Article by By Dr Stephen Chapman, Aberystwyth University
As a society we are fundamentally ambivalent to plastics. On the one hand the convenience, flexibility and durability of plastics derived from fossil fuel means that they are used for most of the consumer goods we purchase every day, from packaging right up to complex engineering components. The big four oil-based, non-biodegradable plastics are polyethylene, polypropylene, polystyrene and polyethylene terephthalate. Combined with other synthetic plastics, we produce approximately 140 million tons worldwide each year, surpassing global steel production.
On the other hand, however, the durability of synthetic plastic means they are a menace to the environment. It is estimated that by 2050 there will be more plastic in the ocean than fish. Plastic does not readily degrade: the plastic toothbrush you discarded 6 years ago is still in existence. Furthermore, because of the fossil oil that goes into making them, plastics also contribute to global warming.
Fortunately biodegradable plastics offer a promising solution in our struggles with climate change, sustainability and environmental protection. The search for biodegradable plastics has been slow to start, but thanks to policies that promote a bio-based economy it is now beginning to achieve some momentum. Many plastics manufactures are now looking to go green. Bioplastics can be produced from starch- or cellulose-rich biorenewable feedstocks and are biodegradable; the use of bioplastics, polylactic acid derived from the cell walls of corn, for example, will eventually lead to a more sustainable society and help us to solve global environmental and waste management problems.
A technique to assess the environmental impacts associated with any production process, at all stages (including raw material use and indirect land use change, through to disposal or recycling of the product) is Life Cycle Analysis (LCA). LCA is used to inform various key bio-based policies and targets. As we would expect, LCA of bioplastics production estimates favorable GHG emission savings compared to crude oil derived plastic. This is especially true at end of their useful life, because bioplastics present greater recycling options and less landfill. However, the high fertiliser requirement for growing bioplastic feedstocks increases environmental impacts. Growing the feedstocks also presents a greater burden with respect to indirect land use change, especially if there is need to scale up bioplastic production. To balance these negatives, feedstock breeders are now looking at breeding feedstocks that are compositionally attractive for conversion and which exhibit less dependency on water and fertiliser, and biorefineries are looking at greener ways to convert biomass into bioplastic.
Aberystwyth University is now running an innovative distance learning module in bio-based product development, which can, combined with other interesting modules, offer you a postgraduate qualification. The module will run in September and it will give all participants an in-depth knowledge of the aims, objectives and technologies of producing commercially viable bioplastics and other products obtained from plant matter.
The above article was written by Dr Stephen Chapman, Aberystwyth University