UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO
ESCUELA NACIONAL PREPARATORIA
PLANTEL No. 6 “ANTONIO CASO”
Ciclo Escolar: 2024-2025
Grupo: 603A
Profesora: Maria Mercedes Camacho Reyes
"Biodegradable polymers and their impact on reducing plastic waste"
GONZÁLEZ JIMÉNEZ EDWIN MICHEL
323216898
GONZÁLEZ GÓMEZ ELIAS ARMANDO
323161389
NEGRETE RODRIGUEZ ADRIAN
323061399
FONSECA MEZA JESUS MAURICIO
323120988
OBJECTIVES
1. Analyze the physical, mechanical, and thermal properties of various types of
biodegradable polymers, such as PLA, PHA, and other starch derivatives, to
assess their suitability for industrial applications.
2. Investigate the degradation mechanisms of polymers in different
environments (soil, water, and industrial composting) and determine the
factors affecting the rate of degradation, such as temperature, humidity, and
the presence of microorganisms.
3. Compare the environmental impact of biodegradable polymers versus
conventional plastics in terms of carbon emissions and energy efficiency in
the production process.
4. Explore current and potential applications of biodegradable polymers in key
industries such as food, textiles, and automotive, as well as their market
acceptance and perception by consumers and businesses.
PURPOSE
The purpose of this research is to contribute to the development and optimization of
biodegradable polymers as a sustainable solution for reducing plastic waste, exploring their
properties, challenges and applications. By better understanding the behavior and limitations
of these materials, we seek to promote their adoption in the industry and encourage
responsible practices that minimize environmental impact, thus facilitating the transition
towards a circular and sustainable economy.
INTRODUCTION
In recent decades, plastic pollution has become one of the main environmental challenges
worldwide. The mass production of petroleum-derived plastics has led to the accumulation of
waste in oceans, rivers and landfills, generating a negative impact on ecosystems and
human health. Faced with this problem, biodegradable polymers have emerged as a
potentially viable solution to reduce the amount of persistent plastic waste in the
environment.
Biodegradable polymers are materials designed to decompose under natural conditions or in
industrial composting facilities, transforming into organic compounds such as carbon dioxide,
water and biomass. Unlike conventional plastics, which can take centuries to degrade, these
polymers have the ability to decompose in a significantly shorter period, depending on
environmental conditions and the type of polymer. Common examples include polylactic acid
(PLA) and polyhydroxyalkanoates (PHA), both derived from renewable resources.
However, the mass implementation of biodegradable polymers is not without challenges.
Production costs, mechanical and thermal properties that often do not match the
performance of conventional plastics, as well as the specific conditions required for their
biodegradation, raise questions about their feasibility and real effectiveness in reducing
waste. It is therefore crucial to research and develop new formulations that improve the
characteristics of these materials, as well as to assess their environmental impact compared
to traditional plastics.
Methodology
Biodegradable polymers can be categorized based on their origin into three main types:
1. Natural-based Polymers
Derived from renewable biological resources such as plants or animals. Common examples
include starch, cellulose, and chitosan.
Polylactic Acid (PLA): A well-known biodegradable polymer, derived from corn starch or
sugarcane, widely used in packaging and disposable products.
2. Synthetic Biodegradable Polymers
Produced chemically, yet designed to break down in natural environments. Examples include
aliphatic polyesters and polyhydroxyalkanoates (PHA), the latter produced by bacteria.
Polycaprolactone (PCL): A synthetic polyester that degrades under industrial composting
conditions.
Hybrid Polymers
Combine natural and synthetic components to enhance both mechanical properties and
biodegradability. PLA reinforced with starch is a common example.
3. Biodegradation Processes
Biodegradation refers to the breakdown of polymers into simpler compounds such as carbon
dioxide, water, and biomass by microorganisms. Key mechanisms include:
Aerobic Degradation: Occurs in the presence of oxygen, resulting in carbon dioxide (CO₂),
water, and biomass.
Anaerobic Degradation: Takes place in oxygen-free environments, producing methane (CH₄)
in addition to CO₂, water, and biomass.
Composting: Some polymers, like PLA, degrade efficiently in controlled composting
environments, where heat and moisture accelerate the process.
4. Comparison with Conventional Plastics
Degradation Time: Biodegradable polymers can break down in months or years under
appropriate conditions, while conventional plastics can last for hundreds of years.
Environmental Impact: Properly managed biodegradable polymers decompose into non-toxic
byproducts, whereas traditional plastics fragment into microplastics that persist in
ecosystems.
Cost and Availability: Although
RESULTS
Compared with other aliphatic polyesters, PLA has demonstrated many excellent properties,
such as high strength and mechanical modulus, biodegradability, biocompatibility, and easy
processing. The increasing application of PLA is also related to the improvement of its
properties, such as heat resistance modification, copolymerization, and blend modification.
This table compares PLA (polylactic acid) with PHA (polyhydroxyalkanoates) and PBAT
(polybutylene adipate terephthalate), showing key differences in their properties and
applications.
Propiedad PLA PHA PBAT
Mechanical resistance High Moderate High
Module High Low Moderat
e
Biodegradability Yes Yes Yes
Biocompatibility Yes Yes No
Ease of processing Simple Moderate Hard
Heat resistance Improvable High Moderat
e
Copolymerization Possible Limited Possible
Modification of mixtures Common to improve properties Less Common
common
PHA biodegradation
Microorganisms produce PHAs and therefore have enzymes that can biodegrade PHAs.
These are PHA depolymerases that break the polymer chain by hydrolysis of the ester
bonds. This results in oligomers and monomers that dissolve in water. In one study, at 58oC
and pH 8.2, all PHA samples showed 15 to 25% degradation after 15 days. After 70 days, all
PAH samples were degraded by 80 to 90%. The actual degradation rate varied depending
on the type of PAH, as shown in Table 1.
PHA Degradation after 70 days
PHBV-40 95%
PHBV-2 89.3%
PHB-3 80.2%
PHB 79.7%
P (3HB,4HB) 90.3%
PLA biodegradation
The biodegradation mechanism of PLA occurs in two stages; hydrolysis of ester bonds to
form lactic acid oligomers and then digestion of the oligomers by microorganisms. CO2 and
water are produced in the process. Because microorganisms are not known to produce PLA,
the first stage of biodegradation is not easily mediated by microorganisms. Therefore, it is
necessary to create special conditions such as pH and temperature to help the degradation
of PLA.
Temperature Biodegradation
37oC 20% after 12 months
45oC 57% after 9 weeks
CONCLUSIONS
Research on biodegradable polymers highlights their potential as a sustainable solution to
mitigate plastic pollution. Through the analysis of its properties and challenges, such as the
cost of production and effectiveness in specific environmental conditions, it seeks to facilitate
its adoption in the industry. Materials such as polylactic acid (PLA) and
polyhydroxyalkanoates (PHA) show advantages in biodegradability and mechanical
properties, although their implementation still faces barriers. In conclusion, the development
and improvement of these polymers are essential to move towards a circular economy, thus
minimizing the environmental impact of conventional plastics.
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Jesus. (2024, 12 junio). PLA y PLLA. Polimerbio. https://polimerbio.com/pla-plla/
If, A. (2023, 28 septiembre). La biodegradación de los bioplásticos a base de PHA, PLA y
almidón varía con la formulación. Venvirotech.
https://venvirotech.com/comparar-biodegradabilidad/
Greenpeace España. (2021, August 23). Los bioplásticos no solucionan la contaminación por
plásticos - ES | Greenpeace España. ES | Greenpeace España.
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https://primebiopol.com/usos-y-aplicaciones-de-los-polimeros-biodegradables
