Shigeru Yao

By Patchiya Phanthong and Shigeru Yao

Plastic recycling is one method that can reduce the amount of waste plastics in the environment. Especially in the mechanical recycling process, the waste plastics are reprocessed by mechanical approaches and reproduced as recycled products. Based on the life cycle assessment studies, mechanical recycling shows lower emissions than other approaches which is the most suitable method for environments. However, the mechanical properties of recycled products are much more degraded than virgin plastics. In this chapter, revolutionary plastic mechanical recycling is introduced. The new type of twin-screw extruder with the addition of molten resin reservoir unit is applied with various extrusion conditions. As a result, the mechanical properties of recycled products were recovered than its original materials. The relationship between recycling process condition, mechanical properties, and mesoscale lamellar structure are also discussed. It can be found that steady shear which is a conventional process affected the degradation of mechanical properties. In another way, re-extrusion by using a new type of twin-screw extrusion with a suitable processing condition is related to the regeneration of mechanical properties and lamellar structures similar to virgin plastics. This chapter is expected to introduce the recent advances in plastic mechanical recycling process and propose the future prospects of plastic recycling technology.

Part of the book: Recycling Strategy and Challenges Associated with Waste Management Towards Sustaining the World