Effect of epoxy resin on the thermal behaviors and viscoelastic properties of poly(phenylene sulfide)

In this work, thermal behaviors and viscoelasticity of the PPS/epoxy resin mixtures prepared by melt mixing were studied, and the rheology was used as a tool to further explore the relation between chain structures and properties of the mixtures. The results show that the epoxy resin can promotes degradation and branching of the PPS during melt mixing due to its poor thermal stability. The formation of long chain branched and partly crosslinked structures in the mixtures together with the residual decomposed components hence result in broadening of molecular weight distribution in comparison with those of the neat PPS. As a consequence, the mixtures show the viscoelastic behaviors far different from the neat PPS: the presence of crosslinked structure leads to the strong solid-like responses in the small amplitude oscillatory shear (SAOS) flow, and the presence of long chain branched structure to the weak strain overshoots in the large amplitude oscillatory shear (LAOS) flow. Moreover, after quiescent annealing, a strain-scaling transient stress behavior is observed in the mixtures in the reverse flow.

► Melt mixing with epoxy results in formation of LCB and crosslinked PPS.
► The mixture shows a solid-like response during SAOS flow while neat PPS does not.
► LCB structure in PPS shows a weak strain overshoot during LAOS flow.
► Crosslinked structure presents a transient stress overshoot during reverse flow.