(750a) Lignin-Based Performance Chemicals for Plastic Materials

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. One of the critical challenges faced by bio- and recycled plastics, however, is the modest strength of the material. Without the use of a UV stabilizer, the strength of plastic material decreases under outdoor conditions due to damages incurred by UV irradiation.

This challenge can be addressed by fortifying and 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 U.S. 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. Plastic materials containing lignin-based stabilizer are evaluated based on their mechanical and optical properties. The effectiveness of lignin-based stabilizers is tested through accelerated weathering, and the association between lignin functionalities and UV-absorbing performance is investigated. Detailed characterization of the UV-induced structural changes in plastic material has highlighted the effect of lignin-based additives on material performance.