Effect of substituents on the radical copolymerization of ring-substituted trans-cinnamonitriles with vinyl monomers

✍ Scribed by Hitoshi Tanaka; Masakazu Sakaguchi; Yoshimasa Kikukawa; Tsuneyuki Sato; Tadatoshi Ota

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 434 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950617

✦ Synopsis

Abstract

Radical copolymerizations of ring‐substituted trans‐cinnamonitriles with olefins such as styrene and acrylonitrile were studied at 60°C. The copolymerization parameters of cinnamonitriles (M~1~) in the copolymerizations with styrene (M~2~) were determined to be r~1~ = 0,01 to 0,30, r~2~ = 0,45 to 4,25, Q~1~ = 0,06 to 0,70, and e~1~ = −0,52 to 1,35. The relative reactivity, log(1/r~2~), showed a tendency to increase with increasing Hammett constant σ and was higher in conjugated cinnamonitriles than in less conjugated nitriles. For p‐substituted cinnamonitriles, ρ and γ values in the equation of log(1/r~2~) = ρ · σ + γ · E~R~ were estimated to be 0,48 and 2,0, respectively, where E~R~ is a resonance constant. The relative reactivity was also increased with increasing ^13^C NMR chemical shift of the olefinic β‐carbon of cinnamonitriles and decreasing polarity of the solvents used. In addition, the relative reactivity towards a poly(acrylonitrile) radical is higher in cinnamonitrile than in cinnamic esters. The structure of the radical generated by the attack of the 2‐methyl‐2‐propyl radical at the cinnamonitrile was examined by means of electron paramagnetic resonance (EPR) spectroscopy.