Influence of a crosslinked system on the morphology and properties of TPVs based on PA/NBR

Abstract

The mechanical properties of thermoplastic vulcanizates (TPVs), depend strongly on their morphologies, which themselves depend on the properties of the primary polymers, the composition of the TPV, and the crosslink system and crosslink process. The morphology is defined during the dynamic vulcanization. This work deals with the study of the influence of crosslink systems on TPVs based on PA/NBR (copolyamide PA6/6-6 and nitrile rubber) in a 40/60 composition. Dicumyl peroxide, bismaleimide, phenolic resin, a sulfur-accelerated system, and dicumyl peroxide with two coagents were used as crosslinkers. TPVs were characterized by taking into account their mechanical strength, solvent resistance, compression set, and morphology. The curing system constituted by dicumyl peroxide and sulfur/bismaleimide as coagents resulted in a more defined morphology, and therefore the TPV exhibited the best properties. For these TPVs, a morphology consisting of spherical domains of rubber distributed homogeneously on the polyamide matrix could be observed.

Effect of different curing systems on cell structure, mechanical properties and aging resistance of nitrile butadiene rubber foam coating with liquid compounds

“…This result was also described and observed for NBR rubber by El-Nemr 8 and Fagundes and Jacobi. 12 Because of the higher cross-link density, the S/DCP system exhibited a low value for the elongation compared to the DCP system at lower cross-linker content (Fig. 6).…”

“…Obviously, the cross-link structure and cross-link density affected the tensile properties of NBR foams, depending on the type of curing system. 8,12 As for S/DCP systems, it both had C-C and S-S bonds. The C-C bond having high bond energy could first endure stress and fracture at low elongation; meanwhile, stress could be transmitted and rearranged to obtain a homogeneous distribution by S-S bonds.…”

“…6,[8][9][10] Whereas few results were reported concerning the combined curing agent of S with DCP. 11,12 It was useful to form a complex cross-link structure including S-S and C-C linkage in the elastomer matrix for improving the mechanical property and processability of single peroxide cured foams. Furthermore, it would increase the cross-link efficiency of the vulcanisation process as well as the cross-link density.…”

The formation of fibrous structure of polyamide 6 induced by the three‐step forming process and its prominent reinforcement in nitrile rubber

“…In recent years, PA6/NBR blends own excellent oil resistance, high‐temperature resistance, and mechanical properties, and its research has caused wide concern . Fagundes and Jacobi et al . studied the effects of different crosslinking systems on the morphology and mechanical properties of PA6/NBR blends.…”

Dynamically vulcanized acrylonitrile–butadiene–styrene terpolymer/nitrile butadiene rubber blends compatibilized by chlorinated polyethylene

“…Tian et al investigated the influence of compatibility on crystallization behavior and morphology of polypropylene in PP/NBR TPVs. Fagundes and Jacobi reported the influence of a crosslinked system on the morphology and properties of TPVs based on polyamide (PA)/NBR, and the effect of dynamic vulcanization on the properties and morphology of PA/SAN/NBR blends was also investigated . Zhang et al studied the compatibility and physical properties of chlorinated polyethylene rubber (CM)/NBR blends.…”