Thermally Induced Aerobic Autopolymerization of Methyl Methacrylate in Amide-Type Solvents: Simultaneous Polymerization during Induction via Direct In Situ O2 Activation.

Autor: Liu, Xiang, Zhai, Guangqun
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Zdroj: Macromolecular Chemistry & Physics; Jun2015, Vol. 216 Issue 11, p1201-1211, 11p
Abstrakt: The thermally induced spontaneously initiated autopolymerization of methyl methacrylate (MMA) upon air exposure in amide-type polar solvents at 75-90 °C is unexpectedly observed and then investigated. By using iodometric analysis, it is confirmed that oligo(MMA peroxide)s in situ form at a moderate rate via thermally induced interpolymerization of MMA with O2 diffusing from air above 70 °C and give rise to an equivalent concentration above 10−4 mol L−1 in 2-4 h in N, N-dimethylacetamide, N, N-dimethylformamide, and N-methyl-2-pyrrolidinone (in a descending order of the formation rate). Simultaneously, oligo(MMA peroxide) undergoes thermally induced homolytic decomposition into alkyloxyl radicals to initiate polymerization of MMA in the above solvents at a rate comparable to those initiated by chemical initiators. Thus, the thermally induced in situ O2 activation into peroxides via interpolymerization accounts for the spontaneous initiation of the autopolymerization of MMA in these solvents at moderate temperature. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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