| In this paper, the role of oxygen in methyl methacylate (MMA) bulk polymerization at high temperature was studied. The emphasis was on the copolymerization of MMA and oxygen and the bulk polymerization of MMA and styrene (St) initiated by poly methyl methacrylate peroxide (PMMAP). The poly methyl methacrylate (PMMA)-MMA solution viscosity was also investigated.The copolymerization of MMA and oxygen was conducted, firstly. The polymeric product was characterized by NMR, Raman, EL, DSC, etc. The effect of reaction conditions on the polymeric product was examined. Then, MMA and St bulk polymerization were proceeded with PMMAP as an initiator. In the end, the viscosity of polymeric system in MMA bulk polymerization was studied, and several viscosity models were proposed to estimate the dependence of the solution viscosity on the concentration, molecular weight, and temperature.The results showed that the autoxidation of MMA by a free radical mechanism gives two simultaneous reactions, a copolymerization of MMA with oxygen, and a direct cleavage of MMA to methyl pyruvate and formaldehyde. The two processes involve a common intermediate, a free radical ending in a MMA unit. The yield of polymeric peroxide, as well as the ratio of polymeric peroxide to methyl pyruvate, increases with oxygen pressure, and decreases with increasing temperature.At high concentration of PMMAP. Rp is not proportional to1/2power of initiator concentration. The considerable reduction in the initiator exponent indicates that the polymerization kinetics is complex. The value of PMMAP efficience as an initiator is low. Active polymer PMMAP-PMMA-PMMAP, as well as PMMAP-PS-PMMAP was prepared.The viscosity of polymeric system in MMA bulk polymerization was studied, and several viscosity models were proposed to estimate the dependence of the solution viscosity on the concentration, molecular weight, and temperature. |
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