Study of dehydrochlorination of poly(vinyl chloride) in solution and the effect of synthesis conditions on graft copolymerization with styrene

Dehydrochlorinated poly(vinyl chloride) PVC (DHPVC) was prepared in solution in the presence of bases with different basicity, such as sodium-n-butoxide and piperidine. Kinetics of PVC dehydrochlorination was studied under nitrogen atmosphere. The activation energies of 11.6 and 15 kJ/mol were obtained for reaction in the presence of sodium-n-butoxide and piperidine, respectively. Measurements of infrared (IR) spectroscopy, color intensity, GPC and DSC were used to indicate the changes in PVC structure and properties due to formation of conjugated polyene sequences in the polymer chain. A maximum of about 50 and 20% dehydrochlorination were obtained in the presence of sodium-n-butoxide and piperidine, respectively. Dehydrochlorinated poly(vinyl chloride)-g-polystyrene (DHPVC-g-PSt) was prepared by free radical mechanism using benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) as free radical initiators, under nitrogen atmosphere. The effect of synthesis conditions such as temperature, type of initiator, initiator concentration, and reaction time on PSt content of graft copolymer were investigated. PSt contents of graft copolymers were determined by gravimetry, elemental analysis, and IR spectroscopy. On the whole, a maximum of about 40 and 30 wt% PSt in the DHPVC-g-PSt graft were obtained by BPO and AIBN, respectively.