Kinetic and ESR Studies of Ring-Opening Radical Polymerization of 1,1-Bis(ethoxycarbonyl)-2-vinylcyclopropane

Abstract

Ring-opening radical polymerization of 1,1-bis(ethoxycarbonyl)-2-vinylcyclopropane (BEVCP) with dimethyl 2,2′-azobisisobutyrate (MAIB) was investigated kinetically in benzene. The overall activation energy (E a ) 94 ( 4 kJ/mol) was calculated from the polymerization rate (Rp) obtained at 30-60 °C. Rp (40 °C) is given by Rp ) k[MAIB] 0.6(0.1 [BEVCP] 1.0(0.1 , which is similar to that of conventional radical polymerizations involving bimolecular termination. The present polymerization system involves ESRobservable polymer radicals under the actual polymerization conditions. The total polymer radical concentration ([P • ]) was determined at different temperatures by ESR. Using Rp, [P • ], and the initiation rate obtained separately, the apparent rate constants of propagation (kp) and termination (kt) were estimated at different temperatures. The kp (71 L/mol‚s, 60 °C) and kt (5.8 × l0 4 L/mol‚s, 60 °C) values are much lower than those of typical vinyl monomers such as methyl methacrylate (MMA) and styrene. Owing to the markedly low kt, BEVCP is more homopolymerizable than MMA. Analysis of the observed ESR spectrum suggests that the present polymerization system involves ring-opened type and cyclobutyltype polymer radicals. This corresponds to the fact that the resulting poly(BEVCP) contains 1,5-adduct and cyclobutane structural units.

Determination of the Propagation Rate Coefficient of Vinyl Pivalate Based on EPR Quantification of the Propagating Radical Concentration

“…[31] More recently, the EPR method has been applied to further studies of the polymerizations of styrene, [37,38] acrylates, [39][40][41] methacrylates, [42][43][44][45][46][47] acryland methacrylamides, [48][49][50][51] a-substituted acrylates, [52,53] itaconate and related monomers, [54][55][56][57][58] as well as nonconjugated monomers. [59][60][61] Determination of k p by the EPR method and PLP-SEC has resulted in good agreement for styrene, [7,37] methyl methacrylate, [8,42] dodecyl methacrylate, [43,62] dimethyl itaconate, [22,63,64] and methyl a-(2-carbomethoxyethyl)…”

Synthesis and radical ring‐opening polymerization of vinylcyclopropanes derived from amino acids with hydrophobic moieties

“…After 20 h, the solution was diluted with chloroform (5 mL) and added to diethyl ether (300 mL). The resulting white precipitates were collected by filtration with suction and dried under vacuum to obtain polymer 2a (101.1 mg, 67%): 1 According to the typical procedure, 1c was polymerized in toluene to obtain polymer 2c (285.6 mg, 53%): 1 H NMR (CDCl 3 ): d 7.46 (2H, brd, J 5 7.6 Hz, NH 3 2), 5.52 (2H, brs, CH@CH), 4.43 (2H, dd, J 5 5.2, 7.6 Hz, NACH 3 2), 3.73 (6H, brs, OCH 3 3 2), 2.55 (4H, brs, CH 2 ACH@CHACH 2 ), 2.20-2.12 (2H, m, CH(CH 3 ) 2 3 2), 0.90 (12H, t, J 5 6.0Hz, CH 3 According to the typical procedure, 1d was polymerized in toluene to obtain polymer 2d (259.3 mg, 45%): 1 H NMR (CDCl 3 ): d 7.32 (2H, br d, J 5 6.8 Hz, NH 3 2), 5.51 (2H, brs, CH@CH), 4.50 (2H, br t, J 5 6.8 Hz, NACH 3 2), 3.72 (6H, br s, OCH 3 3 2), 2.51 (4H, brs, CH 2 ACH@CHACH 2 ), 1.60 (6H, brs, CH 2 CH(CH 3 ) 2 3 2), 0.92 (12H, t, J 5 4.0Hz, CH 3 According to the typical procedure, 1e was polymerized in toluene to obtain polymer 2e (639.3 mg, 71%). 1…”

“…Vinylcyclopropane (VCP) derivatives have attracted considerable attention as cyclic monomers undergoing RROP. [1][2][3][4][5][6] Among various VCPs, 1,1-disubstituted ones have been investigated most extensively. Their RROPs give the corresponding polymers bearing CAC double bonds in the main chains, often accompanied by a side reaction giving cyclobutane rings (Scheme 1).…”

Synthesis Kinetics of Polymer / Copolymer Latexes via Radical Ring-Opening Emulsion Polymerization of Vinylcyclopropane

“…Until now radical emulsion copolymerization of ECVCP with vinyl monomers remained a challenge for the researchers and no detail report is available in the area. Meanwhile, it has been observed that unsaturated polymers obtained by emulsion copolymerization of dienes with methacrylates undergo cleavage to form telechelic oligomethacrylates [12,13] and have been found to be suitable as precursors in the synthesis of co-networks that will find applications in cell culture and tissue engineering [14]. Considering this, emulsion copolymerization of ECVCP with acrylate monomers may be interesting as the resulting copolymers are expected to have unsaturated cleavage points.…”