Are biopolymers a green choice?

Are biopolymers a green choice? JC thinks not.
Biopolymers, as discussed before on the pages of Engineering Materials, are a bit of a confusing topic. Everyone from the engineers looking to specify them to the general public that will consume them, feels a bit baffled about what they actually are and what they offer. For plastics, using the word ‘bio’ is akin to those in the electronics industry adding ‘i’ in front of the name. It can be... misleading.

Indeed, biopolymers are not always bona fide ‘biopolymers’. For engineering applications, it is common that a ‘bio’ option will be a mix of oil derived polymer and genuine biomass derived polymer. Blends vary between 20% to 80% or more, but the general view is that anything above 60% generally sees mechanical properties begin to fall away. And don’t think biopolymers and biodegradable polymers are the same thing, they’re not… though they frequently can be.

The whole market is muddled and difficult to find consensus. For engineers, it is definitive information that leads to decisions to use a particular material. Uncertainty here means most engineers will not risk putting it down as the material of choice on a drawing.

The biopolymer market is growing but this is broadly in line with the overall plastics industry, meaning they are not displacing oil derived materials in any meaningful way. The biopolymer sector represents less than 1% of overall global polymer demand. Biopolymers, and those behind them need to do better if they are to have positive environmental impact.

There is promise in all of this, however. Like 3D printing there’s a lot of interest in biopolymers. People are intrigued and want to access them. However, the reality is biopolymers are not yet ready for widespread adoption.

While more polymer suppliers are making biopolymers part of their catalogue of offerings, cynically, you might say this is about covering the materials’ potential expansion, and a bit of corporate social responsibility, and not converting the masses.

And, while it’s an attractive idea to return rubbish to be dissolved and repatriated by the Earth, Mother Nature doesn’t work at the rate humans need. The sustainability of the biomass needed to feed biopolymer production is questionable here - is it sustainable? I very much doubt it. The amount of natural resource needed to produce adequate biomass is immense. And no one wants biomass production plants leading to deforestation or eating in to food crop production in the same way biofuels did a decade ago. And if volumes are to increase more significantly, is there the sustainable, ethical and available biomass feedstock available? Many think not, especially if the plan is to use it once and then bin it.

Recycling and recovery of plastic materials is, for me, where progress is being made beyond what might be good PR and marketing. It gets around a few of the problems and difficulties of biopolymers, in that it reduces environmental burden and exposure to volatile oil prices. It also doesn’t have the burden of biomass production.

Environmental issues are only going to grow in importance and most experts agree tough new environmental regulations around plastics are on the horizon. Combined with a changing consumer view, the biopolymer market could well increase in coming years. But to address the volume question – and questions around the required biomass feedstock – expect the recycling of plastics to be the greener choice for the immediate future, and for some time yet.


Justin Cunningham

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Biodegradable polymers clash with product shelf live. In the world of cosmetics, they struggle with acidic environments and can erode the packaging quickly. This is a complication in the product filling stages.

HDPE and PET plastic have natural barriers that help protect the product. However, the dilemma is that these plastics need to be put back into the recycling chain by the consumer. This doesn't happen all the time and can cause environmental problems. Especially when these plastic types take years to degrade.

At the moment manufacturers are using BIOPOLYMER alternatives. Ethonal can be extracted from plant waste products like sugarcane. This can be used to construct HDPE and PET plastics.

This has some good benefits for the environment as it lowers our carbon footprint. The problem is still the biodegradable factor. It still takes years to decompose.

Plastic manufacturers and distributors like Raepak are working hard to develop a solution.

Comment David Irvine, 29/09/2017

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