Plant-and-wood-based material is strong, yet dissolves when discarded
While reusing cutlery is always better than discarding it, most people aren't going to be packing a knife and fork whenever they grab some fast food. With that fact in mind, scientists have designed a recyclable plant-and-wood-based material that dissolves once broken apart.
Led by Prof. Scott Phillips, a team at Idaho's Boise State University started out with a substance known as isomalt.
Derived from sugar beets, it's a granular sugar alcohol that is widely used as a substitute for conventional refined sugar. Isomalt is also utilized by bakers to create decorative structures on desserts – those structures are rigid but brittle, and quickly dissolve in water.
In an effort to boost the strength of the material, the scientists first heated isomalt to a liquid state, then added either pure plant-derived cellulose, a mix of cellulose and sawdust, or a flour made of powdered wood. Utilizing conventional plastics manufacturing equipment, all three of the mixtures were subsequently extruded into pellets which were then heated and molded into objects such as saucers, a chess piece and a dodecahedron.
In all three cases, the additives doubled the strength of the isomalt, making it stronger than plastics like polyethylene terephthalate (PET) and polyvinyl chloride (PVC). That said, the objects were still relatively lightweight, and dissolved within minutes of being placed in water.
Given the fact that some people might not want the material to dissolve so readily, the researchers proceeded to coat some of the saucers with a layer of food-grade shellac and cellulose acetate.
Those coated saucers withstood being immersed in water for up to seven days, yet they still dissolved quickly once they were broken up to expose the isomalt mixtures to the water. Importantly, the liquified material could then be reclaimed and molded into new objects which were just as strong as the originals.
The scientists now hope that the technology could be used to produce food-service items that get crushed and sprayed with water once discarded. Even if such items made it into the landfill intact, the formation of even the slightest crack would still ultimately cause them to dissolve.
A paper on the research was recently published in the journal ACS Sustainable Chemistry & Engineering. There's more information in the following video.
Source: American Chemical Society