Systematic investigation on the effect of crosslinking agent type and dosage on the performance of TPU/MVQ based thermoplastic vulcanizates

Dynamic vulcanized thermoplastic polyurethane (TPU)/methyl vinyl silicone rubber (MVQ) thermoplastic vulcanizates (TPVs) were prepared in torque rheometer. The influence of the type and amount of peroxide crosslinking agent on the mechanical properties, thermal stability, micromorphology and melt flowability was systematically investigated. The results showed that the mechanical properties of the TPVs vulcanized by 2,5-dimethyl-2,5-di (tert-butyl peroxy) hexane (DBPH) first increased and then decreased with increasing the peroxide amount, while for dicumyl peroxide (DCP) vulcanizing system the mechanical properties slowly increased. Besides, the comprehensive mechanical properties vulcanized by DBPH were better than those of DCP group. The results of the thermogravimetric analysis showed that the TPVs vulcanized by DBPH had better heat stability, corresponding to the excellent thermo-oxidative aging performance and the 38% increase in tensile strength after aging. In addition, the MVQ rubber particles showed better dispersing performance for DBPH vulcanizing system. The melt flow rate of the TPVs showed a linear relationship with increasing DBPH dosage and became worse after the amount of crosslinking agent exceeded 1.5 phr. By comprehensive comparison, the TPVs have better performance when use peroxide DBPH as the crosslinking agent and the dosage is 1.5 phr.

Automated summary

The mechanical properties, thermal stability, micromorphology, and melt flowability of TPU/MVQ TPVs vulcanized by different peroxide crosslinking agents were systematically investigated. TPVs vulcanized by DBPH showed better overall performance, with improved mechanical properties, thermal stability, aging resistance, and better dispersion of MVQ rubber particles. The melt flow rate of TPVs had a linear relationship with increasing DBPH dosage, but deteriorated after exceeding 1.5 phr of the crosslinking agent. Overall, TPVs performed better when using DBPH as the crosslinking agent at a dosage of 1.5 phr.