Lignin-based UV stabilizer for renewable bioplastics

Bioplastics produced from renewable resources and recycled plastics have great potential as a material for household products and consumer goods. Plastic materials such as polycarbonate and acrylic polymer are manufactured from non-renewable fossil resources, and these materials pose toxicity threats to the user of the plastics. As an alternative, bioplastics and recycled plastics offer an attractive alternative with environmental sustainability and user safety. Cellulose acetate from wood and recycled low-density polyethylene are suitable materials for a wide variety of consumer products. A critical challenge faced by bio- and recycled plastics, however, is the resilience of plastic material against ultraviolet (UV) irradiation, which affects their durability under outdoor conditions.

This challenge can be addressed by stabilizing the plastics with chemicals and biopolymers that absorbs UV radiation, scavenge free radicals, and protects the plastics against degradation. As a renewable resource, lignin is abundantly available in Oregon as a byproduct of the lumber, pulp and paper industries. We demonstrate a method that enhances the resistance of bioplastics against UV irradiation using lignin-based phenolic UV stabilizers. Bioplastic materials containing lignin-based stabilizer are evaluated based on their mechanical and optical properties. The effectiveness of lignin-based stabilizers is validated with accelerated weathering tests, and the association between lignin chemical structure and UV-absorbing performance is revealed.