Recyclable shape-memory biopolymer
Unlike conventional petroleum-based plastics, polylactic acid (PLA) plastic is mass produced by chemical synthesis using raw materials derived from corn. The production of PLA contributes less CO2 to the atmosphere than that of conventional plastics and offers superior biodegradability after disposal. Because PLA plastics are often more expensive than conventional ones, researchers are developing ways to add value to PLA plastics.
NEC Corporation’s Dr. Masatoshi Iji has developed a PLA-based bioplastic with shape memory and recyclability. The polymer deforms with heat and external pressure and remains in that altered shape when cooled. Once reheated, the plastic returns to its original shape. Shape memory conventionally requires plastics with a cross-linked structure, which prohibits melting and thus recycling. However, NEC’s shape-memory polymer utilizes a characteristic called thermo-reversible cross-linking. The material can be deformed and restored to its original shape by heating at the temperature of a hairdryer (approx. 60 C), but if heated to a typical molding temperature (160 C) the cross-linked structure dissociates, causing the material to melt and enabling easy recyclability.
This recyclable, shape-memory bioplastic allows users to deform the material into any shape, making possible all kinds of new products and applications, like futuristic wearable electronic equipment.
Contact: NEC Corporation, Tokyo, Japan.
For more information, see Transmaterial 2: A Catalog of Materials That Redefine our Physical Environment