Photoinitiated copolymerization of citronellol and methylmethacrylate

Abstract

Free radical copolymerization of citronellol and methyl-methacyrlate (MMA) in xylene at 30±0.2°C using benzoylperoxide (BPO) as the photoinitiator for 21 h has been carried out. The system follows non-ideal kinetics (<i>R</i>_pα[BPO]^0.62 [citronellol]^0.87 [MMA]^0.90) due to both primary radical termination and degradative chain transfer reaction. Analysis of the copolymer by IR and NMR shows the presence of alcoholic and acrylate group in the copolymer. The glass transition temperature of copolymer, calculated by differential scanning calorimetry (DSC) is 80°C. The nearly alternating nature of the copolymer is confirmed by the product of reactivity ratios <i>r</i>_t (MMA)=0.062 and <i>r</i>₂ (citronellol)=0.005, calculated by Kelen-Tudos method. The Alfrey-Price, Q-e parameters for citronellol have been calculated as -1.09 and 1.47. The mechanism has also been explained.