The World of Bioplastics

  • The use of bioplastics is steadily increasing in many countries, especially in Europe
  • Bioplastics can be non-biodegradable
  • ASTM D6866 measures the exact percentage in bioplastics that came from renewable sources

bioplastics for ASTM Method D6866 testing
Bioplastics may not have the exact properties of their fossil fuel-based counterparts and their production is not easy, but their use in the market has been steadily increasing, especially in Europe.

Bioplastics or “organic plastics” are commonly used as packaging materials, disposable catering products, compostable waste bags, and biodegradable mulch films. Reabsorbing organic plastics are also used in the medical sector. Bioplastics are water vapor permeable but they are waterproof, hence they make good materials for sanitary products. Consumer electronics, leisure goods, and even the automobile industry are starting to use bioplastics due to their low electrostatic charging properties.

ASTM D6866 for Bioplastics

The exact percentage in bioplastics that came from renewable sources (e.g. plant derivatives) can be known via ASTM D6866 – an industrial application of radiocarbon dating. ASTM D6866 measures the Carbon 14 content of biobased materials; and since fossil-based materials no longer have Carbon 14, ASTM D6866 can effectively dispel inaccurate claims of biobased content.

Examples of ASTM D6866 results:

Product A – plastic bag manufactured from petroleum-derived polyethylene

Product A biobased content = 0%

Product B – plastic bag manufactured from biomass-derived polyethylene

Product B biobased content = 100%

Bioplastics vs Petroleum-based Plastics

According to European Bioplastics, direct comparison of petroleum-based plastics with bioplastics may lead to an inappropriate image because the former are now commodities while the latter are still in early stages of development.

But are bioplastics truly more environmentally and economically advantageous than fossil fuel-based ones? Although several life cycle assessment studies have documented that bioplastic production consumes less fossil energy and have less carbon dioxide emissions, these findings would still not support that “bioplastics are the more environmentally friendly solutions.”

In terms of economics, bioplastics production in Europe can help reduce dependence on imports and may create jobs and export opportunities.

What are Bioplastics?

According to European Bioplastics, there are two underlying concepts that determine whether a “plastic” is a bioplastic or not – compostability and raw materials.

Bioplastics are (1) certified compostable plastics that are based on renewable and/or fossil resources, or (2) those that are made from renewable sources.

For plastics to be considered compostable, they must be certified according to the legally binding standards EN 13432 or EN 14995 in Europe, ASTM D-6400 in the US, or ISO 17088 in other countries. In Europe, products made of compostable plastics usually carry the trademarked “seedling” logo.

Plastics made from renewable resources such as sugar, starch, vegetable oils, or cellulose are bioplastics. Most of the ones available in the market nowadays use corn, potatoes, cereals, sugar cane, and wood as feedstocks.

Are Bioplastics Biodegradable?

NOT all bioplastics/biopolymers are biodegradable. The degree of a material’s biodegradability depends on its molecular structure and not on its source.

The terms biobased and biodegradability may be related, but they are not synonymous nor are they interchangeable. If a material is biobased, it comes from plants or animals, but it does not necessarily follow that it is biodegradable. A material is biodegradable only if microbes in the environment can break it down and use it as a food source.

Some forms of cellulose are, in fact, non-biodegradable while some that are derived from petroleum do biodegrade contrary to popular opinion. Nowadays there are synthetic plastic resins that will biodegrade and compost just like paper. There are also bioplastic materials, such as Braskem’s bio-polyethylene, that do not biodegrade.

Bioplastics vs Biofuels vs Food

The European Bioplastics claims that bioplastics have no impact on food supply or availability and should not be regarded as a threat to sustainable development. Unlike biofuels, bioplastic volumes are relatively low and the cultivation area needed to supply the bioplastics industry is very small.

Moreover, the bioplastics industry is making a strong effort to use agricultural residues (cellulosics), other waste streams, and feedstocks that do not compete with food markets. There are bioplastic materials in production that use non-edible, non-food wastes like potato skins.