The Development of Elastomer Rheological Processability Quality Control Instruments

Abstract

Abstract We have surveyed the development of processability measurements from its origins, about 1920, to the present. We have followed the factors—technology, scientific, and political—which have caused its evolutions. The earliest instruments the capillary and compression rheometer, are still with us. As early as the mid 1930s, different traditions developed in the United States and Germany, differences which continue to the present day. These were accentuated by the development of synthetic rubber and World War II. The Germany industry used the Defo compression instrument and the Americans decided on the Mooney shearing disc viscometer. The early postwar period saw a temporary withdrawal of German activity and an American interest in stress relaxation measurements with a biconical stress relaxation instrument being made semi-commercial by B. F. Goodrich in the 1970s. B. F. Goodrich has continued to improve this instrument over the past generation. The post-1975 period has also seen increased activity in Germany; Bayer AG(i) redesigned the Defo instrument and had it commercialized by Haake and (ii) devised a Mooney post-shearing stress relaxation measurement which has been commercially developed by Monsanto. A pressure-controlled rotational rheometer has been developed by Avon Rubber which allows for better study and characterization of slip. The development of instruments has been coupled with growing knowledge of the rheological properties of gum elastomers and carbon black compounds.