(538j) Recycling of Plastic Waste Using Dissolution/Precipitation

Plastics are widely used across industries such as food, beverage, textile, healthcare, automotive, aerospace, construction, agriculture, and oil. Only a small fraction of the plastics produced is being recycled, with the great majority landfilled or released into the environment. There is great interest nowadays in increasing the recycling of plastic waste. Mechanical recycling is used to recycle plastic waste, however, this method is efficient only for homogeneous and non-contaminated plastic waste, and for easily identifiable objects such as bottles made of PET or HDPE. A solution for recycling many of the plastics which mechanical recycling fails to process comes from chemical recycling, which typically involves the deconstruction of polymers to monomers or to intermediates that can be used as fuel or chemical feedstock. These, however, result in undesirable greenhouse gas (GHG) emissions. The focus of our research is on dissolution/precipitation as a promising, low-GHG methodology for recycling waste plastic. Through this method, individual polymers can be separated from mixtures or blends, purified from additives or fillers, reduced in volume, and obtained in an acceptable form without negatively affecting the properties of the original polymers. Examples are presented on polyolefin recovery from dissolution/precipitation using environmentally responsible solvents, and processing conditions for efficient recovery are discussed.