Kinetic and electron paramagnetic resonance studies on radical polymerization. Radical copolymerization of p-tert-butoxy-styrene and dibutyl fumarate in benzene

✍ Scribed by Tsuneyuki Sato; Sumio Shimooka; Makiko Seno; Hitoshi Tanaka

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 425 KB
• Volume: 195
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1994.021950302

✦ Synopsis

Abstract

The copolymerization of p‐tert‐butoxystyrene (1) (M~1~) and dibutyl fumarate (2) (M~2~) initiated with dimethyl 2,2′‐azobisisobutyrate (3) was studied in benzene at 60°C kinetically and by means of electron paramagnetic resonance (EPR) spectroscopy. The monomer reactivity ratios were determined to be r~1~ = 0,18 and r~2~ = 0,01, indicating that homopropagation of M~2~ is almost negligible in the copolymerization. The copolymerization system was revealed to involve EPR‐observable propagating polymer radicals under practical copolymerization conditions. The apparent rate constants of propagation (k~p~) and termination (k~t~) determined by EPR show a rapid increase in the range from 0,9 to 1,0 of feed composition (f~1~ = {[M~1~]/([M~1~] + [M~2~])}) of M~1~. From the relationship between k~p~ and f~1~ based on Fukuda's penultimate model, the rate constants of propagation of copolymerization were evaluated; k~111~ = 140 L · mol^−1^ · s^−1^, k~211~ = 4,3 L · mol^−1^ · s^−1^, k~112~ = 778 L · mol^−1^ · s^−1^, k~212~ = 24 L · mol^−1^ s^−1^ and k~121~ = 19 L · mol^−1^ · s^−1^, suggesting a pronounced penultimate effect.