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A kinetic model dC/dt=a+βC~(1/3)for suspension polymerization of vinyl chloride was developed.Kineticstudies on such polymerization were carried out in a stainless steel tube reactor in the presence of high-,medium-,or low-activity initiators at different concentrations,and at temperatures ranging from 50 to 62~C.Twenty-six sets of kinetic data were obtained under different conditions.According to these experimentalresults,the acceleration behavior of vinyl chloride polymerization was discussed in detail.It is proposed thatthe auto-acceleration effect is due to the decrease of the termination rate constnat in the polymer-rich phaseand to the increase of initiator concentration owing to volume contraction during polymerization with aninitiator of lower activity.All plots of dC/dt against C are nonlinear during the two-phase stage,while dC/dtversus C~(2/2)curves show much better linearity up to 60—70% conversion.The proposed model can beused to explain satisfactorily why the reaction order of initiators is between 0.5 and 1.0.
A kinetic model dC / dt = a + βC ~ (1/3) for suspension polymerization of vinyl chloride was developed. Preparation of such stainless steel tube reactors in the presence of high-, medium-, or low -activity initiators at different concentrations, and atothermal ranging from 50 to 62 ~ C. Twenty-six sets of kinetic data were obtained under different conditions. According to these experimental results, the acceleration behavior of vinyl chloride polymerization was discussed in detail. It is proposed that the auto-acceleration effect due due to the decrease of the termination rate constnat in the polymer-rich phase and to the increase of initiator concentration due to volume contraction during polymerization with an initiator of lower activity. All plots of dC / dt against C are nonlinear during the two-phase stage, while dC / dtversus C ~ (2/2) curves show much better linearity up to 60-70% conversion.The proposed model can be used to explain satisfactorily why the reaction order of initiators is between 0.5 and 1.0.