Hot-pressing Fabrication and Multi-property Enhancement of Re2S3-modified Polycarbonate Composites (Re = Ce, Pr)

Introduction:: Polycarbonate (PC) components used in tribological and structural applications often suffer from insufficient wear resistance and thermal stability under coupled mechanical and thermal loads. This study investigated the effect of rare-earth sulfide fillers on the thermos-tribological properties of PC. Methods:: Cerium sulfide (Ce2S3) and praseodymium sulfide (Pr2S3) (denoted as Re2S3, Re = Ce, Pr) were introduced as functional fillers to modify PC, and Re2S3-PC composites with filler contents of 0-4 wt% were fabricated via a hot-pressing process. The thermal, mechanical, optical, and tribological properties of the composites, together with friction-induced structural and morphological changes, were investigated. Results:: The Re2S3 fillers not only enhanced the thermal stability, hardness, density, and ultraviolet (UV) absorption, but also reduced the friction coefficients of Ce2S3-PC composites under dry sliding conditions. Distinct differences between Ce2S3- and Pr2S3-modified systems are observed in their thermal decomposition behavior, indicating a filler-dependent regulation mechanism. Discussion:: Tribological analysis confirms that a Re2S3-derived lubricating and protective film forms on the worn surface. However, excessive load or sliding speed can disrupt the film. Besides the stability of the mechanical mixed layer is affected by the content of rare earth sulfide filler. Compared with existing PC-based composites, this work proposes a hot-pressing-enabled strategy for achieving multifunctional enhancement through rare-earth sulfide fillers, which integrates tribological, thermal, mechanical, and optical performance improvements within a single material system. Conclusion:: The Re2S3-PC composites exhibit strong potential for application in lightweight structural and functional components, such as sliding or bearing parts, protective housings, and optical/electronic enclosures that operate under coupled thermal, mechanical, and frictional conditions.