Study of the nature of radical polymerization of methyl methacrylate with “aged” chromium(II) acetate/benzoyl peroxide

Abstract

The polymerization of methyl methacrylate (MMA) in DMF with "aged" chromium(I1) acetate (Cr(Ac3) and benzoyl peroxide (BPO), previously formulated as a living radical polymerization, was investigated. The reaction between Cr(Ac)2 and BPO gives besides N-methyl formamidomethyl benzoate (3) the N-methylformamidomethylchromium(III) cation (6) as intermediate, which itself may react with BPO with the formation of additional free radicals as compared with the thermolysis of BPO. Thus, the polymerization of MMA in this system could be shown to be a normal radical one with free and uncomplexed radicals. The increase of the degree of polymerization with aging and monomer conversion is explained by the decreasing rate of the radical forming reactions and the onset of the gel effect.

Synthesis, Physicochemical Characterization, and Applications of Polyurethane Ionomers: A Review

“…Hence, if the molecular weight of the polymer increased with increasing conversion, then the system follows "living" radical polymerization. Using this evidence, a number of polymerizations [95,97,98,100,102,119,122,126,129,[131][132][133][135][136][137][138] have been proven to be following a "living" radical mechanism.…”

“…"Aged" chromium acetate-benzoyl peroxide system [125][126][127][128][129][130] and triisobutylaluminum-2,2'-bipyridyl-2,2,6,6-tetramethyl-1 -piperidinyloxy (TEMPO) system [131][132][133][134] are examples of "living" radical polymerization through persistent radicals. "Living" radical polymerization through alkyl halides [101] is an example of a degenerative transfer agent [135][136][137][138].…”

Metal complexes in controlled radical polymerization

“…The latter was stabilized by complexation to become a long-lived radical (Eq. However, it was also proposed that the above system was indeed a conventional radical polymerization with the gel effect [44]. The propagation step was assumed to proceed via "insertion" of monomer into the benzoyloxy radical-Cr"' complex (Eq.…”

A Kinetic and Heat Balance Model for Anionic Batch Block Copolymerization of Styrene and Isoprene

“…k t [27] 3.92 Á 10 3 s -1 8.70 Á 10 3 3.26 Á 10 -6 s -1 speeds were chosen to investigate if the model is sensitive to the small changes in heat transfer properties introduced by the different flow rates. Predici calculates the heat capacity of the reaction mixture from the individual specific heat capacity values.…”