Thermal degradation of polymers during their mechanical recycling

Abstract

This chapter deals with thermal degradation processes occurring during polymer recycling by melt re-processing, i.e. mechanical recycling. Some general aspects of polymer processing are first recalled. Then, thermal degradation mechanisms and kinetics are described, and the main processing methods are compared from this point of view. Temperature-molar mass maps allow to define a processability window and to envisage industrial ways (in particular, the use of processing aids and thermal stabilizers) to widen this window. The end of this chapter is devoted to a case study: PET mechanical recycling by extrusion molding, which is characterized by an especially complex combination of degradation processes.