Editorial Feature

How Do Polymers Degrade?

Polymers have become an integral part of our daily lives, encompassing a wide range of materials from plastic bottles to synthetic fibers. However, have you ever pondered the fate of these polymers over time?

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Image Credit: Kuttelvaserova Stuchelova/Shutterstock.com

In this article, we embark on a fascinating journey through the field of polymer degradation, unraveling the intricate processes behind their breakdown, the factors that influence this degradation, and the consequential real-world impacts.

What Does Polymer Degradation Mean?

When we speak of polymer degradation, we refer to the gradual breakdown of polymers, such as plastics, resulting from exposure to various environmental factors like heat, light, oxygen, etc. This deterioration can lead to the loss of desirable properties such as strength and flexibility.

Let us look at the diverse mechanisms involved in polymer degradation, each characterized by distinct processes that ultimately culminate in the fragmentation of polymer chains into smaller constituents.

What are the Different Ways Polymers Degrade?

The degradation of polymers can happen through several distinct mechanisms, each contributing to the eventual breakdown. These mechanisms encompass:

Thermal Degradation

Subjecting polymers to elevated temperatures causes the bonds between individual polymer chains to weaken and break, resulting in the formation of smaller molecules. The presence of oxygen or other oxidizing agents can accelerate this process, exacerbating the degradation process.


The exposure of polymers to ultraviolet (UV) radiation initiates a chain reaction that instigates the breakdown of polymer chains. This occurs primarily through the generation of free radicals, which induce the degradation process.


When polymers come into contact with water, the bonds between individual polymer chains can undergo cleavage, leading to the formation of smaller molecules. This hydrolytic process contributes significantly to polymer degradation.


Certain polymers possess inherent susceptibility to degradation by biological organisms, such as bacteria, fungi, or algae. These organisms produce enzymes that facilitate the cleavage of polymer chains through enzymatic reactions, thus aiding in the degradation process.

Chemical Degradation

Polymers can engage in chemical reactions with various substances prevalent in the environment, such as acids, bases, and solvents. These interactions instigate degradation, gradually compromising the structural integrity of the polymers.

What Affects Polymer Degradation?

Polymer breakdown can be influenced by an array of factors, encompassing temperature fluctuations, the presence of oxygen, exposure to UV radiation, and the inherent structure of the polymer itself.


Temperature undeniably exerts a profound impact on the degradation process, with higher temperatures hastening the breakdown while lower temperatures impede it. Fluctuations in thermal conditions can either accelerate or decelerate the degradation of polymers.


When polymers come into contact with oxygen, they engage in oxidation reactions, which are expedited by the presence of oxygen molecules. Consequently, polymers are prone to degradation when exposed to air due to these oxidation reactions.

Ultraviolet (UV) Radiation

UV radiation, especially sunlight, poses a formidable threat to polymers. Exposure to UV radiation renders polymers considerably more vulnerable to breakdown, as it triggers a process known as photooxidation.

The energy provided by UV radiation sets off a chain reaction that disintegrates the polymer chains, leading to degradation. This is why plastics left outdoors, such as those used in outdoor furniture or garden hoses, progressively deteriorate due to prolonged exposure to sunlight.

Polymer Structure

The structure of a polymer itself plays a pivotal role in its susceptibility to degradation. The chemical composition and arrangement of polymer chains dictate the ease with which the polymer can degrade.

Polymers featuring more reactive functional groups or weaker bonds are particularly prone to degradation. For instance, polymers containing ester or amide linkages, like polyesters and polyamides, are susceptible to hydrolysis. In hydrolysis, water molecules react with the polymer chains, leading to their fragmentation.

The Role of Stabilizers and Resistance Mechanisms in Polymer Degradation

To combat polymer degradation, stabilizers are frequently incorporated during the manufacturing process. These compounds function by scavenging free radicals, absorbing UV radiation, or acting as antioxidants. Hindered phenols, UV absorbers, and metal deactivators are among the common types of stabilizers employed.

Furthermore, certain polymers possess inherent resistance to degradation owing to their chemical structure. For instance, high-density polyethylene (HDPE) and polypropylene (PP) exhibit exceptional resilience against thermal and UV degradation. Consequently, they are well-suited for applications exposed to outdoor environments.

The Significance of Polymer Degradation

Polymer degradation has wide-ranging effects on the environment, human health, and the mechanical strength of polymer structures. For example, the accumulation of microplastics resulting from polymer breakdown threatens aquatic ecosystems and marine life.

Chemicals released during degradation, like phthalates, have been linked to health issues. Moreover, the loss of mechanical strength in degraded polymers compromises the performance and safety of various products.

However, when controlled, polymer degradation can bring benefits. For example, it allows for the development of biodegradable polymers that naturally break down, reducing plastic waste. Controlled degradation is also crucial in drug delivery systems, ensuring the slow and effective release of medications.

Additionally, polymer degradation aids in recycling and waste management by simplifying processing and resource recovery. It can even assist in environmental cleanup by degrading pollutants or encapsulating hazardous chemicals. Exciting research is being conducted on self-healing polymers, enhancing material durability, and offering new possibilities for long-lasting solutions.


Polymers can degrade through various mechanisms, including thermal degradation, photo-oxidation, hydrolysis, biodegradation, and chemical degradation. Factors such as temperature, oxygen exposure, UV radiation, and polymer structure influence the rate and extent of degradation.

While polymer degradation is often associated with environmental challenges and material deterioration, there are also potential benefits when it is controlled and intentional.

Biodegradable polymers can reduce plastic waste, controlled drug delivery systems enhance medication effectiveness, and polymer degradation aids in recycling and waste management. Additionally, polymers can be utilized in environmental cleanup and self-healing materials.

However, careful consideration of the environmental impacts and the balance between durability and degradation is necessary for sustainable development and resource conservation in the polymer industry.

More from AZoM: How are Bioplastics Made?

References and Further Reading

Coolmag Blog. (2022). What is polymer degradation? [Online]. Coolmag. URL https://coolmag.net/what-is-polymer-degradation/ (accessed 6.8.23).

Goyal, M., Agarwal, S.N., Bhatnagar, N. (2022). A review on self-healing polymers for applications in spacecraft and construction of roads. Journal of Applied Polymer Science. 139, e52816. https://doi.org/10.1002/app.52816

Vohlídal, J. (2021). Polymer degradation: a short review. Chemistry Teacher International. 3, 213–220. https://doi.org/10.1515/cti-2020-0015

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.

Blaise Manga Enuh

Written by

Blaise Manga Enuh

Blaise Manga Enuh has primary interests in biotechnology and bio-safety, science communication, and bioinformatics. Being a part of a multidisciplinary team, he has been able to collaborate with people of different cultures, identify important project needs, and work with the team to provide solutions towards the accomplishment of desired targets. Over the years he has been able to develop skills that are transferrable to different positions which have helped his accomplish his work.


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