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GR-N Rubber

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  p363-364

2026-02-01

441

GR-N Rubber

polymerization very similarly to the butadiene–styrene copolymers. Similarly, “hot” and “cold” processes are employed. “Low,” “medium,” and “high” grades of solvent-resistant copolymers are formed, depending upon the amount of acrylonitrile in the copolymer that can range from 25 to 40%. The butadiene placement in these copolymers is approximately 77.5% trans-1,4, 12.5% cis-1,4, and 10% of 1,2-units. Also, the polymers formed by the “cold” process are less branched and have a narrower molecular weight distribution than those formed by the “hot” process. Aninteresting alternating copolymer of butadiene and acrylonitrile was developed in Japan [147]. The copolymer is formed with coordination catalysts consisting of AlR₃, AlCl₃, and VOCl3 in a suspension polymerization process. The product is more than 94% alternate and is reported to have very good mechanical properties and good oil resistance. Butadiene–acrylonitrile rubbers are another group of useful synthetic elastomers. These copolymers were originally developed in Germany where they were found superior in oil resistance to the butadiene–styrene rubbers. Commercially, these materials are produced by free-radical emulsion.