Are we really being our best bioplastic?

Photo by Layne Harris on Unsplash

There are three types of bioplastic in the world.

Those natural biopolymers that nature already creates, like wool for keeping sheep/us warm.

The second category is where we look at petrochemicals and think ‘Hey – nothing wrong with that at all! Let’s do exactly that from biomass (like plant material or wood), same molecular formula, same benefits’ (and yup, same problems). This includes the world’s most widely used manufactured plastic, polyethylene, but making it from sugarcane instead of crude oil.

Then there is number 3. The ‘let’s take something from nature, and then make it behave in a similar way to petrochemicals, because that’s what we want and what we are used to.’ Polylactic acid is a good example, you know, the one used to make beer cups that say ‘this is not a plastic cup’ (this is a plastic cup).

So far, so year 2000.

But in the last two cases we are trying to bend biomass to behave more like crude oil, and you have to ask yourself - why? Why would you want to create bioplastics that cannot biodegrade for centuries, when disposing of plastic waste is one of the critical problems of our times? Biomass offers a phenomenal opportunity precisely because it doesn’t behave like crude oil. Biomass is a great source of functionality, which allows us to do so many more things than we do with conventional plastics.

1. Functionality. We can build in compostability. What does this mean in practice? Well, you could pop it in the food waste, where it will be converted into renewable energy, or into the home compost, where it will break down into water, carbon dioxide and biomass. If it does find its way into the ocean, then it can also break down fully in the sea, not hurting marine life or creating micro-plastics. Remember only 9% of conventional plastic gets recycled, 34% ends up in the marine and soil environment, where it does not degrade for hundreds of years.

2. Most novel bioplastics will not stand up to being recycled. The dirty secret is that nothing can be recycled indefinitely – most plastics can only be recycled a couple of times into lower quality materials, before they are destined for landfill.  But functional biopolymers give us the ability to upcycle rather than recycle. This is where we can selectively degrade them back down into their individual building blocks to be rebuilt again. Doesn’t matter what else is with them, so no more sorting your plastics (yay!) This was always the dream of recycling – but hey, again, conventional plastics don’t have the functionality, yes, looking at you polypropylene. 

3. But, the most exciting developments that are coming thick and fast in this space is that we can actually build on all this amazing functionality and start getting biopolymers to be really smart for us.

What do I mean by smart?

Well, what about a biopolymer that changes colour to tell us when your food is on the turn, or has the ability to absorb water away from food, massively extending product life by months? Or actively attacks bacteria so they can never start growing in the first place? What about them being part of a composite concrete mix that reacts with air so that when a crack forms in a building or foundation it will grow to fill it? How about a bioplastic that can actively absorb bad smells, or how about some 3-D printing with live cells, which then consume the bioplastic matrix to grow… The list goes on. And on and on, and on.

Basically, we are going to have to move away from fossil fuel resources at some point. Rather than this being completed with a sense of horror and attempting to replicate what we already do – with most of the same problems - from biomass, this could be an opportunity to create a new world of plastics, where increased functionality gives us increased performance. A world where we can (up)recycle indefinitely, one where we fill our food-waste bins with plastic film in the knowledge that it is coming right back to us as sustainable energy tomorrow, and one where our plastics start smartly helping us with our everyday lives, rather than just dumbly littering our parks. 

This is the future that we are helping to develop at Kelpi – join us on this journey.

Professor Chris Chuck