Making green plastics viable for everyday use

Feng Zengkun The Straits Times AsiaOne 3 Nov 14;

Scientists in Singapore might have found a way to turn throwaway plastic items from an enemy of the environment into an ally.

They have devised a technique to make renewable and biodegradable plastics called bioplastics more commercially viable.

It makes use of lignin - an organic polymer usually found in wood and plants, and traditionally a waste product of paper mills and palm oil plantations - thus killing two birds with one stone.

Project leader Nasir Al-Lagtah from Newcastle University International Singapore said the discovery could make plastics environmentally friendly.

"That would realistically help to reduce our environmental impact," said the lecturer in chemical engineering at the school.

The Singapore Environment Council found last year that the country uses three billion plastic bags a year.

Most plastics today are petroleum-based, and they are strong, low-cost, light-weight and water-proof.

Although bioplastics made from natural resources such as soy and fish protein are more environmentally friendly, their use has been limited because they are not strong enough and tend to absorb water.

Dr Al-Lagtah's laboratory tests showed that lignin reduces water absorption in soy protein-based plastics by up to nearly 80 per cent. It also more than doubles the material's tensile strength - the amount of force the material can resist before splitting apart.

Other researchers have found that lignin likewise improves plastics made with fish protein.

Dr Al-Lagtah said one challenge is how to extract the lignin, as it exists in many forms in various biomass materials.

He is now studying whether bio-waste with a high lignin content can be used directly in the bioplastics, which would do away with the need for extraction. He said several firms that produce large amounts of agricultural waste have expressed interest in the process, but declined to name them because of ongoing talks.

He has produced small amounts of the improved bioplastics, but the immediate goal is a more commercially viable prototype. He expects it to take about a year to 18 months after more researchers come on board.