Synthesis and characterization of star-brush copolymer by RAFT bulk polymerization using "grafting from" method

In this study, the star-brush copolymer was prepared by reversible addition/fragmentation chain transfer (RAFT) bulk polymerization in the presence of multifunctional macro-RAFT agent based on poly(ɛ-caprolactone) (PCL) using the "grafting from" method. For this purpose, multifunctional macro-RAFT agent based on PCL was synthesized from the reaction of the brominated/chlorine-terminated poly(ɛ-caprolactone) (PCL-Br/Cl) and ethylxanthic acid potassium salt. Then, the poly(ԑ-caprolactone-g-styrene) [(PCL-g-PSt)] star-brush copolymer was synthesized via RAFT bulk polymerization using multifunctional macro-RAFT agent based on PCL. This polymerization was carried out at 80 oC by changing the polymerization time and, both the polymerization time and the polymerization temperature were investigated on the molecular weight, monomer conversion and dispersity. As a result of this polymerization, very high molecular weight copolymer with low dispersity was obtained. The products were characterized by using multi-instruments such as proton nuclear magnetic resonance spectroscopy, Infrared spectroscopy, gel permeation chromatography, thermo gravimetric analysis and differential scanning calorimetry.