Addition Polymerisation

of of
→
Polymer : A
long chain molecule made up repeating units monomer .

Repeat Unit
W ✗

f- f c-]
✗
Wy =D + e-
1 I
n >

{
c-
'
y z f n

Monomer -

any alkene
Polymer

A double bond between the carbon breaks and it opens up

to form the
carbon bond
single .

" ' ' H

f- of
j II
H '
"
I
\c=c / 1
n → c- -
c- c-
/ It, I 1 I 1
H H H h H H
ethene

unit
polylethene) repeating

CH H
H
"
TH3 }

f- if if
H3T / l l
n , = , → e- -
c- c -
'
Y, I
t t
H

propane n µ
repeating unit
Poly ( propane)

at " a H
C'
,H

f. -1oh
I 1
,
d-d
g-
→
Yo
-

, /
"
I,
I , H H

polyvinyl chloride) repeating unit

vinyl chloride
Cchloroethene)
polylchloroethe.me

or C6

11¥ H
¥ it

t.I-I.tn
"
'
h \c=c →
-
C -
C -

+ ÷ i. a

styrene polylstyrene repeating unit

therefore
-

Polymers are inert and do not

biodegrade .

Why are polymers unreactive ( inert ) ?

they only
-

contain carbon carbon bonds ( saturated )

single
-
.
 The
magnitude of '
intermolecular exceed those between
polymers forces can
vastly
small molecules ,

*
f- CH2 -
CH
] f. CHA -
CH >
In
h

permanent dipole dipole Van der Waals

-
•

-
Van der Waals

Properties of polymers
" '' ¥1
%
,

I" 'I /E - x -- -

Difference material
in
branching on
polymer property

'

Longer chains with fewer branches have stronger intermolecular forces ,

making these
polymer materials

and
stronger more
rigid
.

branches difficult for chains closely form weak

Large make it to
pack together they only
•

, so

der Waals forces

②
van
.

:)
CH2 1-1

⇐ of
CH __
I

n
→

'
I H H
wander Waals forces
strong and
hence strong benzene
in polythene ,
ring is
it
rigid a
large branch , making
difficult for chain -1s to

pack
closely together .

Poly ( chloroethene) ( PVC ) %,

taobao.EE#-PolylchloroetheneJ ,
also known as PVC , is an addition
polymer formed from ehloroethene monomers .

toµ of i
'
" "

n y=f > -

,
H It H di .

?
Why is PVC hard but brittle

Permanent dipole dipole forces formed between chains between the 8- chlorine atoms
are
polymer
-

charge
-

on

the ft atoms
and
charges on carbon .

CI
as -

g-
• µ
THE
jis §
's -
-
 Modifying plastics using plasticise.rs

Plastic isers small molecules that

get between the polymer forcing them and
→ are
chains apart
slide
allowing them to across each other .

Plasticisers reduces strength of intermolecular forces between chains ,

making them more flexible .

Recycling of Plastics %
"E -x x x x -

Mechanical
Recycling

Plastics separated into different

types
•

are
.

→ washed

→ Sorted
→ Ground into pellets

/ [ remoulded
can be
melted

Feedstock
Recycling

Polymer chains heated to

high temperature and chains break down
'

Make new plastics .

7 monomers

Problems

Thermoplastic polymers be softened heated

-

= can when so can be melted + reused .

Some chains break become

may so shorter and properties might change
.

Isotactic :
side ( more desirable properties)
CH3 groups on same

Syndio tactic :
CH3 groups alternate sided

A-tactic Random (most outcome)

likely
: