Fluoroalkylene ether silicate/Viton GLT blends: An approach toward improved low temperature flexibility

Abstract Low molecular weight fluoroalkylene ether silicate (FES) polymers demonstrating glass transition temperatures of −82°C to −91°C were obtained from the condensation polymerization of fluoroether bisdimethyl carbinols and bis(dimethylamino)methyl vinyl and dimethyl silane derivatives. Peroxide cure reactivity through the pendant vinyl moieties was demonstrated. In an effort to improve the low temperature flexibility of a peroxide curable fluorocarbon elastomer (Viton GLT from Du‐Pont), blends were prepared using the FES material as an additive cocuring plasticizer. Temperature retraction tests demonstrated an optimum 5°C (9°F) improvement in low temperature flexibility. The optimum blend formulation employed FES polymers with vinyl cure site concentrations ranging from 2.35 to 2.70 mol %. The optimum blend formulation maintained the strength and low compression set properties of the Viton GLT standard. These properties reflect sufficient cocuring between the FES and Viton GLT components to provide physical properties adequate for o ‐ring seal application. o ‐Ring seal evaluations in Freon E6.5 fluid (rod and piston seal tests) demonstrated some seal enhancement and comparable durability to standard Viton GLT o ‐rings.