Akira Iwamoto

Enzymatic degradation of plastics containing polycaprolactone

Abstract Plastics composed of polycaprolactone (PCL) and conventional plastics (polyethylene, LDPE; polypropylene, PP; nylon 6, NY; polystyrene, PS; polyethylene terephthalate, PET; and poly-β-hydroxybutyrate, PHB) were prepared by mechanical blending. PCL degradability of blends of PCL and PS, PCL and PET, PCL and PHB by Rhizopus arrhizus lipase dropped off remarkably. In contrast, the blends of PCL and LDPE or PP retained high biodegradability of PCL. In the case of blends of PCL and NY or PS, the biodegradability of PCL did not change so much. In addition, it was found that the degradabilities of PCL-LDPE blends by the lipase would be controlled by combining the melt viscosity of PCL with that of LDPE. In general, it seems that the higher the miscibility of PCL and conventional plastics, the harder the degradation of PCL on their blends by the lipase.