Relationship between strain rate, temperature, and impact failure mechanism for poly(vinyl chloride) and poly(ethylene terephthalate)

Abstract

AbstractOne approach to the purification of recycled thermoplastic mixtures is selective grinding to induce differences in sizes and shapes between polymers with different compositions. These mixtures can then be separated using one of several technologies including conventional sieving or hydrocyclones. Recycled poly(vinyl chloride) and poly(ethylene terephthalate) often are cross‐contaminated with each other since they have overlapping density ranges and are very difficult to separate using methods such as flotation. Selective grinding followed by physical separation might be a preferred method for separating such a polymer pair if processing “windows” for inducing differences in failure mechanisms can be found. There is a temperature range over which PET fails in a ductile mode while PVC fails in a brittle mode for impact grinding experiments. This range is not accurately predicted by failure mechanism and β‐transition temperature diagrams.