HETEROGENEOUS SULFOCHLORINATION OF POLYETHYLENE - EFFECT OF POLYMER MORPHOLOGY ON THE REACTION-RATES AND PROPERTIES OF REACTION-PRODUCTS

Polyethylenes of low, middle and high density have been submitted to heterogeneous sulphochlorination in the presence of hydroperoxides as initiators. Approximately equal amounts of SO2Cl and chlorine could be attached to the polyethylenic precursors. Although the reaction kinetics are strongly affected by the initial morphology of the substrates, it has been found that maximum amounts of the SO2Cl groups which can be introduced under such conditions are determined by the fraction of the amorphous material. The reaction kinetics are also strongly affected by the presence of antioxidants. X-ray diffraction analysis, birefringence and polarized i.r. measurements indicated that the morphology of the sulphochlorinated materials and of the products of their hydrolysis is strongly affected by the initial morphology of the polyethylenic precursors. Fluorescence probe measurements revealed that in highly oriented materials, the orientation of the amorphous regions is retained even upon water swelling of the final ion exchange membranes. It has been found that the initial morphology of the polyethylenic substrates together with the degree of the chemical modification (concentration of the introduced chlorine and SO2Cl groups) determine the properties of the products. © 1979.