Question: I see that a large part of your career is in making plastics. My question is what do you think of the biodegradeable plastics being introduced at present to try and reduce the problem of plasic pollution? Do you think they are practicable and can be implemented into everday use easily?

John Grasmeder answered on 14 Jun 2023:

Biodegradable plastics may have their place but they have to be treated differently to conventional plastics. Do they really biodegrade? Most so-called biodegradable plastics (example: PLA) only biodegrade at temperatures of 60 – 70°C which is far hotter than any composter, even an industrial composter, can reach. Which means they are biodegradable in name only. At normal temperatures, they are as persistent in the environment as conventional plastics. Did you know, if a package is labelled “biodegradable” it is 3 times more likely that it will end up as litter and not be put in a bin or a composter?

If the biodegradable plastic does degrade, what chemicals does it into? Are these chemicals harmless? Often they are not, so they can be harmful to ground water, aquatic life or pollute the soil.

What we need to learn is that there is no such thing as a sustainable material, only sustainable materials systems. For example, we place a value on scrap metal, glass, cardboard, wood, and so we put systems in place to recycle them. In many parts of the world the same does not exist for plastics. This is starting to happen but not quickly enough.