Mechanical reprocessing of polyolefin waste: A review

Efficient technology and applications for recycled polymer waste has become increasingly important to decrease environmental contamination and to conserve nonrenewable fossil fuels. Mechanical recycling is the most widely practiced in Australia, since it is relatively easy and economic; and moreover, infrastructure for collection and reprocessing has been well established. In order to improve quality of end products of recycled plastics, various workable reprocessing techniques in the second stage of mechanical recycling have been developed and widely applied in the recycling industry. This article critically reviews the current reprocessing techniques of recycled polyolefins. Reprocessing recycled polyolefins is always accompanied with degradation, crystallization, and consequent processability problems, which result from molecular chain scission, branching, and crosslinking. The present state of knowledge and technology of various reprocessing techniques, including melt blending, filler reinforcement and mechanochemistry, is then described and evaluated systematically. Each reprocessing technique presents its own individual advantages and special applications. POLYM. ENG. SCI., 55:2899–2909, 2015. © 2015 Society of Plastics Engineers