Contamination in recycling thermoplastics used for manufacturing of consumer durable products

Diminishing land fill capacity and increased volume of waste consumer durable products are the main drivers for the recycling of engineering thermoplastics. Consumer durables focused on in this study include long term products, specifically waste electrical and electronic equipment (WEEE). WEEE can be recycled in bulk or as separated components of a disassembled machine. Bulk recycling with limited sorting is the economically preferred option however, blending incompatible plastics, without modification, often limits the end use of the recycled plastics. The decision to apply expensive sorting techniques at the end of a products life should be based on processability and mechanical properties of the engineering thermoplastics contaminated by other polymeric materials. This project investigates the thermal, rheological and mechanical properties of a range of binary blends of recycled thermoplastics. An amorphous polymer, Acrylonitrile-Butadiene-Styrene (ABS), and a semi-crystalline polymer, Polypropylene (PP), have been blended with contaminant amounts (0-30%) of other amorphous and crystalline polymers. Models were developed for the prediction of the properties as a function of contamination level. The results show that generally, these thermoplastics should be separated prior to processing to optimize the properties of the recycled plastics. However, the properties for some of the blends with a certain level of contamination are sufficient, such that they can be used for various applications where the use of sorting techniques is not economically viable.