Effect of oxygen on the polymerization of vinyl chloride. II. Polymer properties

The bulk and suspension polymerizations of vinyl chloride have been carried out in the presence of small known amounts of added oxygen at 54°C in the presence of peroxide initiators. The concentrations of oxygen were in the range 0–1240 ppm for 1‐gal bulk polymerization systems and 0–400 ppm for 15‐gal suspension polymerization systems. The thermal stabilities of the polymers prepared in the presence of oxygen were lower than those prepared under corresponding oxygen‐free conditions. The average molecular weights of bulk polymers isolated at relatively low conversions were reduced in the presence of oxygen, and the infrared spectra of the polymers were altered. The significance of the decreased thermal stabilities of the polymers prepared in the presence of oxygen is discussed briefly in relation to the possible sites of initiation of dehydrochlorination.