Effect of hard segments on the thermal and mechanical behaviour of a novel hybrid silicon thermoplastic elastomer

Abstract

A novel hybrid organic silicon thermoplastic elastomer (Si-TPE) was copolymerized by adopting branched organic polysiloxane and diphenyl methane diisocyanate, and the thermal processing mechanism and the effect of hard segments on the thermal processability and mechanical properties of Si-TPE were studied. The results showed that Si-TPE presents excellent thermal processability ascribed to its reversible physical crosslinking, i.e. hydrogen bonding between NH-C=O of the hard chains, and could be stably thermally processed into different products including films, tubes, tapes and sheets at 160-180 °C. With increasing hard segment content, the hydrogen bonding in the system was enhanced, leading to increases in both the melt viscosity and the softening temperature of Si-TPE. Simultaneously, the mechanical properties of Si-TPE were improved. When the hard segments increased to 20.3%, the tensile strength and Young's modulus of Si-TPE reached 13.4 MPa and 43.8 MPa, respectively.