Making sense of plastics recycling

Major benefits of plastics recycling are reduced depletion of non-renewable resources and reduction of world-wide waste. Traditional thermo-mechanical recycling causes reduction of mechanical properties for most thermoplastics. Down-cycled materials may nevertheless be suited for certain useful applications. Developing such applications may be a step towards more effective future use of resources. Increased application of recycled thermoplastics is generally preferable over landfills, or waste lying around in some parts of the world. Different recycled high-impact polystyrenes (HIPS) from TVs were mechanically tested, as well as mixtures of them. Mixtures of a low-density polyethylene (LDPE) and a polypropylene (PP) were tested as well, representing a large portion of mixed plastics waste. A contribution was made to a process improvement for creating products from street waste in Kenya. Mixing different recycled HIPS grades gave no significant changes in melt flow index and impact strength. One mixture showed a significant reduction in tensile strength. In PP-LDPE mixtures there was an indication of improved mechanical impact resistance of the PP by addition of LDPE in several percentages. In Kenya a separation process utilizing simple equipmen