Low‐fuel‐permeation thermoplastic vulcanizates prepared from mutually miscible fluoroelastomer and poly(vinylidene fluoride–hexafluoropropylene)

Abstract

An oleophobic barrier material is imperative for automotive fuel hose applications to reduce permeation of air-polluting hydrocarbons. With the increasingly strict exhaust emission regulations, the development of new fluoroelastomer (FKM) materials with enhanced fuel permeation resistance is highly desirable. Herein, we successfully developed a class of all-fluorinated thermoplastic vulcanizates (TPVs) by dynamic vulcanization from FKM and poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)). The mechanical properties, recyclability and fuel resistance of the FKM/P(VDF-HFP) TPVs were examined. The results show that the FKM/P(VDF-HFP) blends present high mechanical performance with tensile strength up to 26.3 MPa and strain at break of more than 600% at a high rubber/plastic ratio of 7:3 by weight. Moreover, our FKM/P(VDF-HFP) TPVs show excellent fuel resistance and recyclability. Such high mechanical properties, recyclability and fuel resistance are correlated with the good miscibility between FKM and P(VDF-HFP), the strong FKM rubber network and the fine phase morphology of TPVs. This work provides a guidance for the preparation of new TPVs through selecting mutually miscible polymers without any compatibilizer, and demonstrates that these new TPVs can be a good alternative option to replace the traditional thermosetting fluororubbers in the automotive industry as barrier layers for fuel hoses.

Fluorination Modification of Methyl Vinyl Silicone Rubber and Its Compatibilization Effect on Fluorine/Silicone Rubber Composites

“…Among them, the F atom in FKM with a relatively small radius can be closely arranged around the carbon atom and form a protective barrier for the C–C bond due to the strong electron-absorbing effect of the F atom. The narrowed length and increase in bond energy of the C–C bond would confer the fluorine-containing polymer elastomers with chemical inertia of the carbon chain, heat resistance, oxidation resistance, oil resistance, and other properties. − After blending with silicone rubber, the fluorine/silicone rubber composite material combines the advantages of silicone rubber and fluorine rubber, with good resistance to high and low temperatures and oil resistance, , while reducing the cost of use. However, because of the large difference in polarity between these two kinds of rubbers, the compatibility of fluorine/silicone phases is poor, which affects the blending effect and performance. , The addition of a third component compatibilizer might be a simple and effective way to achieve a more homogeneous fluorine/silicon blend system.…”

Special issue: polymer science and engineering of elastomers stretching elastomers to their limits

“…Fluoroelastomers are described with a focus on their miscible blends to prepare low-fuel permeation crosslinked networks. 8 Sustainability remains at the forefront of our research efforts, and the incorporation of sites for depolymerization continue to receive intense attention. It is widely recognized that the ester carbonyl represents an electrophilic site that is amenable to hydrolysis, methanolysis, and glycolysis using both chemo-and bio-catalytic pathways.…”