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

Abstract

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 thermooxidative 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.

Thermoplastic vulcanizates with an integration of good mechanical performance and excellent resistance to high temperature and oil based on HNBR/TPEE

“…In the final stage of mixing, the torque of all TPVs remained steady after a continuous decline, indicating that the dynamic vulcanization process had been completed and thus presumably the phase inversion occurred, during which the cross-linked HNBR broke up into particles and dispersed in TPEE phase by the shearing action. The torque curve of HNBR/TPEE TPV are coincide with the typical torque variation of dynamically vulcanized TPVs with peroxide cross-linking, 35,36 meaning that the TPVs of this system has successfully achieved dynamic vulcanization.…”

“…Notably, the enhancement in TS and EB of TPVs after aging is attributed to the further vulcanization of the HNBR under 125°C. During the thermo‐oxidative aging process, the peroxide is further decomposed and slowly released to the extent that the cross‐linking degree of HNBR increases again, achieving a secondary vulcanization of the rubber and resulting in improved mechanical properties of the TPV, as can be corroborated by the aging results of static vulcanized HNBR control samples 1,35 …”

Contribution of surface silanization process on mechanical characteristics of TPU‐based composites involving feldspar and quartz minerals

“…The integration of mineral particles led to expanding the local free volume in composite structure by improvement in the movement of PU chains. [ 57–60 ] Silane‐treated QRZ and FLS samples gave relatively lower MFI values according to their untreated samples. As an overall conclusion from these results, it can be said that QRZ and FLS additions yielded no indicative problems in the case of processing stages of TPU‐based composites because similar MFI values were observed.…”

Development of thermoplastic vulcanizates based on in situ synthesized thermoplastic polyurethane and acrylonitrile-butadiene rubber: the influence of the curing system

“…The mechanical properties of TPU/(E) NR blends are often improved by using fillers of natural origin, such as rice husk ash or kenaf fiber [19,20]. In TPU/ methyl vinyl silicone rubber (MVQ) based thermoplastic vulcanizates have shown that both the type and the amount of peroxide used as a vulcanizing agent have a significant effect on the properties of blends [21].…”