Bioplastics for Electronic Equipment

Tackling the development of biomass-based plastics -(Bioplastics) for electronic equipment-

Bioplastics combining shape memory and recyclability

Since polylactic acid is still an expensive material, its widespread adoption will remain limited, despite its superior environmental performance. One way to try and overcome this limitation is to try to enhance its value as a material, by endowing it with new properties not available in conventional materials. With this objective, we succeeded in developing a polylactic acid that combines shape memory and recyclability, two characteristics that cannot be achieved with conventional petroleum-based plastics.

Shape memory plastics are plastics with the following ability: If they are deformed using heat and external force, then cooled and hardened, when they are heated again they return to their original shape. Generally, this characteristic is seen in plastics having a cross-linked structure (mesh structure). Unfortunately though, due to their cross-linked structure, such plastics do not melt, even at high temperatures, so recycling them (reforming them into different shapes) is difficult.

Needing to solve this problem, we developed a technology to achieve thermo-reversible cross-linking in the structure of the polylactic acid, resulting in materials displaying a combination of shape memory and recyclability. Thanks to this cross-linked structure, the material can be deformed and restored to its original shape by heating at the temperature of a hairdryer (approx. 60属C), but if heated to a typical molding temperature (160属C) the cross-linked structure dissociates, causing the material to melt, thereby enabling easy recyclability. (See Fig. 6.)

This recyclable, shape memory bioplastic allows users to freely deform the material into any shape they like, making possible all kinds of new products and applications, like futuristic wearable electronic equipment for example. (See Fig. 7.)

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