Biopolymers and Compostable Polymers

Interest in biopolymers has increased significantly in recent years driven by a variety of social, legislative and economic factors but the definition of biopolymer itself still cause some confusion.

With this short tech article, Matrix Polymers aims to help its customers to acquire some useful terminology and help distinguishing between biopolymer and compostable material.

According to EN 13432 biopolymers are defined as polymers based on renewable resources or biodegradable polymers.

Polymers from renewable resources can be classified in 3 categories [1]:

1) polymer from natural material (e.g. starch, proteins, polysaccharide) directly extracted from biomass

2) polymer classically synthesised from bio-derived monomer (e.g. PLA)

3) polymer produced from genetically modified microorganism or bacteria (e.g. PHBV)

While degradation of a polymer is defined as a process that cause significant changes in the material performances without references to the cause of loss of properties, biodegradation is an defined as enzymatic degradation, thus specifying the cause of degradation.

Biodegradable materials are thus materials that can be converted only in carbon dioxide, water biomass and possibly methane under the actions of microorganisms.

According to CE n. 62/94 a material is defined as compostable if it is:

• biodegradable (break down into carbon dioxide, water and biomass and 90% of the organic materials is converted into CO₂ within 6 months) ;
• disintegrable (loss of visibility in the final compost means that when samples of the polymer are composted for 3 months with organic waste, mass of material residue must be less than 10%initial one and with dimension lower than 2mm);
• if it has low level of heavy metal;
• no negative effect on final compost and on compostability process ( no eco toxicity: the biodegradation does not produce any toxic material and the compost can support plant growth).

According to EN13432 a material is compostable if its components are individually compostable. This definition allows to analyse materials components, instead of materials themselves, reducing number of tests. 

If you are interested in learning about biopolymers and how Matrix Polymers can help you to succeed in this growing market, please speak contact Dr Sara Cammarano, Matrix Polymers Technical Manager at [email protected]

[1] Tuil R. Van, Schennink, G., Beukelaer, H. De, Heemst, J.van and Jaeger, R. (2000). Converting biobased polymers into food packagings. Proceedings of the food biopack conference, Copenhagen 27-29 August 2000, pp 28-30