Kinetic Studies on the Radical Polymerization of Butadiene Derivatives

Abstract

A kinetic study on the radical polymerization of diene compounds was carried out at 25±0.00loC. The diene compounds were ethyl pentadienoate and its derivatives CH2 =CX-CH=CHCOOCH 2 CH 3 (EP:X=H, EMP:X=CH 3 , and EEP:X=OCH3), and 1acetoxybutadiene (AB). Elementary rate constants of these diene compounds were determined by the rotating sector method; the values of kP and k, for EP, EMP, EEP, and AB were 30.9 and 1.9x 10 7 , 29.7 and 2.3x 10 7 , 9.9 and 0.93x 10 7 , and 18.0 and 28.1 x 10 7 M-1 s-1 , respectively. These kP values are lower than those reported for styrene, MMA, methyl acrylate, and vinyl acetate. Cross-propagation rate constants (k 12 and k 21) were estimated from the kP values and monomer reactivity ratios in the copolymerizations of these dienes (M2) with styrene (M.). Reactivity of the monomers and the propagating radicals was compared with vinyl compounds and other dienes by using k 12 and k21 , respectively. Lower kP values of these dienes are primarily ascribed to the fact that the decrease in the reactivity of the propagating radical is larger than the increase in that of monomer. Change in radical reactivity among dienes is larger than that in their monomer reactivity. Effects of the resonance stabilization of the propagating radicals on k, were not clearly evident in these radical polymerizations which are discussed oh the basis of the preexponential factor.

Stereospecific Polymerization of Dialkyl Muconates through Free Radical Polymerization: Isotropic Polymerization and Topochemical Polymerization

“…Stereospecific Polymerization of Substituted Butadienes. The trans -1,4-polymerizations through radical polymerization in isotropic media have also been reported for several other butadiene derivatives, for example, 2,4-pentadienoic acid and its esters − and 2,4-hexadienoates (alkyl sorbates) . The preferred trans -1,4-propagation of these diene monomers is accounted for by similar conformations of the propagating radicals depicted in Chart , where X is CO 2 R, CH 3 , or H. Thus the stereoselectivity is determined by the conformation of the propagating chain end during the free radical polymerization of the muconates and other related substituted butadienes.…”

ESR Study on Radical Polymerizations of Diene Compounds. Determination of Propagation Rate Constants

“…More than 10 years ago, Kamachi et al performed a kinetic study on the radical polymerization of diene compounds and attempted ESR measurements of the polymerization system to obtain additional information on the propagating radicals . Since no signal could be detected in these polymerizations in the liquid state at room temperature, ESR measurements were performed on frozen solutions.…”

“…In 1992, Yamada et al found that an application of a computer to the ESR measurements led to higher sensitivity on ESR observation and that well-resolved ESR spectra of propagating radicals of styrene and substituted styrenes were observed at room temperature. 3 More than 10 years ago, Kamachi et al performed a kinetic study on the radical polymerization of diene compounds 4 and attempted ESR measurements of the polymerization system to obtain additional information on the propagating radicals. 5 Since no signal could be detected in these polymerizations in the liquid state at room temperature, ESR measurements were performed on frozen solutions.…”

Functional Monomers and Polymers CLXVII. Asymmetric Inclusion Polymerization of 1-Alkyl-1,3-butadienes in Deoxycholic Acid and Apocholic Acid Canals by Long-Lived Propagating Radicals

“…This is probably because the reactivity of the diene monomers with free radicals is higher than that of vinyl monomers. 15 Thus, we succeeded in preparing the optically active polymers of 1-alkyl-BD monomers by long-lived propagating radicals through the inclusion polymerization using DCA and ACA as the chiral hosts. Until now, there are only two reports on asymmetric polymerization of diene monomers via radical mechanism by use of an optically active ester of pentadienoic acid 16 and perhydrotriphenylene inclusion compounds.…”