Synthesis of Poly(Glycidyl Methacrylate) through Reversible Addition-Fragmentation Chain Transfer (RAFT) Polymerization

Abstract

Synthesis of poly(glycidyl methacrylate) (PGMA) from glycidyl methacrylate (GMA) monomer was successfully carried out through reversible addition-fragmentation chain transfer (RAFT) polymerization technique using a RAFT agent 4-Cyano-4-(thiobenzoylthio)pentanoic acid (CPADB) and initiator 4,4’-Azobis(4-cyanopentanoic acid) (ACPA) with mole ratio of 100:1:0.15 for GMA:CPADB:ACPA and temperature of 60 ºC.  Synthesis of PGMA was first started with 6 hours of RAFT polymerization. However, since it was unsuccessful, the study was continued to study the optimum time of PGMA polymerization through RAFT polymerization by manipulating the reaction time whereas the mole ratio of GMA:ACPA:CPADB with temperature of reaction, 60 ºC was kept constant. The PGMA polymerization time of reaction was varied and studied for 8, 10, 14, 15, 16, 18 and 22 hours. As the time passed on, the intensity of the pink colour observed from the beginning of reaction decreased but the viscosity of the solution increased. The PGMA polymer was successfully synthesized and precipitated at the 14^th and 15^th hour. The percentage of conversion for 14 hours and 15 hours was 26% and 29% respectively. The PGMA crude was characterized using ¹H NMR.  NMR confirms PGMA was formed at 14 and 15 hours of polymerization reaction. Several PGMA peaks for below 14 hours polymerization reaction was missing while after 15 hours, there are present indicating PGMA was formed. However, after 15 hours, as the viscosity increases, the polymer formed gel. Gel formation causes no precipitation when the crude was added to methanol since it contains less PGMA.  The solid PGMA synthesized at 14 and 15 hours was characterized using FTIR-ATR and confirmed the presence of functional groups of PGMA polymer. In this study, PGMA was successfully synthesized at 14 to 15 hours of time via RAFT polymerization.