Polymer chain conformations in hybrid composites of UHMWPE incorporated by GNP/MWCNT

A great many of important physical/chemical properties, containing thermal behavior and dynamic properties, are determined by polymer chain conformations. However, the cognition of how nanofillers impact polymer chains is still immature, especially for ultrahigh-molecular-weight polyethylene (UHMWPE) with extremely long molecular chains. Hence, cylindrical multi-walled carbon nanotubes (MWCNT) and lamellar graphene nanoplatelets (GNP) are applied to modify so as to investigate the effect of nanomaterials on UHMWPE chain conformations. The results of dynamic mechanical analysis authenticate that the less nanomaterials incorporated in UHMWPE enable to reduce the density of physical entanglement points, especially for the samples modified by GNP and MWCNT at the same time. Meanwhile, GNP and MWCNT added together in samples may also form a continuous structure, surrounding the UHMWPE molecular chains, and thus blocking the movement of the molecular chain. The reduction of physical entanglement points is beneficial to obtain a lower melting temperature, a higher crystallization temperature and an intenser molecular chains movement for UHMWPE composites. Compared with neat UHMWPE, the optimal performance of storage and loss modulus for UHMWPE/GNP/MWCNT composites is magnified by 169.33% and 100.01% respectively at 60 ℃, but both of them are much smaller than those of pure UHMWPE at higher than 140 ℃.