5 Types Of Biodegradable Plastics In 2025

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What are the different types of biodegradable plastics, and are they truly better than non-biodegradable plastic? 

To start, let’s briefly see the 5 types of biodegradable plastics – 

• Bio-based plastics – produced partly or entirely with biologically sourced polymers
• Synthetic bioplastics – derived from synthetic polymers
• Oxo-degradable plastics – conventional plastics with additives to break down faster
• Photo-biodegradable plastics – react to ultra-violet light, and requires initial oxo-degradation
• Hydro-biodegradable plastics – are made from plant sources (like starch) and the degradation is initiated by hydrolysis
• + Compostable plastics – Compostable plastics are typically made from materials like starch, cellulose, proteins, or algae, which are designed to decompose under specific composting conditions

The topic of bioplastics is very tricky, so let’s take a further look at each of the types of biodegradable plastics, and are there any better than regular plastics.

Let’s begin!

5 Types Of Biodegradable Plastics (+ Compostable Plastics)

Bio-based Plastics:

What are they:

Bio-based plastics are made from renewable sources like plants, algae, or bacteria. These plastics can be entirely made from materials sourced from living organisms, or partially, in combination with synthetic polymers.

Examples of renewable carbon resources include corn, potatoes, rice, soy, sugarcane, wheat, and vegetable oil. Usually, most biobased plastic is just partially biobased. 

It is considered biodegradable if it can degrade into water, carbon dioxide, and biomass in a given time frame (dependent on different standards). (1)

Challenges: 

Challenges for bio-based plastics include the inconsistency in their renewable content and concerns about their full life cycle impact. Not all bio-based plastics are entirely renewable, raising questions about their overall eco-friendliness. 

Examples:

• Polylactic Acid (PLA)
• Polyhydroxyalkanoates (PHA)
• Bio-based polyethylene

Synthetic Bioplastics:

What are they:

Synthetic bioplastics are engineered to imitate the properties of traditional plastics. Unlike bio-based plastics derived from living organisms, synthetic bioplastics are manufactured using synthetic polymers. It differentiates from conventional plastic with its composition or degradation characteristics.

Challenges: 

Issues include sustainability concerns due to energy-intensive production, a lack of standardized definitions, and vagueness surrounding their true environmental impact. 

Examples:

• Polybutylene Succinate (PBS)
• Bio-based polyethylene terephthalate (PET)
• Specific bio-based polypropylenes

Oxo-degradable Plastics:

What are they:

Oxo-degradable plastics are often composed of conventional polyethylene (aka plastic), but feature additives. These additives facilitate quicker breakdown when exposed to oxygen and ultraviolet (UV) light, causing the plastic to fragment into smaller pieces. (1, 2)

Challenges: 

Oxo-degradable plastics, though intended to break down quickly face challenges such as microplastic issues, variable degradation effectiveness, and the lack of standardized specifications. The additives used can raise environmental concerns, too.

Examples:

• Polyethylene with oxo-additives

Photo-biodegradable Plastics:

What are they:

Photo-biodegradable plastics react to ultraviolet (UV) light, initiating a quicker breakdown process. Typically, they undergo an initial stage of oxo-degradation to make them susceptible to following biodegradation under UV light exposure. 

Challenges: 

Photo-biodegradable plastics, which respond to UV light, encounter challenges due to their restricted use in specific environments, dependence on oxo-degradation, ongoing research requirements, and potential issues in waste management systems.

Examples:

• Some formulations of polyethylene with photo-sensitive additives

Hydro-biodegradable Plastics:

What are they:

Hydro-biodegradable plastics, derived from plant sources like starch, initiate degradation through hydrolysis. This involves breaking chemical bonds through water absorption. Microorganisms, enzymes, and moisture work together to break down these plastics into simpler compounds.

Challenges: 

Hydro-biodegradable plastics, derived from plant sources, encounter challenges such as limited application in dry environments, variable decomposition rates, resource intensity in production, and dependence on specific disposal conditions for effective degradation.

Examples:

• Starch-based plastics
• Specific cellulose-based materials

There’s another material worth mentioning, and that’s it…

Compostable Plastics:

What are they:

Compostable plastics require specific composting conditions, involving aerobic (oxygen-dependent) environments. They break down into carbon dioxide, water, inorganic compounds, and biomass without leaving harmful residues. 

Proper disposal in commercial composting facilities is crucial, as these plastics won’t break down on their own in landfills, as litter, or in marine environments. (1, 2, 3) They need specific conditions, which can be generally found only at commercial composting facilities. The different criteria in different countries are:

• European Standards: Compostable plastics must break down under industrial composting conditions in less than 12 weeks. 
• Australian Standards: Compostable plastics should disintegrate within 12 weeks. Complete biodegradation within six months, converting 90% or more to CO2, water, and biomass. 
• US Standards: No more than 10% of the original dry weight should remain after 84 days. 90% of the organic carbon in the test materials must convert to carbon dioxide within 180 days.

Challenges: 

Compostable plastics, requiring specific disposal conditions, face challenges such as limited infrastructure for proper disposal, potential misuse and contamination issues, resource intensity in production, and varying degradation timeframes across regions.

Examples:

• Resins made from potato starch
• Soybean protein
• Cellulose

FAQ

Are biodegradable plastics truly biodegradable? 

Biodegradable plastics can break down naturally, but the timeframe and success depend on environmental conditions. In landfills or oceans, they may persist for hundreds of years. Typically, they are expected to decompose fully in 3 – 6 months, influenced by factors like temperature and moisture. (1)

Biodegradable Plastic Study: A 2019 study revealed that biodegradable plastic bags remained intact after three years, whether submerged in the sea or buried underground. This challenges the expected degradation timeframe. Check a quick video that summaries the study here:

Biodegradable bags can hold a full load of shopping after 3 years in the environment

How does plastic biodegrade? 

Most biodegradable plastics, derived from traditional petrochemicals, contain additives for faster breakdown under light, oxygen, moisture, and heat. Microorganisms like bacteria accelerate decay, resulting in decomposition into water, carbon dioxide, methane, and biomass. (1)

Are biobased plastics always biodegradable, while fossil-based plastics never are? 

Biobased plastics aren’t always biodegradable, and some fossil-based bioplastics are. The truth is that if a material can biodegrade does not always depend on its origin (renewable or fossil). It depends on its chemical structure and if it can be eaten by bacteria, fungi, and algae in a set environment and timeframe.

Are biodegradable plastics always compostable? 

No, as “biodegradable” and “compostable” differ. Compostability depends on specific conditions and standards, and not all compostable plastics suit all industrial or home composting facilities. 

Are compostable plastics suitable for all industrial composting operations?

It varies. Some standards demand complete biodegradation in 180 days, conflicting with industrial composters that finish in 60-90 days. Suitability depends on the compostable plastic’s composition and the composting system’s conditions. 

Are all compostable plastics suitable for home composting? 

No, as some need higher temperatures that are found in industrial facilities and not in backyard composting. The compostable plastic breakdown in your backyard depends on your composting system, its conditions, and the product’s composition. 

Can biodegradable plastics break down in landfills? 

No, most landfills limit biodegradation due to low oxygen and moisture levels. (1)

Biodegradable vs. compostable: which is better? 

Composting is generally faster, but it requires specific conditions. Home compostable alternatives may be the best choice, especially if you have a home compost.

Can you put compostable plastics in your home compost? 

Not all compostable plastics can break down in home compost. It depends on factors like heat, and labels like “home compostable” indicate suitability for home composting. Just make sure to get items certified as “home compostable”.

Summary

The disposal of biodegradable and compostable plastics poses challenges due to diverse materials, varying characteristics, and inconsistent standards. 

The market is flooded with various materials, each with its quirks, making it tricky to make the right disposal decisions. It’s not a one-size-fits-all situation, and different places might have different rules or even lack proper conditions for these products. 

So, the smart move is to check with your local recycling, compost, or solid waste operators, to make the right choice when it comes to the end-of-life of biodegradable or compostable products.

Key points to remember:

• Diverse challenges exist in biodegradable plastics disposal, and local regulations impact proper disposal methods.
• “Biodegradable” means something can be decomposed by bacteria or other living organisms. (1)
• Not all bioplastics are biodegradable (+ “bioplastic” isn’t a synonym for biodegradable). (1)
• Composting typically takes place in aerobic environments (requires oxygen), while biodegradation may take place in anaerobic environments (doesn’t require oxygen). (1) 
• Different bioplastics require different conditions for effective breakdown. Understanding each type’s unique properties is crucial for proper disposal. 
• In the end, opting for reusable, durable items is the most environmentally friendly choice.

Let me know in the comments below if you have any questions. 🙂