New wood-plastic material offers hope for reducing pollution

A new composite material made up of natural wood and plastic has been highlighted as a possible strategy for combating plastic pollution in new research co-authored by a Keele scientist.

Low to middle-income countries such as Indonesia have a particular problem with plastic pollution. This can be linked to new developments in the country which result in plastic waste, as well as increasing amounts of plastics being accepted in these countries for sorting and processing.

To tackle this problem and stop plastics finding their way into the oceans, or needing to be incinerated, scientists are looking for ways to combine plastics with natural materials to make new composites.

This research, published in PLOS One and co-authored by Keele’s Dr Deirdre McKay, was led by Dr Arif Nuryawan and colleagues from the University of Sumatera Utara (USU) in Indonesia. It involved combining low density polyethylene (LDPE) plastics with natural, Sumateran durian wood to create a new wood-plastic composite (WPC).

The WPC was created at different ratios of wood to plastic, which were all evaluated to Japanese Industrial Standards and found to pass the tests in each case, making them suitable to be used as a building material.

The research team also studied how effectively the materials were broken down by termites, to judge how well the WPC could be broken down by natural means. They found that the termites did attack the WPC materials, and although the loss of mass was comparably small, the materials did lose some of their weight. There is thus evidence that these materials can be decomposed naturally.

However, the team also found that the guts of the termites themselves contained small amounts of plastics after they had consumed the WPC materials. It therefore isn’t clear what happens to the plastics after the termites have eaten them.

The wood-plastic composite solution could also pose a further ecological problem. It’s yet to be determined if the termites host bacteria that are digesting the plastics or if they are excreting microplastics into the environment. Further research is needed to investigate the viability of such composite materials for tackling plastic pollution.

Dr McKay said: “Wood-plastic composites, comparatively inexpensive and durable building materials, can potentially divert waste plastics from the environment. But these materials also need to be assessed in terms of their breakdown products in the specific local environments where they’ll be used.”