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What are Oxo-Biodegradable Plastics?

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There is clear evidence that discarded single-use carrier bags are accumulating on land and in the ocean bodies. As a result, various plastic alternatives have been created, which deteriorate faster and have fewer impacts on the environment.

Oxo-biodegradable plastics are a type of plastic that biodegrade faster in the presence of oxygen, transforming into the harmless, biodegradable matter within a few months to a few years.

What are oxo-biodegradable plastics?

Oxo-biodegradable plastic is made of petroleum-based raw materials and a small number of metal salts. The metal makes it possible for the molecular structure of plastic to break down when exposed to heat and oxygen. 

The plastic will come to a state where microorganisms can process it. This shortens the degradation from centuries to months or couple of years. The plastic becomes fully degraded into carbon dioxide, water and biomass.

Oxo-biodegradable plastic is frequently referred to as “degradable” plastic because it does not require a biological process to degrade. 

Microorganisms will accelerate the degradation process. This gives oxo-biodegradation a distinct advantage over other methods for degrading plastic. The degradation time differs depending on the measure of exposure to degradation elements like sunlight, heat and microorganisms.

Oxo-biodegradable plastic degrades the second it reaches the open environment. If the plastic is used correctly, it could last many years, but once it becomes litter, it degrades within 12 months.

In a landfill, the degradation of oxo-biodegradable plastic will speed up if oxygen is accessible.

However, unlike other plastics, oxo-biodegradable ones do not release methane when they degrade.

The life cycle of oxo-degradable plastics

Degradation is initially prevented by the presence of polymer stabilisers in the plastic, which ensures a useful service life. Once the stabilisers have been exhausted, OXO-biodegradation will begin.

Biodegradation has two phases.

It starts with an “abiotic degradation” phase. The objective of this first phase is to reduce the molecular load of the polymer to enable microorganisms to process it. Microorganisms do not play a primary role in this phase.

The abiotic phase begins with oxygen (OXO refers to oxygen). OXO-biodegradation and can be accelerated by UV light or heat. 

The second phase is the biotic phase. Bacteria and other microorganisms begin eating the residues. Water is produced simultaneously, the microorganisms breath out CO2 and die to form biomass.

Oxo-biodegradable vs compostable plastics

The action of living organisms can decompose biodegradable plastics, into water, carbon dioxide, and biomass. 

Biodegradable plastics are commonly produced with renewable raw materials, microorganisms, petrochemicals or combinations of all three.

Compostable plastics are produced from renewable materials like corn, bamboo, potato, tapioca starches, cellulose, soy protein and lactic acid.

Compostable plastics are non-toxic and decompose back into carbon dioxide, water, and biomass when composted.

Following are some key difference between the two:

 

  • Nature

 

OXO-biodegradable is not plastic in itself. It’s a prompt to reduce the molecular load of standard polyethene (PE) and polypropylene (PP) to make it biodegradable.

Compostable plastics are plastics on its own, and it’s possible to blend it with other compostable plastics. For example, Poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) can be blended. 

  • Marketing Claim

OXO-biodegradable is advertised as a solution to littered plastics. Plastic should not end up in the environment, but unfortunately, plastics are not always recycled. OXO-biodegradable is an alternative solution for scenarios where plastics end up in the environment.

Compostable plastics are marketed as an essential solution, sort of an alternative to recycling. Compostable plastics provide an industrial end-of-life solution to manage plastic waste.

 

  • Waste Management in reality

 

Neither Oxo-biodegradable nor compostable plastics are sorted, collected or processed separately. Both have a high chance to end up burned, which makes it no better or worse than ordinary plastic. 

OXO-biodegradables can be recycled with regular PE or PP waste streams. Plastic recyclers can’t be sure that plastic waste is free from contaminants and will usually add stabilisers if they want to make recycled plastic for long-term applications.  

Compostable plastic is recyclable in general. It can be precisely recycled on its own or might be chemically recycled with other plastics. However, it’s challenging to recycle PLA alone. 

 

  • End-of-life

 

Both OXO-biodegradable and compostable plastics are end-of-life options for plastics. OXO-biodegradable will biodegrade in the open air in the environment.  

Compostable plastics will degrade in a controlled environment, a composting facility, where the process begins with human intervention.

 

  • Residue

 

OXO-bio and compostable plastics both claim that the biodegradation cycle will transform plastic into carbon dioxide, water and biomass.

The biodegradation time period is different. Compostable plastics degrade in a time span of two to six months in industrial compost. OXO, on the other hand, will degrade in a time frame of one to three years in the open environment.

In both cases, microorganisms consume plastic and inhale out carbon dioxide. The degradation of compostable plastics releases carbon dioxide in the environment much quicker than OXO-biodegradable. OXO-biodegradable releases carbon dioxide much slower.

Eventually, the bacteria die, and the resulting biomass is the “dead bodies” of the microorganisms. Compostable plastic calls this biomass “compost”. However, OXO-bio doesn’t claim to produce compost.

Benefits of oxo-degradable plastics

Following are some advantages of using oxo-degradable plastics: 

  • Retain the same properties and strength as conventional plastics during its product life.
  • Oxo-degradable plastic has a long time span of usability. It will last many years if stored indoors.
  • Oxo-biodegradable plastic is reusable and recyclable.
  • Oxo-biodegradable plastic will degrade in a landfill, and the process does not produce methane.
  • Biodegradable plastics help conserve petroleum supplies.

Applications of oxo-degradable plastics

The applications for which oxo-biodegradable plastics are typically used can vary from very short-life products such as bread-wrappers that last a couple of months, to strong shopping bags expected to last five years or more. 

The conditions under which they are probably going to be disposed of can also vary from cold and wet conditions to hot and dry desert conditions. 

It is for the organisations producing or utilising the products to assess the test results to judge the suitability of the tested material for those applications and conditions, and to advertise them accordingly.

Current update

November 10, 2020 – A descriptive study of the oxo-biodegradable plastic business vertical with respect to primary growth stimulants, opportunities, and restraints. It provides valuable insights into the Global Oxo-Biodegradable Bags Market for the years 2020-2025. Food & beverage, pharmaceutical packaging, agriculture & composting textile are the applications included in the Oxo-Biodegradable Bags market report. 

November 9, 2020 – Michael Stephen, an international expert on bioplastics, shares his thoughts and opinion on important issues impacting the bioplastics industry. Plastic which has escaped into the open environment is causing a serious problem and the UK governments are taking measures to reduce it. Nevertheless, it is realistic to expect that despite those measures a significant amount of plastic will still get into the open environment from which it cannot be collected for recycling or anything else.

November 7, 2020 – Oxo-biodegradable Plastic Packaging Market size will reach xx million US$ by 2029, from xx million US$ in 2018, at a CAGR of xx% during the forecast period. In this study, 2018 has been considered as the base year and 2029 as the forecast period to estimate the market size for Oxo-biodegradable Plastic Packaging.

October 19, 2020 – Among the 300,000 tonnes of plastic waste found today on the surface of the oceans, more than half are made of polyethene. The biodegradation of normal polyethene (PE) by microorganisms is very slow, and a solution proposed by scientists consists of integrating a catalyst that promotes the oxidation of PE to make it more accessible for biodegradation by naturally-occurring micro-organisms.

Conclusion

Marine plastic litter is a global environmental problem since almost 10% of the 299 million tons of plastic produced worldwide gets accidentally or deliberately into the environment.

Thus, to prevent toxicity to the environment and the danger to marine lives, oxo-biodegradable plastics were introduced. 

It is a form of plastic that has elements to biodegrade significantly faster in the presence of oxygen than conventional plastics, turning into the supposedly harmless biodegradable matter over a period of a few months to a few years.

Despite that, there are three main reasons why oxo-biodegradable plastic could be a hard sell: 

  • Cost – Bio‐based plastics are more expensive than petro‐based ones. 
  • Technical Challenges – Large‐scale production of biodegradable plastics comes with a host of challenges, from low reactor space‐time yields to considerable variation in feedstock composition and structure. 
  • Human element – Not invented here (NIH) is an old yet highly relevant adage which is the tendency to avoid using or buying products from external origins.

The most pressing issues about biodegradable and oxo-degradable plastics are the extent to which they degrade and biodegrade in the environment and the timeframe in which this occurs. 

These issues are critical to determining if biodegradable and oxo-degradable plastics, and the substances they produce, are likely to accumulate and exert an impact on the environment.

The conclusion of toxicity tests is that the final products resulting from the biodegradation of plastics, and oxo-degradable plastics, do not contain any residual toxic components and are environmentally safe.

Oxo-biodegradable plastic has been certified by RAPRA Technology Analytical Laboratories as safe for long-term contact with any food type at temperatures up to 40°C according to European regulations and certified as compliant with FDA requirements in the US.

 

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