FROM USED COFFEE GROUNDS TO BIODEGRADABLE PLASTIC

On the market, there are many bioplastics made from plant material instead of petroleum. Most of them are made by extracting starch from corn and converting it into a plastic known as polylactic acid.

Lately, researchers have been working on making plastics and chemicals from Cellulose, the main component that can be extracted from waste paper. One group made a transparent plastic from starch and Cellulose. In contrast, another group has reported a cellulose-based foam that is a better packing and insulation material than commonly used Styrofoam.

Engineers at Yokohama National University have used coffee grounds as a source for making Cellulose. Around ten percent of the dry weight of fields consists of Cellulose, they write in their research published in the journal Cellulose.

To extract the Cellulose from spent coffee grounds, the team used a catalyst that oxidizes and fragment the coffee beans’ cell walls. 

The resulting microscopic cellulose fibers were uniform in their structure. And they could easily be mixed in polyvinyl alcohol—a polymer used to produce biodegradable plastics—to make a composite plastic.

The results suggested that spent coffee grounds are a practical substitute for wood to make cellulose nanofibers. They could be used to make plastic composites for many products.