Phase transfer catalysis: Effect of cationic surfactants on the free radical polymerization of methylmethacrylate

摘要

The effect of cationic surfactants, decyltrimethylammonium bromide (DTAB), dodecyltrimethylammonium bromide (DDTAB) and tetradecyltrimethylammonium bromide (TDTAB), has been studied as phase transfer catalysts (PTCs) on the free radical polymerization of methylmethacrylate (MMA) using potassium peroxydisulfate (PDS, Ksub2/subSsub2/subOsub8/sub) in toluene-water biphase system. Of the three PTCs in their respective critical micellar concentration (CMC) and in common concentration, the TDTAB show comparatively high rate of polymerization (Rp), 7.76 × 10sup-5 /supmol.Lsup-1/sup.Ssup-1/sup, at the lowest reaction time of 30 min in its concentration of 2 × 10sup-2 /supmol.Lsup-1/sup. Detailed kinetic study of?polymerization of MMA has been carried out using TDTAB at a fixed time of 30 min by varying [MMA], [Ksub2/subSsub2/subOsub8/sub], [TDTAB] and temperature. Based on the kinetic results, the free energy of activation has been calculated, and a suitable mechanism and rate law has been proposed.