This is the first report on the study carried out on high‐pressure free‐radical initiated oxidative copolymerization of styrene (STY) with α‐methylstyrene (AMS) at various temperatures (45–65 °C) at constant pressure (100 psi) and then at various pressures (50–300 psi) keeping the temperature (50 °C) constant. The compositions of the copolyperoxides obtained from the 1H NMR spectra were utilized to determine the reactivity ratios of the monomers. The reactivity ratios indicate that STY forms an ideal copolyperoxide with AMS and the copolyperoxide is richer in AMS. The effect of temperature and oxygen pressure on the reactivity ratios of the monomers was studied. The rates of copolymerization (RP) were used to determine the overall activation energies (Ea) and activation volume (ΔV#) of copolymerization. The unusually higher values of the ΔV# may be due to the pressurizing fluid oxygen which itself is a reactant in the copolymerization, the side reactions, and the chain‐transfer reactions occurring during copolymerizations.
The Arrhenius plots for the rate of the copolymerization of STY‐AMS‐O2 system at 100 psi of oxygen pressure.
