Breakthrough catalyst bids to heighten PLA performance

By Rory Harrington

- Last updated on GMT

Related tags: Polylactic acid, Pla

The production of bioplastic polylactic acid (PLA) with improved properties could soon be possible thanks to a technique under development that allows for manipulation of the material’s structure during the manufacturing process.

Research teams in from the University of Bath, in the UK, and Israel’s Tel Aviv University are developing a catalyst that they claim enhances the characteristics of PLA in terms of barrier properties as well as heat and impact resistance.

The scientists say this could allow the material to be used far more widely in such areas as microwaveable trays and hot drink cups in food packaging, as well as in engineering plastics for the automotive industry.

Greater market penetration would likely lead to increased demand and a lowering of prices as economies of scale kick in, Professor Matthew Davidson, Whorrod Professor of Sustainable Chemical Technologies at the University of Bath, told FoodProductionDaily.com.

PLA is a type of biodegradable plastic that can be made from renewable plant sources such as corn, wheat or sugar. While its use in food packaging is increasing, major challenges include the perceived limitations of its physical properties and processability.

Stereoselective

The research centres on the development of stereoselective catalysts that would allow the manufacturing of PLA to be controlled at a molecular level. The bioplastic can be made up of two types of building blocks that are mirror-images of each other – so-called left-handed and right-handed monomers, said Prof Davidson.

When the plastic is made with both types present using current technology they are jumbled together within the structure of the plastic, he added.

“Using the current technology, when the plastic is made with both types present they are jumbled together within the structure of the plastic,”​ he said. “This new project will develop a selective catalyst that will build up a polymer of ‘left-handed’ and ‘right-handed’ building blocks in a structured order so that we can control the physical properties of the resulting plastic.”

While stereoselective catalysts are not new, the team has made a breakthrough in creating robust catalysts that function under industrial conditions – something that had not previously been achieved.

“If you can control the microstructure you can make PLA with specific properties for specific functions,”​ he said.

Performance boost

Stronger PLA with greater heat resistance, higher glass transition temperatures and improved barrier properties are all potential benefits claimed for the enhanced plastic.

“The stereocomplex plastic we produce has a melting point of 240C – whereas that for conventional PLA plastic (PLLA) is around 180C,”​ said Prof Davidson as an example. “We believe this to be a significant increase.”

In the longer term, the group could also seek to develop smart packaging that can interact with food, he said

The team has already formed initial commercial partnerships aimed at scaling up production of its PLA but remains open to further approaches as the flexibility offered by the catalysts means the material could be adapted to a number of uses across different sectors.

Related topics: Processing & Packaging

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