Study of the physico-chemical properties of recycled polymers from waste electrical and electronic equipment (WEEE) sorted by high resolution near infrared devices

Abstract

Recycling of plastics from waste electrical and electronic equipment (WEEE) requires large scale high-performance sorting and identification technologies. The aim of this project is to evaluate the sorting performances of near infrared (NIR) devices, developed by the company PELLENC ST, for three styrenic polymers from WEEE: acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS) and ABS/polycarbonate blend (ABS/PC) and to study the physico-chemical properties of recycled materials. The use of an improved near infrared technique allows high levels of efficiency and performance to be achieved. This study can be used to evaluate the substitution ratio of virgin styrenic polymers by recycled ones for life cycle assessments (LCA) of reclaimed materials. Mechanical properties and fire properties of the sorted polymers were investigated. Mechanical properties of the polymers, particularly these of HIPS, were slightly modified after sorting. However, a degradation of the polybutadiene phase was observed. Fire tests revealed the presence of flame retardants in ABS and HIPS. Hence, NIR process could be used after a first sorting of brominated plastic wastes, in order to respect the RoHS directive. This project offers industrially viable alternatives for the recovery of plastics waste and the use of secondary raw materials.