Preparation of chlorosulfonated polyethylene by the gas-solid method

Chlorosulfonated polyethylene (CSM) has been prepared by the gas-solid meth od in a tank reactor using chlorinated polyethylene (CPE) and a gaseous mix ture of chlorine and dioxide sulfur. Sulfur content of CSM determined by el ement analysis is used as a reference for the quantitative determination of the degree of chlorosulfonation. The effects of reaction temperature, effe ctive gaseous mixture concentration, particle size of CPE, and the ratio of chlorine to dioxide sulfur on chlorosulfonation are investigated. The resu lts indicate that with the increment of reaction temperature within the ran ge of from 30 to 50 degreesC, the rate of chlorosulfonation during the late r reaction period (15-25 min) is markedly increased and the prepared CSM ha s higher sulfur content. it was also found that the rate of chlorosulfonati on increases with the effective gaseous mixture concentration, and that the ratio of chlorine to dioxide sulfur is preferably 1 : 1. It was proven tha t HCl, by-product of the chlorosulfonation, can accelerate the rate of chlo rosulfonation when the volume concentration of HCl is lower than 40%, and t hat the presence of oxide results in higher sulfur content of the resultant CSM. (C) 2001 John Wiley & Sons, Inc.