Project works to enable use of PLA

A project, part-funded by the UK government, has developed a biodegradable plasticiser to enable PLA to be used in film and other flexible packaging.

The Development of Inherently Biodegradable Packaging Materials (DIBOP) project at Aston

University has built on a previous collaboration with speciality chemical manufacturer Robinson Brothers and also involves bag and film supplier Europackaging, technology company ThermoPrism, and medical giant GSK. The

DIBOP project, which has support from the government's Sustainable Technologies Initiative, has modified the flexibility of normally rigid PLA, so that the amount it can be stretched before it snaps has been increased from 5% to 320%.

The modifier is based on a block co-polymer, formed between PLA and polyethylene glycol (PEG). The modified PLA disappeared in a composter within 20-25 days.

Dr Allan Amass of Aston University said: "The important thing about these plasticisers is that they should be biodegradable because they may account for between 10-20% of the additives in the product. We have also made significant progress in terms of the catalyst systems needed to blend them with the product and how we can control the molecular structure of these additives."

The project developed a non-toxic replacement for the tin-based catalyst used in the synthesis of the PLA-PEG block co-polymer. The new potassium-based catalyst achieves efficient synthesis of the co-polymer while being safe for food industry packaging applications, said the research group.

After laboratory trials in the DIBOP project, a full-sized system for producing plastic bags was built and the additives were produced on a commercial scale.

The group said: "With further research the new packaging products could be in the shops within four to five years