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

In this work we report the synthesis of poly(hydroxyethyl-methacrylategraft- polycaprolactone)-block-poly(caprolactone) copolymers, P(HEMA-g-PCL)-bPCL, by combining ring-opening polymerization (ROP) and reversible additionfragmentation chain-transfer polymerization (RAFT). The successful synthesis of the targeted "comb-like" block copolymers obtained was confirmed by 1 H-Nuclear Magnetic Resonance, Fourier Transform Infrared Spectroscopy and Size Exclusion Chromatography. Thermal behavior of the copolymers was studied by Differential Scanning Calorimetry, and their thermal stability was investigated by modulated thermogravimetric analysis. In this sense, the "comb-like" block copolymers exhibited controlled molar masses between 6,000 g/mol and 45,000 g/mol, and polydispersity indexes lower than 1.3. Besides, thermal analysis evidenced a noticeable reduction in the melting temperature compared with linear PCL homopolymer, as well as, in the activation energy for the degradation process.