fabric (2nd highest) at 500°C which is also matched
with the observed higher flame retardant
Thermogram 2 for Thermo-Gravimetric Analysis
properties.
(TGA) in air and thermogram 3 for Differential
Scanning Calorimetric(DSC) study in nitrogen Residue left for Dicyandiamide(10%) and

Journal of Polymer Materials June 2011

 162 A K Samanta et a!

> 3 UU Inu*' 8001103

Micrograph 1 (a) Micrograph 1 (b)

Micrograph 1 (c) Micrograph 1 (d)

13k<J XS0O OflQQlO 1 ?Vkr X30i> Utd^N (tOOOU

Micrograph 1 (e) Micrograph 1 (f)

Fig. 1 (a-f)' SEM micrographs showing surface morphology of (a) Untreated bleached jute, (b) Urea and H3P04
treated jute (c) Urea and DAP treated jute (d) Thiourea and DAP treated jute (e) Dicyandiamide and DAP
treated jute and (0 Pyrovatex CP treated jute

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 163
Nitrogen based Compound

W eight (%)

Temperature ( C)

Fig 2. Thermogravimetric analysis Thermograms of a) Scoured Jute b) Urea + Phosphoric acid treated jute c)Urea
+ DAP treated jute d) Thiourea + DAP treated jute e) Dicyandiamide+DAP treated jute

Fig 3 Differential Scanning Calorimetnc Thermograms of a) Scoured Jute b) Urea treated Jute c) Phosphoric Acid
treated Jute d) Urea+PhosphoricAcid treated Jute

Journal of Polymer Matenals June 2011

164 A K. Samanta et al

DAP(10%) treatment is 35% which also signified Dicyandiamide-DAP shows m.d t is 280°C and
high level of fire retardancy, However, jute fabric for Thiourea-DAP it is 275°C
treated with Thiourea and DAP showed residue
The major degradation or pyrolysis temperature
of 30% which is somewhat lesser than other
of the treated fabric ranged to around 280-300°C
treatments This can be explained by lesser
which was much lower than that for untreated
extent of phosphorylation occurred as
fabrics(major degradation temperature of
compared to other treatments.
untreated jute is 364°C) This can be explained
From the thermo-gravimetric curve, the major by the action of phosphorylation which alters
degradation temperature(m.d t) of untreated jute the decomposition route of jute constituents
and phosphorylated jute (formulation 1 to4)are forming lesser amount of volatile product with
also shown TGA-thermogram of Urea- H3P04 increasing char formation and LOI values'18-191.
shows major degradation temperature is
DSC thermogram 3(a) for control jute shows
290°C, TGA-thermogram of Urea-DAP shows
broad endothermic peak at 80°C (for evaporation
major degradation temperature is 285°C,
Absorbance %

4000 3000 2000 1000 500

Wave number (cm'1)

Fig 4 FTIR-spectra of (a) Bleached Jute (b) Urea & H3P04 treated Jute (c) Urea and DAP treated Jute

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabnc and its Thermal Behaviour using Phosphorous and 165
Nitrogen based Compound

of moisture present in jute), a broad exotherm and exothermic peak at 430°C due to
with a hump at 293°C (for degradation of degradation of lignin part
hemicellulose part of jute), a sharp endotherm
FTIR-Spectroscopic study
i e. peak at364°C (for degradation of cellulose
component of jute) and a broad exotherm with FTIR-spectra of bleached jute and fire retardant
small hump at 425°C (for degradation of lignin treated jute are shown Figs 4 and 5 respectively.
part of jute) which corroborates earlier findings The spectra of bleached jute (Fig. 4a) showed
of thermal behaviour study of control jute by characteristics broad peaks at 3610 (-OH-
DSC and TGAI67l stretchmg), 1736(-CO-stretching), 2893(-CF1-
stretching), 1736(-CO-stretching) and 2893
DSC thermogram 3(d) for Urea-H3P04, treated
(CFI-stretching)E7'181
jute shows endothermic peak at 71 °C (Moisture
evaporation), exothermic peak at 290°C may Urea and H3P04 treated jute fabric (Fig. 4b),
be associated with degradation of cellulose part phosphorylation led to emerging peak 1304 cnr1

4000 3000 2000 1000 500

Wave number (cnr1)

Fig 5. FTIR-spectra of (d) Thio-urea & DAP Jute (e) Dicyandiamide & DAP treated Jute (f) Pyrovatex CP treated Jute

Journal of Polymer Materials June 2011

166 A K Samanta et al

TABLE 8 Changes in band intensity of FTIR-spectra of bleached and FR treated Jute Fabric

Sample Position of Nature/area Change of functional group

band (cm-1) of Band pattern
923 Small Peak b- glycosidic linkage

1027, 1111 Small Peak -OH-stretching

I Small Peak
1257 -C-O-C-Stretching

Bleached 1404, 1597 Small Peak -CH-stretchmg

Jute 1736 Medium Peak -CO-group stretching

2145,2393 Small Peak -CH-stretching

3214 Small Peak -CH2 stretching

3610 Strong Peak -OH -group(free)

903 New Broad Peak -C-O-P stretching

1304 Small Peak P=0 stretching

Urea & 1589 Medium Peak -CH stretching

Phosphoric 1732 Medium Peak -CO stretching

Acid treated 1853 Small Peak - NH4 stretching

Jute 2399 Medium Peak -CH2 stretching

3433 Small Peak NH-stretchmg

3664 Small Peak OH stretching(some-OH-group is blocked due

to Phosphorylation).

855,893 New Peak -C-O- P stretching

1295, 1349 Medium Peak P=0 stretching

1588 Small Peak -CH stretching

Urea & 1732 Medium Peak -CO-group

DAP 1811 Small Peak - NH4 stretching

treated Jute 2182,2392 Small Peak -CH2 stretching

3470 Small Peak NH-stretchmg

3704 Small Peak -OH stretching(some-OH-group is blocked due

to Phosphorylation)

Journal of Polymer Materials June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 167
Nitrogen based Compound

TABLE 8 Contd .

Sample Position of Nature/area Change of functional group

band (cm-1) of Band pattern

863 New Peak -C-O-P stretching

1295, 1349 Medium Peak P=0 stretching

Thio- 1410 Small Peak -CH stretching

Urea & DAP 1727 Medium Peak -CO-group

treated 1811,1858 Small Peak - NH4 stretching

Jute 2396 Small Peak -CH-stretching

2946,2986 Small Peak -CH-stretching

3570,3710 Small Peak -OH stretching

849 New Peak -C-O-P stretching

Dicyandi 1296 Small Peak P=0 stretching

amide & 1728 Medium Peak -CO-group

DAP treated 1813 Small Peak - NH4 stretching

Jute 2230,2399 Small Peak -CH-stretching

3533 Small Peak -OH stretching(some-OH-group is blocked due

to Phosphorylation)

Pyrovate 871 New Peak -C-O-P stretching

x CP treated 1859 Medium Peak -CO-group treated

Jute 3502,3786 Small Peak -OH stretching(some-OH-group is blocked due

to Phosphorylation)

which can be attributed to P=O stretching from CONCLUSIONS

phosphate, a broad absorbance peak at
1. The present study also showed that different
903 cm_1 was observed and was assigned to
formulations or different add-on can impart
the C-O-P stretching in the phosphate
different extent of flame retardancy performance
ester120 21'221. Decrease in absorbance region in on jute fabric using different types of
3600 cm-1 also suggest phosphorylation of Phosphorous and Nitrogen based fire retardant
hydroxyl group. The detailed changes in band compounds. The efficiency of fire retardancy has
or peak intensity of FTIR- spectra of bleached been shown dependent of the Phosphorous
and FR treated Jute fabric are shown in Table content of the treated material and a minimum
8 The IR spectral analyses also support the of 2.5% of phosphorous is necessary.
existence of such structures for Nitrogenous compounds also help to reduce
phosphorylated cellulose. flame retardancy as well as strength retention.

Journal of Polymer Materials June 2011

168 A K Samanta et al.

2 All the N-P based formulations showed 'Development of fire retardant jute fabric’ during
sufficiently effective fire retardant properties 2008-2011
The order of effectiveness is as follows.

Urea and H.PO. 3 4

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Journal of Polymer Matenals June 2011

 Fire Retardant Finishing of Jute Fabric and its Thermal Behaviour using Phosphorous and 169
Nitrogen based Compound

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RECEIVED • 20 September 2010

ACCEPTED 20 April 2011

Journal of Polymer Materials June 2011