The Effect of Polycrystalline Nanoscale Zinc Sulfide on the Molecular Weight and Properties of Polycarbonate

Bis(4‐(2‐hydroxyethoxy)phenyl)fluorene polycarbonate is a transparent thermoplastic resin characterized by a high refractive index and low birefringence, yet it has a relatively low molecular weight. To further increase the polymer's molecular weight, this study synthesized α‐ZnS and β‐ZnS, along with their coexisting phase, through a precipitation method to catalyze the transesterification polycondensation of bisphenol A (BPA), 9,9‐bis[4‐(2‐hydroxyethoxy)phenyl]fluorene (BPEF), and diphenyl carbonate (DPC) via melt ester exchange polycondensation. It was found that the acidic sites generated during calcination contribute to enhanced catalytic activity, leading to a high‐molecular‐weight polycarbonate ( M w = 87,363). Concurrently, the tensile strength (89.02 MPa) increased as the molecular weight rose. Notably, varying the ZnS content (0.085–1.67 g/kg) in the incorporated polycrystalline phase not only effectively catalyzed the polymerization reaction but also increased the refractive index without significantly affecting the transmittance.