Sintering and Processing-Dependent Mechanical Behavior of UHMWPE and Its Nanocomposites in the Presence of Microfine UHMWPE.

Research on ultrahigh-molecular-weight polyethylene (UHMWPE) nanocomposites has advanced toward multifunctionality, but mechanical properties remain limited by incomplete polymer fusion during sintering due to restrictions in polymer chain diffusion as well as nanoparticle agglomeration at the polymer particle interfaces. In this work, the sintering and processing-dependent mechanical behavior of UHMWPE and its nanocomposites with graphene nanoplatelets (GP) in the presence of microfine UHMWPE was investigated. Owing to their submicron size, the introduction of microfine UHMWPE promoted the formation of nanocomposites with a semisegregated structure that facilitated polymer fusion and enhanced mechanical properties. Increasing the sintering temperature further enhanced chain interdiffusion, resulting in significant strengthening in nanocomposites. Moreover, high-temperature uniaxial stretching demonstrated the potential of fabricating UHMWPE/GP nanocomposite tapes and fibers via a solvent-free route. Despite the presence of a high-aspect-ratio GP that typically hinders fusion, a high draw ratio was achieved in the presence of microfine UHMWPE, demonstrating its critical role in enabling both processability and mechanical reinforcement.