Synthesis and characterization of a terpolymer of limonene, styrene, and methyl methacrylate via a free‐radical route

The free‐radical terpolymerization of a monocyclic terpene, namely, limonene (Lim), with styrene (Sty) and methyl methacrylate (MMA) in xylene at 80 ± 0.1°C for 2 h, with benzoyl peroxide (BPO) as an initiator under an inert atmosphere of nitrogen was extensively studied. The kinetic expression was R p α[BPO] 0.5 [Sty] 1.0 [MMA] 1.0 [Lim] −1.0 , where R p is the rate of polymerization. The overall energy of activation was calculated as 26 kJ/mol. R p decreased as [Lim] increased. This was due to a penultimate unit effect. The Fourier transform infrared spectra of the terpolymer showed bands at 3025–3082, 1728, and 2851–2984 cm −1 due to CH stretching of phenyl (C 6 H 5 ) protons of Sty, OCH 3 of MMA, and trisubstituted olefinic protons of Lim, respectively. The 1 H‐NMR spectra showed peaks at 7.3–8.1, 3.9–4.4, and 5.0–5.5 δ due to the phenyl, methoxy, and trisubstituted olefinic protons of Sty, MMA and Lim, respectively. The values of the reactivity ratios r 1 (MMA; 0.33) and r 2 (Sty + Lim; 0.06) were calculated with the Kelen–T̈udos method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2343–2347, 2004