Thermal Characterization of “Comb-Like” Block Copolymers Based on PCL Obtained by Combining ROP and RAFT Polymerizations

Abstract

In this work we report the synthesis of poly(hydroxyethylmethacrylate-graft-polycaprolactone)-block-poly(caprolactone) copolymers,P(HEMA-g-PCL)-b-PCL, by combining ring-opening polymerization (ROP)and reversible addition-fragmentation chain-transfer polymerization (RAFT).The successful synthesis of the targeted comb-like block copolymersobtained was confirmed by 1H-Nuclear Magnetic Resonance, FourierTransform Infrared Spectroscopy and Size Exclusion Chromatography.Thermal behavior of the copolymers was studied by Differential ScanningCalorimetry, and their thermal stability was investigated by modulatedthermogravimetric analysis. In this sense, the comb-like block copolymersexhibited controlled molar masses between 6,000 g/mol and 45,000 g/mol, andpolydispersity indexes lower than 1.3. Besides, thermal analysis evidenced anoticeable reduction in the melting temperature compared with linear PCLhomopolymer, as well as, in the activation energy for the degradation process.