Does dynamic vulcanization induce phase separation?

Abstract

Immiscible and miscible blends of poly(vinylidene fluoride) (PVDF) and acrylic rubber (ACM) were subjected to dynamic vulcanization to investigate the effect of crosslinking on phase separation. As a result of different processability, mixing torque behavior of miscible and immiscible blends was significantly different from one another. Scanning electron microscopy (SEM) was used to investigate the morphology of the system. After dynamic vulcanization, submicron ACM droplets were observed in the samples near the binodal curve of the system under mixing conditions. Small angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) analysis were used to investigate the effect of dynamic vulcanization on the lamellar structure of the system. It was shown that for samples near the boundary of phase separation, increasing the crosslink density led to a decrease in the lamellar long period (L) as a sign of increment of crosslink density induced phase decomposition. Effects of shear rate on the final morphology of the system were investigated by changing the mixing temperature and by comparing the results of dynamic vulcanization at one phase and two phase regions.

Influence of network structure on the viscoelastic properties of dynamically vulcanized rubber/plastic blends: An alternative approach to understand the microstructure evolution

“…Figure 10(A), (B) and (C) represent the magnified view of the domain morphology of P33, P34 and P35 TPV systems respectively and the distribution of particle size M a n u s c r i p t 22 | P a g e for the respective TPVs is given in Figure 11. From these images it is evident that the dispersed rubber particles are actually the disintegrated rubber agglomerates containing nano-sized rubber particles ranging from 60-100 nm which is quite similar to the observation recently made by Wu et al [40] and Abolhasani et al [41]. For P33 TPV (Figure 10(A)), the rubber nano-particles are heavily shadowed by the S-EB-S phase due to the higher proportion of S-EB-S (60 weight percentage), which makes the rubber network less responsive during the scan resulting in poor quality photo-micrographs.…”

Effects of dynamic vulcanization on the kinetics of isothermal crystallization in a miscible polymeric blend

“…Recently, we have investigated miscibility of PVDF/ACM (acrylic rubber) blends and the influence of dynamic vulcanization on the processability and morphology of this system. 2,19,20 We demonstrated that PVDF and ACM are miscible in blends with more than 50% ACM. 2 We also showed that crosslinking reactions induced nano-phase separated droplets in blends near the binodal curve, whereas blends in the miscible area were miscible even after dynamic vulcanization.…”

“…2 We also showed that crosslinking reactions induced nano-phase separated droplets in blends near the binodal curve, whereas blends in the miscible area were miscible even after dynamic vulcanization. 20 In this study, we want to explore the complicated interrelationship between the crosslinking of amorphous components and crystallization kinetics of crystallizable polymers. It is anticipated that dynamic vulcanization affects the kinetics of crystallization significantly.…”

Preparation and properties of novel fluorosilicone thermoplastic vulcanizate with cross‐linking–controlled core‐shell structure

“…6,7 The effective way to prepare TPVs is through dynamical vulcanization, [8][9][10] which is the process of cross-linking an elastomer during its melt mixing with a molten plastic under dynamic condition. 11,12 A significant number of TPVs are produced through this method, such as polylactide (PLA)/natural rubber (NR), 13,14 PLA/epoxidized natural rubber (ENR), [15][16][17] PLA/nitrile butadiene rubber (NBR), 18 poly(vinylidene fluoride) (PVDF)/acrylic rubber (ACM), 19 ethylene-propylene-diene monomer (EPDM)/polypropylene (PP), [20][21][22][23] PVDF/ENR, 24 polyamide 12 (PA12)/hydrogenated acrylonitrile butadiene rubber (HNBR), 25 and ethylene octene copolymer (EOC)/poly dimethyl siloxane (PDMS) rubber. 26 The properties of TPVs strongly depended on the final morphology, which were affected by many factors, such as the cross-linking degree of the rubber phase, composition, viscosity and elasticity of individual components, preparation method, and processing condition.…”

“…The effective way to prepare TPVs is through dynamical vulcanization, which is the process of cross‐linking an elastomer during its melt mixing with a molten plastic under dynamic condition . A significant number of TPVs are produced through this method, such as polylactide (PLA)/natural rubber (NR), PLA/epoxidized natural rubber (ENR), PLA/nitrile butadiene rubber (NBR), poly(vinylidene fluoride) (PVDF)/acrylic rubber (ACM), ethylene‐propylene‐diene monomer (EPDM)/polypropylene (PP), PVDF/ENR, polyamide 12 (PA12)/hydrogenated acrylonitrile butadiene rubber (HNBR), and ethylene octene copolymer (EOC)/poly dimethyl siloxane (PDMS) rubber …”