Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Post-consumer plastics recycling is strongly hampered by the fact that heterogeneous polymer feeds arex000D
intrinsically immiscible, which leads to phase separation within the mixture and typically very poor mechanicalx000D
properties for the recycled products. A well-established method to improve the degree of dispersion in polymerx000D
blends and to improve the mechanical properties is through the use of block and graft copolymer additives asx000D
compatibilizers. Unfortunately these materials are generally very expensive to synthesize, and therefore notx000D
amenable to large scale plastics recycling. We now suggest a methodology to generate graft copolymerx000D
compatibilizers in situ, based on a new cryogenic process developed by KWI Solutions Polymères to turnx000D
mixed plastic feeds into fine (1-5 micrometer) powders by mechanical fracturing in an extrusion process. Thisx000D
generates a large number of radical species at the surface of the particles, due to the polymer chain-breakingx000D
processes taking place in fracturation of the materials. We will investigate the use of mixed microstructurex000D
polyisoprene (PIP) as a post-fracturation additive to react with the free radical species present, to generatex000D
compatibilizing graft copolymers in situ during the extrusion process. The project will be concerned withx000D
generating PIP samples of different molecular weights, that can be used to optimize the extrusion conditionsx000D
and generate suitable compatibilizing agents. The performance of the additives will be evaluated in terms ofx000D
their ability to improve the tensile and impact properties of the blends obtained by that approach.