Block copolymer compatibilizers for improved polymer upcycling

Block copolymers increase the toughness of incompatible blends by stitching phase-separated polymer domains together. These materials could reduce the price of polymer upcycling by eliminating the need to sort mixed plastic waste. While experiments demonstrate that tetrablock copolymer compatibilizers increase incompatible blend toughness significantly, diblock copolymers do not. How do we optimize copolymer sequence to maximize blend toughness? Here, we investigate this question using coarse-grained molecular dynamics simulations in which we add various sequences of block copolymers to an incompatible polymer blend. We equilibrate, cool, and strain our simulations to failure in analogy to experiments. Our approach provides both rapid iteration of new compatibilizer sequences and access to microscopic data to reveal how toughness increases occur. This research will likely yield enhanced recycling techniques for a more sustainable future.