What raw materials are bioplastics made of?
We all know that conventional plastics are made from fossil fuels. On the other hand, bioplastics are characterized as being bio-based, bio-degradable, or both. Once left in a natural environment, they biodegrade back into biomass that blends harmlessly with the soil. But what are the raw materials used in the production of bioplastics?
Most commonly, the raw materials for bioplastics are plants rich in carbohydrates, frequently called biomass. We recognize three main generations:
The first-generation feedstock is directly produced from food crops, it refers to plants that serve as food for both humans and animals. Their main benefits are that they can offer high yields on a low amount of land. The prime examples are plants like corn, sugarcane, sugarbeet, cassava, wheat, potato, rice, and plant-based oils.
The main criticism of the first generation is that it diverts human and animal food for other uses and therefore threatens the food chain.
The second-generation feedstock is based on plants which is not suitable for human or animal consumption. It can either be non-food plants or even waste materials produced from the first-generation feedstock. The most used plants are wood (cellulose) and different grasses. The most common waste products are waste plant oils.
In order to not interfere with the food chain, the second generation crops should be grown on non-agricultural land, also known as marginal land.
After some research into the effectiveness of algae uses in bioplastic production, they were separated from the second generation, and they have been redefined as the third-generation feedstock.
They display the highest yields and affectiveness for bioplastic production with the lowest raw materials inputs. Those do not compete with land use for food crops, and they do not require fertilizers, pesticides, or other products. Moreover, the resulting bioplastic biodegrades in around 12 weeks in soil and much faster in water.
Apart from the three generations, there are smaller amounts of bioplastics produced from other raw materials. For example, casein plastic actually has a long history as it was one of the first plastics produced, it is based on the protein naturally occurring in cows´ milk called casein. Moreover, scientists around the globe investigate the possibilities of newer and improved methods of bioplastic production.