What are bioplastics made of?

Plastics are all around us. Virtually every manufactured item either has plastic components or had plastics involved at some time during its construction.  Around 99.8% of the time, those plastics were made from fossil fuel sources. But that tiny remainder – 0.2% – represents plastic made from biological sources, including seaweed, plants and agricultural byproducts. These are the bioplastics, and their tiny share of global plastic production is growing every year.

At Roocreate, we’re excited about the capabilities of bioplastics.

The reason is that, to date, most of the bad press about plastics stems from the fact they are made with fossil fuels and don’t biodegrade easily. Bioplastics from renewable living sources however give all the convenience of conventional plastic without much of the pollution. And scientific advances are making them greener and more economically viable every year.

Seaweed bioplastics

While other feedstocks compete with crops for field space on Earth’s limited arable land and freshwater, seaweed comes from the vastness of the oceans. Requiring no irrigation and having the fastest growth rate of any plant (sometimes faster than the hour hand on a clock), seaweeds are an ideal candidate for bioplastics.

Specifically, these giant algaes suits use in polylactic acid bioplastics (PLA). It is a material that holds a great deal of promise to be the world’s leading kind of bioplastic.

While there are over 20,000 types of seaweed and kelp forests that rival the Amazon, the global annual harvest is very small. Further, this field is very new and only a few kinds are currently used for bioplastics.

These are not usually harvested from wild “sea forests”. Instead, they are cultivated intentionally, either close to shore or alongside fish farms and are naturally fertilised by fish waste (especially the nitrogen and phosphorus that is otherwise washed away). When the time is right the seaweed is harvested, brought ashore, dried, milled and treated to extract the lactic acid needed to create PLA.

Cassava starch bioplastics

This is what we use here at RooCreate! Cassava is a tropical food crop. Its various names, such as manioc and tapioca, all refer to the roots of vigorous, drought-tolerant shrubs in the euphorbia plant family. As harvested, cassava is at once poisonous and almost pure starch. After lengthy treatment for safe human consumption, it provides a lot of energy but otherwise lacks nutritional value. For these reasons, it is an ideal feedstock for starch-based bioplastics.

The factors that make cassava so promising for bioplastics (and biofuels) are interlocking:

  • It grows well in impoverished or dry soils that are marginal for other crops
  • Take out its water weight and cassava is 95% starch
  • It is poisonous and requires lengthy and costly preparation to make it safe for human consumption.

Yes, despite cassava being vital for food security for millions of people around the world, it is toxic (sometimes lethally). After harvest, the roots require thorough washing, peeling, preparation and cooking before they can be eaten. This can take days. For industrial uses, neutralising these natural poisons is not important – greatly increasing the economic case for cassava starch’s use in bioplastics.

The crop shows great promise given that thermoplastics derived from various sources of plant starch currently dominate bioplastics around the world – accounting for about half of global annual production.

Can plastics actually be green?

Bioplastics is a rapidly developing field. Scientists around the world are using advanced chemistry to make regular breakthroughs in developing new materials, reducing ecological impacts and making growing the feedstocks more profitable for producers.

At the same time, sources for these new bioplastics are being developed to fit in with existing sustainable agriculture and aquaculture practices, often through using waste or byproducts. Making plastics green is the goal.

As the field continues to enlarge its current 0.2% share of the world plastics industry, you will see bioplastics around you more and more.

Bioplastic facts

  • They are certainly better for the environment overall, but not all kinds of bioplastic biodegrade. Some rarer kinds are even more stable than traditional plastics.
  • Most bioplastics are derived from some kind of saccharide or “sugar”, such as cellulose, glucose or lactose.
  • While the field is developing rapidly, bioplastics are nothing new. Both cellophane and celluloid are bioplastics and have been around for more than 100 years.