New Understanding of Morphology Evolution of Thermoplastic Vulcanizate (TPV) during Dynamic Vulcanization

Abstract

Thermoplastic vulcanizates (TPVs) have attracted considerable attention as typical "green" polymers in recent years and have been widely used in industry because they combine the excellent resilience of conventional elastomers and the easy recyclability of thermoplastics. With a new understanding of the formation and agglomeration of the rubber nanoparticles in ethylene propylene diene monomer/polypropylene (EPDM/PP) TPV, we revealed a new mechanism for the morphology evolution of TPV during dynamic vulcanization (DV). The phase inversion in TPV is dominated by the formation and agglomeration of the rubber nanoparticles rather than the elongation and breakup of the crosslinked rubber phase as previously reported. The size of the rubber agglomerates increases with increasing DV time and then remains constant after DV. In addition, we studied the relationship between the cross-linking of the rubber phase, formation and agglomeration of the rubber nanoparticles, and phase inversion and variation of the rubber network during DV. This study provides guidance to control the microstructure of TPV in preparation of high performance TPV products for automobile and electronic applications.

Property correlations for dynamically cured rice husk ash filled epoxidized natural rubber/thermoplastic polyurethane blends: Influences of RHA loading

“…It is clear that two-phase fine grained morphology was observed, with dark clusters for ENR domains and light regions for TPU phase. In these micrographs, it can be seen that the rubber particles were not spherical but were agglomerates of rubber micro-particles [41]. Incorporating 16 wt% RHA in the blend (Fig.…”

Theoretical and morphological evaluation of dynamic viscoelasticity and thermo-mechanical characteristics of TPV composites

“…The yellow and blue regions represent EOC and NR phases, respectively. This scheme is basically developed based on the model earlier proposed by Goharpey et al [25], however, it is actually in line with the model recently proposed by Wu et al [26]. It has been said that the spontaneous formation of rubber agglomerates from the rubber nanoparticles has led to the occurrence of phase inversion, which has been followed by the dispersion of the micrometre-sized rubber particles into the thermoplastic matrix due to the weakening of rubber network.…”

“…Therefore, the greater the difference in free energies, the higher is the tendency for the NR particles to agglomerate in EOC matrix to facilitate the phase inversion. Thus, it can rather be said that the influence of interfacial tension is more significant factor than the viscosity ratio of the rubber and thermoplastic phases [26,28] to explain the phase inversion phenomenon depicted by the TPVs. More precisely, it can be said that the phase inversion of the NR/EOC blend during dynamic vulcanization depends primarily on the formation and agglomeration of the rubber nanoparticles produced due to the change in interfacial tension between the NR and EOC phases.…”

The High Energy Irradiation Ageing of Reinforced Elastomers Based on Rubber Blends

“…Samples with flat surface were cut for hardness test (Durometer Model 306L Type A). Equilibrium swelling was carried out on uniform circular samples by the immersion method [3] in toluene. The samples were allowed to swell for two days until the equilibrium was reached.…”