Morphology development in thermoplastic vulcanizates (TPV): Dispersion mechanisms of a pre-crosslinked EPDM phase

Martin, Greg; Barrès, Claire; Sonntag, Philippe; Garois, Nicolas; Cassagnau, Philippe

doi:10.1016/j.eurpolymj.2009.07.012

Cited by 73 publications

(48 citation statements)

References 60 publications

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“…The diffusion coefficient of the blend at the melt processing temperature (200 o C) was estimated according to the considerations of Msakni and coworkers [24]. The shear rate of the internal mixer was 96 s −1 , based on reports in the literature [25]. The dispersion time for the DCP in the system under the processing conditions used was ∼3s.…”

Section: Resultsmentioning

confidence: 99%

Effect of dynamic crosslinking on phase morphology and mechanical properties of polyamide 6,12/ethylene vinyl acetate copolymer blends

Bondan

Bianchi

2015

Sci. cum Ind.

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The dynamic crosslinking of polyamide 6,12 and ethylene vinyl acetate (PA6,12/EVA) blends in the mixing chamber of a torque rheometer was investigated. EVA was selectively crosslinked within the PA6,12 phase through free radical reactions using dycumil peroxide. The degree of EVA crosslinking in the PA12,6/EVA materials was estimated based on the gel content (insoluble EVA fraction). The PA6,12/EVA phase morphology was investigated by scanning electron microscopy. The mechanical properties were investigated by determining the tensile strength and hardness. The half-life time (t 1/2 ) for homolytic scission of the dcumil peroxide (DCP) was 6s, and this time is longer than the dispersion time of the DCP in the blends. The addition of DCP resulted in increased torque values due to specific crosslinking in the EVA phase. For the pure EVA and its blends with PA6,12 the stabilized torque values increased proportionally with the amount of DCP in the system, due to a higher degree of crosslinking of the elastomeric phase. The gel content of the dynamically crosslinked blends increased with the amount of DCP incorporated until 4 phr. At 1 phr the gel content value was 2.6wt.%, while at 4 phr it was 17wt.%. For the polymer blend with 8 phr of DCP a lubricating effect contributed to reducing the gel content. The dynamically crosslinked blends, regardless of the amount of DCP added, showed a reduction in the mechanical properties, which is related to the morphological features of the system due to the low mechanical fragmentation during melt processing.

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Section: Resultsmentioning

confidence: 99%

Effect of dynamic crosslinking on phase morphology and mechanical properties of polyamide 6,12/ethylene vinyl acetate copolymer blends

Bondan

Bianchi

2015

Sci. cum Ind.

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“…At comparatively slower reaction rates, a smoother phase inversion with a better dispersion of elastomeric domains could be usually expected. With similar idea in mind, it has already been observed that the dispersion of a pre-cross-linked elastomer in a thermoplastic phase is a serious challenge especially when the gel content of the elastomer is larger than 70% [67]. Some other reactive systems other than thermoplastic/elastomer blends are as well shown to be affected by the effect of excessive gel content when dispersing one phase into the other.…”

Section: Morphology Development In Dynamically Vulcanized Nonplasticimentioning

confidence: 96%

Plasticization and Morphology Development in Dynamically Vulcanized Thermoplastic Elastomers

Shahbikian¹,

Carreau²

2015

Thermoplastic Elastomers - Synthesis and Applications

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Dynamically vulcanized thermoplastic elastomers constitute one of the main categories among various types of thermoplastic elastomers (TPEs). Due to the commercial importance of this particular group of TPEs, tremendous efforts have been dedicated to improve the understanding and control the phase morphology development. The ultimate goal is to obtain materials with improved physical and mechanical properties. As in other polymeric compounds, the parameters during the mixing stage have a significant influence on the final morphology of dynamically vulcanized blends. Furthermore, the phase morphology and, therefore, the distribution of elastomeric domains in the thermoplastic phase are also strongly dependent on the formulation. This chapter discusses the main important processing factors and, more specifically, highlights the effects of plasticization and curing on the morphology development of dynamically vulcanized thermoplastic elastomer blends. The following text provides fundamental information on how one should take into consideration each parameter affecting the morphology of nonreactive and reactive elastomer/thermoplastic blends.

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“…It has been reported that the cross-linking and breakup of the rubber phase is the primary factor responsible for the phase inversion of TPVs during dynamic vulcanization [17][18][19][20]. Several prior studies have been reported earlier describing the morphological evolution of the rubber phase in the TPVs during dynamic vulcanization [4,[21][22][23][24]. Some studies reported the effect of cross-linking and rapid increase in the viscosity on the morphology evolution [4,21] and some other reported the consequences of early stage crosslinking during in situ vulcanization and its induced effect on surface tension of the rubber phase leading to the breakdown of rubber agglomerates and dispersion of same in the thermoplastic matrix through the occurrence of phase inversion [23,24].…”

mentioning

confidence: 94%

“…Some studies reported the effect of cross-linking and rapid increase in the viscosity on the morphology evolution [4,21] and some other reported the consequences of early stage crosslinking during in situ vulcanization and its induced effect on surface tension of the rubber phase leading to the breakdown of rubber agglomerates and dispersion of same in the thermoplastic matrix through the occurrence of phase inversion [23,24]. Irrespective of the route of morphological evolution almost all studies reported the dispersion of micron-sized rubber particles (0.5-3.0 μm) in the thermoplastic matrix [4,21,23,24] which led to an improved mechanical and dynamic mechanical properties in terms of ultimate tensile strength and elastic recovery through hydrodynamic effect by acting as a soft filler in the thermoplastic matrix [22,25].…”

mentioning

confidence: 97%

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

Dey

Naskar

Dash³

et al. 2014

Materials Today Communications

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Morphology development in thermoplastic vulcanizates (TPV): Dispersion mechanisms of a pre-crosslinked EPDM phase

Cited by 73 publications

References 60 publications

Effect of dynamic crosslinking on phase morphology and mechanical properties of polyamide 6,12/ethylene vinyl acetate copolymer blends

Effect of dynamic crosslinking on phase morphology and mechanical properties of polyamide 6,12/ethylene vinyl acetate copolymer blends

Plasticization and Morphology Development in Dynamically Vulcanized Thermoplastic Elastomers

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

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