High flex, ozone-resistant polymers of higher α-olefins†

Ozone resistance and high flex life are some of the important features of elastomers needed in the rubber industry. EPDM, a terpolymer of ethylene, propylene, and small amounts of a nonconjugated diene, has a saturated carbon-carbon backbone and therefore shows excellent resistance to ozone and aging, and good flex properties. However, butyl rubber (1IR) has a small amount of unsaturation in its carbon-carbon backbone and consequently does not exhibit as good ozone resistance and aging characteristics as EPDM. We discovered a family of new rubbers named Hexsyn^TM, which were synthesized by copolymerizing higher α-olefins (C₄-C₁₀) with a mixture of 4-methyl- and 5-methyl-1,4-hexadienes. One outstanding Hexsyn™ rubber is a copolymer of 4-hexene and the 5-methyl-1,4-hexadiene. This copolymer uniquely combines the useful properties of EPDM and butyl. Outstanding features are excellent flex life, excellent ozone resistance, good compression set resistance, and high damping.

Due to its excellent flex life, Hexsyn^TM( (hexene copolymer) has been found useful in fabricating experimental pumping diaphragms of air-driven artificial hearts of calves and also for left ventricle assist devices. This rubber has found application as a flexing element in artificial finger joints for damaged or diseased human fingers.