A Packaging Perspective: Why Biodegradable Packaging?

June 24, 2024|Exclusive Features, Markets, Sustainable

By Michael Laurier, CEO of Symphony Environmental Technologies Plc

Plastic made with a degradable to water (d2w) prodegradant catalyst has been tested in accredited laboratories according to ASTM D6954 or equivalent, to prove degradation, biodegradation and non-toxicity. Image courtesy of Symphony Environmental Technologies Plc.

Packaging is essential to keep our food and other goods safe from contamination and damage while in transit, and plastic is very often the best material for the job — and with the best life cycle assessments (LCA). However, plastiphobia is causing people to switch unnecessarily to other materials, which may well be worse for the environment. It might be thought that paper is more environmentally friendly than plastic, but we don’t think so.

Although plastic is very useful, conventional plastic can be a problem because it can create microplastics and lie or float around for decades if it gets into the open environment as litter. This is because the molecular weight of polymer is too high for the microbes to access it, but the problem can be solved by making the plastic product at little or no extra cost with a masterbatch of d2w (degradable to water).

Then, if the packaging escapes collection and ends up in the environment it will degrade and biodegrade (be consumed by bacteria and fungi) leaving nothing behind — just like nature’s wastes. No microplastics and no toxicity. Light and heat will accelerate the process, but it will continue even in dark, cold, conditions. Moisture is not necessary for oxidation and does not prevent it.

Some people say that they cannot be sure how long the plastic will take to biodegrade in the open environment, but it is not disputed by anyone that it will be many times faster than ordinary plastic when exposed under the same conditions in the open environment.

All this has been scientifically proven over the past 40 years, most recently in a four-year interdisciplinary study, known as the Oxomar project, sponsored by the French Government. The scientists reported that “We have obtained congruent results that clearly show that oxo-biodegradable plastics biodegrade in seawater and do so with a significantly higher efficiency than conventional plastics. The oxidation level obtained due to the d2w prodegradant catalyst was found to be of crucial importance in the degradation process.”

Products made with d2w have to be tested in accredited laboratories according to ASTM D6954 or equivalent, to prove degradation, biodegradation, and non-toxicity. Also, life-cycle assessments by Intertek have shown that oxo-biodegradable plastic has a better LCA than the other materials used for packaging.

D2w Plastic Is Not an Alternative to Waste-Management, and It Is NOT a Disposal Route

The plastic is designed to be reused, recycled, and disposed of like normal plastic, and we support governments who are improving their waste-management systems. However, the reason why there is so much concern about plastic is because so much of it still gets into the open environment, and the ONLY way to prevent plastic in the open environment from accumulating there for decades is to make it with a d2w masterbatch. It is a long stop, to protect the environment if all else fails, and should be part of the ESG planning for every responsible company.

Most of the microplastics found in the environment are caused by the fragmentation of ordinary plastic when exposed to sunlight, but these fragments are very persistent because their molecular weight is too high for microbes to consume them and can remain so for decades.

This is why oxo-biodegradable plastic was invented. It would be possible to make d2w plastic so that it started to degrade immediately, but it would then have no useful life. Sustainability must in practice be a compromise between commercial viability (i.e., cost-performance) and environmental acceptability. Bioassimilation of plastic residues in the environment is an essential but not the only requirement for packaging plastic, and in most cases, plastics require a controlled lifetime before physical degradation commences.

D2w is NOT for Landfill

If the plastic has been taken to landfill, it has been responsibly disposed of and there is no need for it to degrade. Also, if anything biodegrades in anaerobic conditions it will generate methane, which is undesirable unless the landfill has been designed to collect the gas, which most of them have not.

We can also make much-film for farmers so that it will biodegrade and be a source of carbon for next year’s crops, instead of having to be expensively removed and disposed of.

Some people have been persuaded to switch to a type of plastic marketed as “compostable” but it is tested according to EN13432 or ASTM D6400 to biodegrade in the special conditions found in an industrial composting facility. It does not therefore address the problem of plastic pollution in the open environment. Also, even in a composting facility it turns into CO₂ gas, not into compost or anything of value for the soil. It is not necessary for food-waste collection, and it seems to us that people would be LESS likely to send their food-waste for processing if they had to buy an expensive plastic bag for it. On 14th November 2022 the UK Environment Minister said: “our call for evidence suggests these materials are often stripped out at the start of the process and landfilled or incinerated.”