Filler Influence on H2 Permeation Properties in Sulfur-CrossLinked Ethylene Propylene Diene Monomer Polymers Blended with Different Concentrations of Carbon Black and Silica Fillers.

Jae Kap Jung,Chang Hoon Lee,Un Bong Baek,Myung Chan Choi,Jong Woo Bae

doi:10.3390/polym14030592

Abstract

Filler effects on H2 permeation properties in sulfur-crosslinked ethylene propylene diene monomer (EPDM) polymers blended with two kinds of carbon black (CB) and silica fillers at different contents of 20 phr–60 phr are investigated by employing volumetric analysis in the pressure exposure range of 1.2 MPa~9.0 MPa. A linear relationship is observed between the sorbed amount and pressure for H2 gas, which is indicative of Henry’s law behavior. The hydrogen solubility of EPDM composites increases linearly with increasing filler content. The magnitude of hydrogen solubility for the filled EPDM composites is dependent on the filler type. The hydrogen solubility is divided into two contributions: hydrogen absorption in the EPDM polymer and hydrogen adsorption at the filler surface. Neat EPDM reveals pressure-dependent bulk diffusion behavior. However, with increasing filler content, the diffusivity for the filled EPDM composites is found to be independent of pressure. The magnitude of filler effects on the hydrogen permeation parameter is measured in the order of high abrasion furnace CB~semireinforcing furnace CB ˃ silica, whose effect is related to the specific surface area of CB particles and interfacial structure. The correlation between the permeation parameters and filler content (or crosslink density) is discussed.

Highlights

Ethylene propylene diene monomer (EPDM) [1,2,3] is a type of synthetic rubber made from ethylene, propylene, and a diene comonomer that enables crosslinking via sulfur vulcanization
We measured the hydrogen emission content versus the elapsed time after decompression in the pressure range from 1.2 MPa to 9 MPa for neat EPDM and nine cylindrical EPDM composites filled with carbon black (CB) and silica
Filler effects on H2 pressure-dependent permeation properties for neat EPDM and EPDM blended with CB and silica fillers are systematically investigated in the pressure range of 1.2 MPa~9 MPa

Summary

Introduction

Ethylene propylene diene monomer (EPDM) [1,2,3] is a type of synthetic rubber made from ethylene, propylene, and a diene comonomer that enables crosslinking via sulfur vulcanization. EPDM is always used compounded with fillers, such as carbon black (CB) and silica, and with plasticizers, such as paraffinic oils This material has useful rubbery properties only when crosslinked. EPDM elastomers have been proven to be useful gas barrier materials in the automotive, electrical, and industrial construction industries due to their unique mechanical and chemical properties [4,5,6,7]. Their applications include radiator and heater hoses, window and door seals, O-rings and gaskets, accumulator bladders, wire and cable connectors and insulators, diaphragms, and weather stripping. The typical working temperature range is relatively wide, from −45 ◦C to +150 ◦C, because the glass transition occurs at low temperatures

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