Determination of reactivity ratios and kinetics of free radical copolymerization of linalool with styrene

Abstract

AbstractCopolymerization of acyclic monoterpenoid, namely linalool (LIN), with styrene (STY) initiated by benzoyl peroxide (BPO) p‐acetyl benzylidene triphenyl arsonium ylide (p‐ABTAY) in xylene separately at 80°C for 180 min under inert atmosphere of nitrogen was performed. The results give a nearly alternating copolymer as evidenced from reactivity ratios (r1 = 0.016, r2 = 0.057) w.r.t. BPO; (r1 = 0.017, r2 = 0.052) w.r.t. p‐ABTAY (i.e. r1 = 0.0165 ± 0.0005 and r2 = 0.0545 ± 0.0025 per initiator set) using Kelen–Tudos method. The FT‐IR spectrum shows a band at 3026 cm−1 due to the aromatic ring of polystyrene and an alcoholic band of linalool at 3408 cm−1. 1H‐NMR spectrum shows peaks at δ 7.0–7.7 ppm of OH protons and peaks at δ 7.5–8.0 ppm due to phenyl protons of styrene. The system follows ideal kinetics i.e. Rp ∝ [LIN]1.0[STY]1.0[BPO]0.5/[p‐ABTAY]0.5. The overall energy of activation in the temperature range 75–85°C is 77.0 kJ mol−1 and 90.0 kJ mol−1, respectively. The values for Mark–Houwink constants for the functional copolymer has been evaluated as a = 0.40 and K = 1.60 × 10−4 with the help of gel permeation chromatography (GPC). Alfrey–Price, Q and e parameters for linalool have been evaluated as Q2 = 0.80; e2 = 1.25 w.r.t. BPO and Q2 = 0.90; e2 = 1.54 w.r.t. p‐ABTAY. Thermal properties of copolymers were investigated by thermogravimetric analysis (TGA) techniques. Copyright © 2004 John Wiley & Sons, Ltd.