Suggesting that plastics can be sustainable materials might seem contentious. Many plastics are derived from fossil fuels which are finite resources and are therefore seen as unsustainable. However, there are other ways fossil-fuel based materials can contribute to a sustainable environment, and plastics can be generated from other more sustainable feedstocks.
Many of the sustainable aspects of plastics products are derived from their durability and recyclability, topics which are explored in other cases in this exhibition. However, one property that enables them to have a positive environmental impact, but one that is often over looked, is that they are lightweight. In terms of packaging (1-4), by being light in weight, plastics products take up less space and require less fuel than heavier materials like glass, for example, in transportation. Plastics packaging also helps to reduce losses and damaged contents, therefore preventing food waste. The relative lightness in weight, when used in car parts (5), saves, on average over the lifetime of the standard car, 3000 litres of fuel.
Despite plastics using only 4% of the world’s oil production, with the rest being used for energy, transport, and heat, manufacturers have for some time been experimenting with alternative, plant-based, feedstocks. Plant materials including cornstarch (6), needles from pine trees (7), algae (8), bamboo (9), and wood (10) are harvestable, with some growing very quickly, therefore they provide a more sustainable raw material with an almost limitless supply.
Plant-based materials, also known as bioplastics, need to be considered in the wider production context of water, chemical and land use all of which have an environmental impact. The end of their life requires careful consideration too. Products made of bioplastics are not always biodegradable, if they are compostable they often need industrial conditions. If they do degrade within a recycling system they can undermine and weaken the resulting recyclate, and in landfill they can produce methane, a greenhouse gas, as they breakdown.