Plant-based plastic strong as PET, degrades into sugars in the environment
The new material gets its plastic-comparable strength from lignin, a biopolymer that makes up the hard wall of plant cells. In previous work, the EPFL team developed a method for cooking non-edible plant material like wood and bark in inexpensive chemicals, which extracts lignin and keeps it stable to produce a plastic precursor material. In the new study, the researchers used a different but related chemical to make a more versatile bioplastic.
“By using a different aldehyde – glyoxylic acid instead of formaldehyde – we could simply clip ‘sticky’ groups onto both sides of the sugar molecules, which then allows them to act as plastic building blocks,” said Lorenz Manker, first author of the study. “By using this simple technique, we are able to convert up to 25 percent of the weight of agricultural waste, or 95 percent of purified sugar, into plastic.”
The resulting bioplastic showed many of the desirable properties of conventional plastics. It can withstand temperatures of up to 100 °C (212 °F), has tensile strengths of up to 77 MPa, a stiffness of up to 2,500 MPa, and formed strong barriers to oxygen and water vapor. It’s versatile too, with the team demonstrating that it can be used to make packaging film, filaments for 3D printing, or fibers that can be spun into textiles.