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_pαBPO]^0.5Sty]^1.0MMA]^1.0Lim]^?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 C? H stretching of phenyl (? C₆H₅) protons of Sty, ? OCH₃ of MMA, and trisubstituted olefinic protons of Lim, respectively. The ¹H‐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 r₁ (MMA; 0.33) and r₂ (Sty + Lim; 0.06) were calculated with the Kelen–T?udos method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2343–2347, 2004