Beiträge zur Chemie des Kautschuks. V. Über die Umsetzung des Kautschuks mit Schwefelchlorür und Schwefel

The Chemistry of Rubber.

“…It can be obtained pure as a brown, insoluble powder by heating a cumene solution of purified rubber and a large excess of sulfur for several hours at 170°C. (144). Sulfur does not add at all, or certainly not to any perceptible extent, at room temperature.…”

“…When an excess of the theoretical amount for saturating each double bond is used, there is obtained, according to Weber (152), (C6H8SC1)X, or as expressed by him, Ci0Hi6S2C12. According to Hinrichsen and Kindscher (144), only half of this amount of sulfur monochloride is added; in other words, the product is (Ci0Hi6)2S2C12 or (CioH16SC1)x; and Bernstein (153) claims to have verified this. Weber gives a complete elemental analysis which agrees very well with the theoretical calculations for his formula.…”

IV—A Theory of Vulcanization of Rubber

“…The ultimate product of this addition has one atom of sulfur for each isoprene unit (65). There has been a controversy of long standing over this point (27,29,33,50,59,67), but it seems well established that the formula for ebonite is (CjHsS),.. Under certain conditions substitution of hydrogen may take place to raise the sulfur content above that called for by the formula (60) but this is unusual and not a part of vulcanization.…”