The Consumption of Accelerator during Vulcanization

Abstract

Abstract THE so-called chemical theories of acceleration are based on the transformation of the accelerator during the process of vulcanization, but the quantitative study of such reactions is confronted by tremendous difficulties. From the increase in the amount of combined sulfur with time of cure, Hardman and White have drawn conclusions as to the relative stability of various accelerators. In these experiments they chose conditions which were specific for each accelerator, affording optimum effects. In the following work an attempt has been made to obtain some insight into the fate of the accelerator in the course of heating by a quantitative estimation according to the methods described below of the amount of accelerator found in the acetone extract of vulcanizates with increasing time of cure. In order to study the effect on the accelerator of various ingredients, the type of raw rubber, the quantity of sulfur, and the addition of fillers were considerably varied, while the ratio of accelerator to rubber remained constant.