| Abstract: | The graft copolymerization of styrene onto chlorinated butyl rubber (Cl-IIR) with stannic chloride as cationic catalyst was studied in cyclohexane, and the rate of polymerization, per cent grafting and grafting efficiency were obtained. Polymerization was carried out in a sealed tube. The product was precipitated in methanol and dried. The increase in weight of Cl-IIR used was regarded as styrene conversion, and the increase in weight after extraction by boiling acetone as the weight of grafted styrene. Grafting was confirmed by fractional dissolution and infrared spectra. The rate of polymerization of styrene was proportional to concentrations of styrene, Cl-IIR and SnCl4. The per cent grafting increased with styrene and SnCl4 concentration, but was constant with Cl-IIR concentration. It also increased with time and with halogen content in the polymer. The addition of a polar solvent such as nitrobenzene greatly promoted the grafting reaction and the per cent grafting was 200%. |
