Low Temperature Manufacture of Chemical Rubber

Abstract

The fundamental basis for the successful development of low temperature rubber after the end of the war lay largely in the use of systems employing what are currently termed "speed-up" chemicals to increase the rate of polymerization at low temperatures. Stewart and Fryling (40) reported early in 1943 the use of certain redox systems in speeding up the polymerization of GR-S. The German experience with low temperature recipes has been reported by Livingston (38). In 1945 patents were issued to Fryling (14) and Stewart (39, 41) of The B. F. Goodrich Co., covering such systems. Goodyear reported in early 1946 to Rubber Reserve (18) that similar studies had been carried out in its laboratories before the war.These systems involved the use of,both an oxidizing and a reducing agent. Other patents covering systems of oxidizingreducing agents have been issued in this country and in France and Germany (4,10,44,46)• The teams of the U. S. Technical Missions to Europe in 1945-46 brought back to the United States reports (34, 39, 4?) of German work on chemical rubber; these included work on a redox polymerization system, briefly reported by Weidlein (45). Actually the use of a redox system in chemical rubber manufacture was developed independently by scientists in England, Germany, and the United States, but the work in England was fundamental research and that in Germany had not. progressed beyond the laboratory or pilot plant stage.

Assessment of 1,3-Butadiene Epidemiology Studies

“…This increased production capacity and decreased the need for opening and closing the reactor system. By May of 1948, continuous polymerization was in operation at all of the larger plants (10). The second refinement was based on the discovery of polymerization initiators, such as diazothioethers that allowed the polymerization to be carried out at temperatures of 50C and below.…”

“…The second refinement was based on the discovery of polymerization initiators, such as diazothioethers that allowed the polymerization to be carried out at temperatures of 50C and below. The first large-scale production of cold rubber, that is, SBR produced at low reaction temperatures, was carried out in February of 1948 (10). This development generally followed the conversion to continuous processes.…”

Butadiene Polymers and Polyisoprene - Prepared By Alfin and Emulsion Processes

“…The crystallizability, as measured by total observed volume decrease, was 3.9 X 10_8cc. per gram after 24 hours' equilibration at -20°C. This value represented only a moderate change and indicated that the polymer was crystalline at room temperature.…”

“…laboratory manual) was vacuum distilled at 20 to 30 mm. of mercury pressure and used within 24 hours. The particular Alfin catalyst used in this work was prepared by A.…”

Emulsion Polymerizations at Low Temperatures

“…Later, Semon and Fryling (18) proposed and demonstrated the possibilities of certain water-soluble and oil-soluble aliphatic diazo compounds as initiators. In 1944, W. B. Reynolds and E. W. Cotton (19), in an attempt to combine the functions of initiator and modifier in one molecule, discovered the extraordinary initiating activity of diazo thio ethers. Kolthoff and Dale (14) reported that potassium ferricyanide further activated diazo thio ethers at 30°C.…”