Why Are Polymers Non-Biodegradable?

Plastics surround us. From water bottles and packaging materials to parts in cars and electronics, plastics have become essential in our daily lives. But their widespread use comes at an environmental cost – plastics pile up in landfills and oceans because most plastics do not biodegrade. So why exactly are polymers, the building blocks of plastics, resistant to breaking down naturally?

If you’re short on time, here’s a quick answer: Polymers such as polyethylene and polypropylene are non-biodegradable because their carbon-carbon backbone structure is too stable and inert for most microorganisms to metabolize and break apart.

What are polymers and how are they made?

Polymers are large molecules made up of repeating units called monomers. These molecules can be found in various forms and have a wide range of properties. They are used in a variety of applications, including plastics, rubber, fibers, and adhesives. Polymers can be either synthetic, meaning they are man-made, or natural, such as proteins and DNA.

Definition of polymers

A polymer is a macromolecule composed of repeating subunits called monomers. The word “polymer” comes from the Greek words “poly,” meaning many, and “meros,” meaning part. When these monomers join together, they form long chains or networks, creating the polymer structure.

How polymers are synthesized

Polymers can be synthesized through a process called polymerization. There are two main types of polymerization reactions: addition polymerization and condensation polymerization.

In addition polymerization, monomers with unsaturated bonds, such as ethylene or styrene, react together to form a polymer chain. This process involves the breaking of double bonds and the formation of new bonds between monomers. The reaction is initiated by a catalyst or heat.

In condensation polymerization, monomers with functional groups, such as carboxyl and amino groups, react together while releasing small molecules, such as water or alcohol. This reaction occurs through the formation of covalent bonds between monomers, leading to the growth of the polymer chain.

Types of polymerization reactions

There are several types of polymerization reactions, including:

  • Chain-growth polymerization: In this type of reaction, the polymer chain grows by the repeated addition of monomers to the active site of a growing chain.
  • Step-growth polymerization: This reaction involves the simultaneous reaction of two or more monomers, resulting in the formation of covalent bonds between them.
  • Copolymerization: Copolymers are polymers made by the polymerization of two or more different monomers. This process allows for the combination of different properties and characteristics in a single polymer.

Understanding the synthesis of polymers provides insight into their structure and properties. By manipulating the polymerization process, scientists can create polymers with specific properties for different applications.

Factors affecting biodegradability of polymers

Molecular weight

Molecular weight is an important factor that affects the biodegradability of polymers. Generally, polymers with higher molecular weights take longer to degrade compared to those with lower molecular weights. This is because larger polymer chains are more difficult for microorganisms to break down. For example, polyethylene, which has a high molecular weight, is known to be highly resistant to biodegradation. On the other hand, polyethylene glycol, with a lower molecular weight, is more easily biodegradable.

Branched vs linear structures

The structure of a polymer also plays a role in its biodegradability. Polymers with linear structures tend to be more biodegradable compared to those with branched structures. This is because microorganisms can easily access the linear chains and break them down. In contrast, the branched structures present more barriers for microbial action, leading to slower degradation. For example, linear polyethylene is more biodegradable than branched low-density polyethylene (LDPE).


Crystallinity is another factor that affects the biodegradability of polymers. Polymers with high crystallinity, such as polyethylene terephthalate (PET), have tightly packed chains that are difficult for microorganisms to access and break down. As a result, these polymers have low biodegradability. On the other hand, polymers with low crystallinity, such as polyvinyl chloride (PVC), have less ordered structures, making them more accessible to microorganisms and therefore more biodegradable.

It is important to note that the biodegradability of polymers is a complex issue influenced by various factors, including environmental conditions and the presence of specific microorganisms capable of degrading certain polymers. Therefore, it is crucial to carefully consider the characteristics of polymers and their potential impact on the environment before their widespread use.

Common non-biodegradable polymers and their uses

Polyethylene (PE)

Polyethylene is one of the most widely used non-biodegradable polymers. It is commonly found in products such as plastic bags, bottles, and packaging materials. The versatility and durability of polyethylene make it a popular choice in various industries. However, its non-biodegradability poses a significant environmental concern.

Polypropylene (PP)

Polypropylene is another non-biodegradable polymer that is commonly used in packaging, textiles, and automotive parts. Its resistance to heat and chemical solvents makes it suitable for a wide range of applications. Unfortunately, its non-biodegradable nature means that it persists in the environment for hundreds of years, contributing to the growing issue of plastic pollution.

Polystyrene (PS)

Polystyrene, often referred to as Styrofoam, is widely used in the foodservice industry for its insulating properties. It is commonly found in disposable cups, plates, and packaging materials. Despite its convenience, polystyrene is non-biodegradable and can take centuries to decompose. Its lightweight nature also makes it prone to littering and causing harm to wildlife.

Polyvinyl chloride (PVC)

Polyvinyl chloride, commonly known as PVC, is a versatile non-biodegradable polymer used in construction, electrical insulation, and various consumer products. Its durability, low cost, and resistance to fire make it a preferred choice in many industries. However, the production and disposal of PVC contribute to the release of toxic chemicals, posing health risks to both humans and the environment.

Polytetrafluoroethylene (PTFE)

Polytetrafluoroethylene, commonly known as Teflon, is a non-biodegradable polymer known for its non-stick properties. It is widely used in cookware, electrical insulation, and industrial applications. While PTFE is highly resistant to heat and chemicals, its non-biodegradability means that it accumulates in the environment, posing potential risks to ecosystems and wildlife.

It is important to note that the non-biodegradability of these polymers stems from their chemical structure, which makes it difficult for natural microbial organisms to break them down. This leads to their persistence in the environment and contributes to the global plastic waste crisis.

To mitigate the environmental impact of non-biodegradable polymers, it is crucial to explore alternative materials and promote recycling initiatives. Governments, industries, and individuals should work together to reduce plastic consumption, promote sustainable practices, and develop innovative solutions for a greener future.

Efforts to make biodegradable polymers

With the increasing concern over environmental pollution caused by non-biodegradable polymers, scientists and researchers have been working tirelessly to develop biodegradable alternatives. These efforts aim to reduce the environmental impact of plastic waste and promote a more sustainable future. In recent years, significant progress has been made in the development of synthetic biodegradable polymers and bioplastics derived from renewable sources.

Synthetic biodegradable polymers

Synthetic biodegradable polymers are created through chemical processes that allow them to break down naturally over time. One example is polylactic acid (PLA), which is derived from renewable sources such as corn starch or sugarcane. PLA has gained popularity in various industries due to its ability to biodegrade under specific conditions, making it an attractive alternative to traditional plastics.

Another synthetic biodegradable polymer is polyhydroxyalkanoates (PHA), which is produced by certain bacteria under specific conditions. PHA is known for its biodegradability and versatility, as it can be used in various applications, including packaging materials, disposable cutlery, and even medical implants.

Bioplastics from renewable sources

In addition to synthetic biodegradable polymers, researchers have also focused on developing bioplastics from renewable sources. These bioplastics are derived from plant-based materials such as corn, sugarcane, or even algae. One prominent example is polylactic acid (PLA), which can be produced from corn starch. PLA-based bioplastics have gained popularity in packaging and food service industries due to their biodegradability and lower carbon footprint.

Furthermore, researchers are exploring the use of algae-based bioplastics, which have the potential to be more sustainable and efficient in terms of production. Algae are highly abundant and can be grown using minimal resources, making them an attractive option for bioplastic production.

Efforts to make biodegradable polymers are not only limited to synthetic and plant-based alternatives. Scientists are also investigating the use of certain enzymes and microorganisms to break down non-biodegradable plastics. By harnessing the power of nature, these innovative approaches may offer solutions to the plastic waste problem.

It is worth noting that while biodegradable polymers offer a more sustainable alternative to traditional plastics, proper disposal and recycling methods are still crucial. Biodegradability alone is not enough to solve the plastic pollution crisis. It is essential to promote responsible waste management practices and encourage the adoption of biodegradable alternatives in various industries.

Ways to manage non-biodegradable polymer waste

Polymers are commonly used in various industries due to their durability and versatility. However, their non-biodegradable nature poses a significant challenge in terms of waste management. Here are some effective ways to manage non-biodegradable polymer waste:


Recycling is one of the most widely adopted methods for managing non-biodegradable polymer waste. By collecting and processing used polymers, they can be transformed into new products, reducing the demand for raw materials and minimizing waste. Plastic bottles, packaging materials, and other polymer products can be recycled into new items such as furniture, clothing, or even building materials. Recycling not only helps reduce the environmental impact of polymers but also conserves energy and reduces greenhouse gas emissions.

Energy recovery

If recycling is not possible, energy recovery is an alternative method to manage non-biodegradable polymer waste. Energy recovery involves converting waste polymers into energy through processes like incineration or pyrolysis. These methods allow the release of energy that can be harnessed for electricity generation or other forms of energy production. While incineration may raise concerns about air pollution, advanced technologies have been developed to minimize emissions and maximize energy efficiency.

Biodegradation technologies

Advancements in biotechnology have led to the development of biodegradation technologies that can break down non-biodegradable polymers. These technologies utilize enzymes or microorganisms that can digest polymers into simpler, biodegradable compounds. While still being researched and refined, biodegradation technologies show promising potential in managing non-biodegradable polymer waste. They offer a more environmentally friendly alternative to traditional disposal methods, reducing the accumulation of polymer waste in landfills and oceans.


While conventional polymers like polyethylene and polypropylene are incredibly durable and offer unique functionality, their non-biodegradable nature creates massive waste management issues. Developing biodegradable polymers using renewable feedstocks or engineering microbes that can break down plastics could help tackle plastic pollution. In the meantime, improving recycling programs and waste disposal methods is key to reducing the environmental impacts of non-biodegradable polymers.

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