80037-92-9Relevant academic research and scientific papers
Initiation mechanisms for radical polymerization of methyl methacrylate with tert-butyl peroxypivalate
Nakamura, Tomoyuki,Busfield, W. Ken,Jenkins, Ian D.,Rizzardo, Ezio,Thang, San H.,Suyama, Shuji
, p. 10824 - 10828 (1996)
The reaction of tert-butyl peroxypivalate (2) with methyl methacrylate (3) has been studied by the radical trapping technique employing 1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindol-2-yloxyl (1) as a scavenger. Thermolysis of 2 generated tert-butoxyl, tert-butyl, and methyl radicals in the ratios of 48:50:2 at 60 °C in 3. Both alkyl radicals underwent selective tail addition to 3. tert-Butyl radicals reacted about twice as fast as methyl radicals with 3. The absolute rate constant for addition of tert-butyl radicals to 3 was estimated to be 2.3 x 106 M-1 s-1 at 60 °C. The overall ratio of addition to H abstraction in the reaction of 2 with 3 was 5:1.
Free radical initiation mechanisms in the polymerization of methyl methacrylate and styrene with 1,1,3,3-tetramethylbutyl peroxypivalate: Addition of neopentyl radicals
Nakamura, Tomoyuki,Busfield, W. Ken,Jenkins, Ian D.,Rizzardo, Ezio,Thang, San H.,Suyama, Shuji
, p. 10987 - 10991 (1997)
The reactions of 1,1,3,3-tetramethylbutyl (tert-octyl) peroxypivalate (1) with methyl methacrylate (MMA) and styrene in the presence of the free radical scavenger 1,1,3,3-tetramethyl-2,3-dihydro-1H-isoindol-2-yloxyl (2) have been studied at 60°C. tert-Butyl and tert-octyloxyl radicals (3) were generated from the thermolysis of 1. The predominant unimolecular reactions of 3, that is, β-scission to form neopentyl radicals (14b) and a 1,5-H shift to form 4-hydroxy-2,2,4-trimethylpentyl radicals (14c), were observed in both monomer systems. The resulting alkyl radicals underwent selective addition to the two monomers. The relative reactivities of the alkyl radicals toward addition to the monomers were obtained from competitive addition/trapping reactions. The absolute rate constants for the addition of alkyl radicals 14b and 14e to the two monomers at 60°C were estimated to be 9.5 x 105 and 2.6 x 105 M-1 s-1 to MMA and 4.5 x 105 and 0.7 x 105 M-1 s-1 to styrene, respectively. The low reactivities of 3 and 14e toward addition to MMA and styrene were attributed to steric effects. Steric effects were also responsible for the low rate of the 1,5-H shift in 3.
Initiation Mechanisms in Radical Polymerizations: Reaction of Cumyloxy Radicals with Methyl Methacrylate and Styrene
Rizzardo, Ezio,Serelis, Algirdas K.,Solomon, David H.
, p. 2013 - 2024 (2007/10/02)
Cumyloxy (1-methyl-1-phenylethoxy) radicals have been generated by thermolysis (60 deg C) of dicumyl hyponitrite in methyl methacrylate and styrene.The carbon-centred radicals formed by interaction of cumyloxyl with the respective monomers were trapped as stable adducts of 1,1,3,3-tetramethylisoindolin-2-yloxyl.Extensive hydrogen atom abstraction and methyl radical generation as well as double-bond addition were observed in methyl methacrylate.Styrene underwent only double-bond addition by both cumyloxy and methyl radicals.Some possible implications of these results for polymer structure are discussed.A kinetic study of the decomposition of dicumyl hyponitrite in cyclohexane at various temperatures gave k=7.7*1014exp(-13600/T) s-1 for the rate constant.Rate constants for the addition of cumyloxyl to methyl methacrylate (k ca.2*104 dm3mol-1s-1) and styrene (k ca. 2*105dm3mol-1s-1) at 60 deg C have been estimated
