What are Oxo-Biodegradable Plastics?

There is growing concern about the accumulation of single-use plastic bags in landfills and oceans, which has prompted the development of alternative plastic materials that degrade more quickly and have less impact on the environment. One such alternative is oxo-biodegradable plastic, which is designed to biodegrade faster in the presence of oxygen, transforming into the harmless, biodegradable matter within a few months to a few years.

The Science Behind Oxo-Biodegradable Plastics

Oxo-biodegradable plastic is primarily made from petroleum-based raw materials, with the addition of a small number of metal salts. These metal salts facilitate the breakdown of the plastic’s molecular structure when exposed to heat and oxygen. This makes it easier for microorganisms to process the plastic, significantly shortening the degradation time from centuries to months or a couple of years. The result of the degradation process is the complete transformation of the plastic into carbon dioxide, water, and biomass.

Unlike other forms of biodegradable plastics, oxo-biodegradable plastics do not require a biological process to degrade. While microorganisms can accelerate the degradation process, oxo-biodegradable plastics can start degrading as soon as they are exposed to the open environment. The degradation time varies depending on factors such as exposure to sunlight, heat, and microorganisms. If used correctly, oxo-biodegradable plastic can last for many years, but once it becomes litter, it degrades within 12 months. In landfills, the degradation of oxo-biodegradable plastic can be accelerated if oxygen is present. However, unlike other plastics, oxo-biodegradable ones do not release methane during degradation.

Oxo-Biodegradable vs Compostable Plastics

While both oxo-biodegradable and compostable plastics are designed to biodegrade, there are key differences between the two. Oxo-biodegradable plastics are not plastics in themselves but instead, modify the molecular structure of standard polyethene (PE) and polypropylene (PP) to make them biodegradable. Compostable plastics, on the other hand, are standalone plastics that can be blended with other compostable plastics.

Oxo-biodegradable plastics are often marketed as a solution to littered plastics, providing an alternative for scenarios where plastics end up in the environment. Compostable plastics, on the other hand, are positioned as an alternative to recycling, offering an industrial end-of-life solution for managing plastic waste.

In terms of waste management, both oxo-biodegradable and compostable plastics face challenges. Neither is sorted, collected, or processed separately, and both have the potential to end up being burned like ordinary plastic. Oxo-biodegradable plastics can be recycled with regular PE or PP waste streams, but plastic recyclers often add stabilizers to ensure the quality of recycled plastic for long-term applications. Compostable plastics can be recycled on their own or chemically recycled with other plastics, although recycling PLA alone can be challenging.

In terms of end-of-life, oxo-biodegradable plastics degrade in the open environment, while compostable plastics require a controlled composting facility for degradation to occur. The time frame for biodegradation also differs, with compostable plastics degrading within two to six months in an industrial composting setting, while oxo-biodegradable plastics take one to three years to degrade in the open environment.

The Benefits of Oxo-Degradable Plastics

Oxo-degradable plastics offer several advantages over conventional plastics and other biodegradable alternatives. These include:

Retention of Properties and Strength

Oxo-degradable plastics maintain the same properties and strength as conventional plastics during their useful product life. This ensures that they can be used for a wide range of applications without compromising functionality.

Long Usability Timespan

Oxo-biodegradable plastic has a long usability period and can last for many years if stored indoors. This makes it a reliable and durable option for various industries and applications.

Reusability and Recyclability

Oxo-biodegradable plastics are reusable and recyclable, providing opportunities for multiple uses and reducing waste. This makes them a more sustainable choice compared to single-use plastics.

Methane-Free Degradation

Unlike other plastics, oxo-biodegradable plastics do not release methane during the degradation process. Methane is a potent greenhouse gas that contributes to climate change, so the absence of methane emissions from oxo-biodegradable plastics is a significant environmental benefit.

Conservation of Petroleum Supplies

Biodegradable plastics, including oxo-biodegradable plastics, help conserve petroleum supplies by reducing the reliance on fossil fuel-based materials. This contributes to the overall sustainability of the plastic industry.

Applications of Oxo-Degradable Plastics

Oxo-biodegradable plastics find applications in various industries and products, ranging from short-life products like bread wrappers to durable shopping bags. The conditions under which these plastics are disposed of can also vary, from cold and wet environments to hot and dry desert conditions. The suitability of oxo-biodegradable plastics for specific applications and conditions depends on the organizations producing or utilizing the products, which must assess the test results and market them accordingly.

Current Update

The oxo-biodegradable plastic industry continues to evolve, with ongoing research and developments. Recent updates include:

• A descriptive study of the oxo-biodegradable plastic business vertical, providing valuable insights into the global market for oxo-biodegradable bags, including applications in food and beverage, pharmaceutical packaging, agriculture, composting, and textiles.
• Expert opinions on important issues impacting the bioplastics industry, such as the problem of plastic waste escaping into the environment and the measures taken by governments to address this issue.
• Market size projections for the oxo-biodegradable plastic packaging market, indicate potential growth and opportunities in the coming years.
• The exploration of innovative solutions to address plastic waste in marine environments, including the integration of catalysts to promote the oxidation and biodegradation of polyethene by naturally occurring microorganisms.

Conclusion

Oxo-biodegradable plastics have emerged as a potential solution to the global problem of plastic waste, particularly in marine environments. These plastics degrade faster in the presence of oxygen, transforming into biodegradable matter within months to years. Despite their benefits, the adoption of oxo-biodegradable plastics faces challenges related to cost, technical considerations, and human resistance to change. The extent and timeframe of degradation and biodegradation in the environment are key factors in determining the environmental impact of biodegradable and oxo-biodegradable plastics. However, toxicity tests have shown that the final products resulting from the biodegradation of these plastics are safe and environmentally friendly. Oxo-biodegradable plastics have also received certifications for their safety in contact with food and compliance with regulatory requirements. As research and innovation continue, the future of oxo-biodegradable plastics holds promise for a more sustainable plastic industry and a cleaner environment.