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Butadiene-acrylonitrile copolymers have been the preferred general purpose oil and fuel resistant elastomers in automotive, aircraft and industrial product applications for over 30 years. The need for improved service performance to meet more severe and/or newly emerging service requirements has prompted a number of studies to improve the performance of these polymers. This work has led to the development of a family of new and unique polymerization bound antioxidant stabilized nitrile rubbers which have outstanding heat resistance characteristics. These new rubbers also retain their age resistance qualities after exposure to oils or fuels which can extract the protective antioxidants from conventional nitrile rubbers thereby contributing to early failure of parts in service.

The Automotive Industry has expressed concern that fuel hose performance must be improved to withstand highly aromatic fuels, sour gasoline exposure, fuel permeation loss, and more rigorous service conditions. Closer co-operation with polymer producers is required in optimizing performance. This report concerning the resistance of polymers to various fuels, including alcohol modification, is the result of a study to optimize properties of nitrile rubbers. It indicates that a 39% acrylonitrile CHEMIGUM HR-365* bound antioxidant nitrile rubber tube should achieve a balance of long term heat aging, fuel permeation resistance, and -25°C to -30°C flexibility. Coupled with a CO or CSM jacket, this type of hose should be far more economical than CFM fluoroelastomer and still resist vibration affects as low as -40°C.

Increasing performance requirements have prompted numerous studies to improve the aging of NBR. The Goodyear Tire & Rubber Company has developed a family of polymerization bound antioxidant stabilized CHEMIGUM * rubbers which have superior heat, abrasion, compression set resistance, and persistent non-volatile or extractable antioxidant protection. These polymers are being evaluated as alternatives to conventional NBR, ECO, PA, silicone and fluorocarbon polymers in applications such as power steering and transmission seals, fuel hose and compressor seals. More costly polymers have previously displaced conventional NBR in some of these applications. NBR warrants reevaluation due to the current world energy situation where there is a need to apply new technology, and lowest cost polymer systems to their fullest potential.