Chemical Recycling of Polycarbonate Acrylonitrile Butadiene Styrene Blends via Organocatalyzed Acetolysis

Polycarbonate acrylonitrile butadiene styrene (PC/ABS) is one of the most widely used plastic blends, with growing importance in both automotive and electronics applications. However, its heterogeneous nature disables recycling, leading to its disposal via landfilling or incineration. This work proposes a way to recycle this material via selective chemical recycling whereby the PC is depolymerized by acetolysis, heating the blend with acetic acid and a basic organocatalyst, leaving the ABS untouched. Catalytic optimization on PC feedstocks revealed that successful organocatalysts required not only sufficient basicity but also a basic nitrogen incorporated within an aromatic ring. A kinetic study revealed the depolymerization was pseudo first-order with an activation energy of 96.7 kJ mol^-1. Selective acetolysis was developed for both PC/ABS pellets and a PC/ABS automotive part. Separation of the PC monomers from the ABS was achieved with dialysis, with isolated ABS having similar properties to virgin grades. This approach offers a promising route toward recovering value from recalcitrant PC/ABS blends by enabling selective deconstruction of PC and recovery of ABS, thereby minimizing dependence on virgin plastic production.