Everyone knows what plastics are. However, when it comes to biodegradable plastics, many are still in the unknown.
In this post, we will highlight the different types of biodegradable plastics on the market.
Biodegradable plastic is a type of plastic that degrades within a specific amount of time.
Degradation could be a result of human actions or the activities of naturally occurring microorganisms such as fungi, algae, and bacteria.
Biodegradable plastics are environmentally friendly and are not expected to release carbon. Most biodegradable plastics are a combination of organic materials, such as cellulose and starch and chemical additives that degrade into biomass, carbon dioxide, mineral salts, methane, and water.
Over time, microorganisms present in the environment have the ability to degrade biodegradable plastics by entering the microbial food chain. Biodegradation is not defined in terms of raw-material basis, rather on the chemical composition of the polymers.
Hence, biodegradation of plastics is not a uniform process as disposal conditions vary from region to region. However, biodegradation of plastics can be tailored specifically under the inherent environmental stress in biological systems either naturally or by enzyme-assisted mechanisms.
The following are the five types of biodegradable plastics on the market today.
| Type | Main characteristic | Typical consideration |
|---|---|---|
| Hydro-biodegradable | Breakdown initiated by hydrolysis | Often requires specific composting/degradation conditions |
| Oxo-degradable / oxo-biodegradable | Uses pro-degradant additives | Environmental claims and degradation conditions should be verified |
| Photo-degradable | Breakdown initiated by UV exposure | Depends heavily on light exposure |
| Bio-based biodegradable | Made wholly or partly from renewable feedstocks | Bio-based does not always mean biodegradable |
| Synthetic biodegradable polymers | Chemically produced biodegradable polymers | Performance varies by polymer and application |
Hydro-biodegradable plastic is made from plant sources e.g. starch. The degradation is initiated by a process called hydrolysis. Hydro-plastics are the only bioplastics that can decompose both in water and soil.
They are temperature resistant and are usually composted in an industrial composter. In general, hydro-biodegradable plastics can’t be recycled with other polymer components of waste. Although this type of plastic degrades faster than oxo-biodegradable plastics, they would first have to be extracted from the waste stream and treated separately, which is more expensive.
This poses a challenge for recyclers as they find it difficult to physically distinguish the two types of plastics. The main benefit of hydro-biodegradable plastics is that they can be composted if collected, but experts fear this could harm plastic recycling as a whole.
Commonly perceived to be biodegradable, oxo-biodegradable plastics are conventional plastics with additives that fast track the breakdown process through exposure to sunlight and oxygen.
This type of plastic does not fully degrade because the additives’ role is simply to promote fragmentation of the materials. That is, it breaks down the materials into tiny fragments that remain in the environment.
The result is a huge quantity of microplastics rather than a biological material. The purpose of oxo-biodegradable plastics is to quicken the natural fragmentation processes by breaking down plastics into smaller particles.
The major difference between oxo-biodegradable plastic and hydro-biodegradable plastic is that the former can be made from recycled plastic while the latter cannot.
This means that oxo-biodegradable plastics can be recycled with other clean commercial polyolefin wastes, provided the necessary additives are added to obtain the desired level of degradation.
There are two types of oxo-biodegradable plastics on the market, they are:
As the name implies, photo-biodegradable plastics react to UV (ultra-violet) light for their degradation. When subjected to a different environment (other than UV light), it will not degrade. Photo-biodegradable plastics require initial oxo-degradation.
These plastics are derived from plants and can be either partly or fully biodegradable. Bioplastics will be considered biodegradable if they can degrade into carbon dioxide, biomass, and water in a specific time frame (depending on different standards).
Some bioplastics are made up of chemical compounds that are derived from microbes such as bacteria or by GMP (Genetically Modified Plants).
These plastics are derived from synthetic polymers, moldable plastic material, and are considered harmful to the environment.
Other biodegradable plastics available in the market are:
Some other biodegradable forms of plastics are made from banana peel, waste frying oil, sugar, avocado, etc. Plastic bag manufacturers are currently researching these types of plastics.
Bio-based and biodegradable do not mean the same thing. Bio-based describes where a material comes from, while biodegradable describes what happens to the material at the end of its life. A plastic can be made partly or fully from renewable biological resources without necessarily being biodegradable, while some biodegradable polymers can be produced from fossil-based feedstocks.
Compostable plastics are a specific category of biodegradable material designed to break down under defined composting conditions and within requirements set by relevant standards. In contrast, the term biodegradable by itself does not necessarily specify the environment or timeframe required for decomposition.
Not all eco-friendly plastics are the same. Discover how biodegradable, compostable, and oxo-degradable materials compare in our quick guide.
Depending on their properties and certification, biodegradable plastics may be used in applications such as packaging, carrier bags, food-service products, agricultural films and waste bags. However, the appropriate material depends on performance requirements, disposal infrastructure and the environmental conditions needed for degradation.
There is no single biodegradable plastic that is suitable for every application. The appropriate material depends on the product’s intended use, required performance, expected disposal pathway and the conditions necessary for degradation.
Businesses considering biodegradable packaging should review the material specification and supporting certification rather than relying on the word “biodegradable” alone.
Teong Chuan manufactures plastic packaging solutions for Malaysian and international businesses. Contact our team to discuss the material, size, printing and volume requirements for your packaging application.
