Synthesis of Grafted Block Copolymers Based on ε-Caprolactone: Influence of Branches on Their Thermal Behavior

MARIO D. NINAGO; AUGUSTO G. O. DE FREITAS; VIVINA HANAZUMI; PAULO I. R. MURARO; VANESSA SCHMIDT; CRISTIANO GIACOMELLI; ANDRÉS E. CIOLINO; MARCELO A. VILLAR

MACROMOLECULAR CHEMISTRY AND PHYSICS

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2015

1022-1352

The comb-like copolymers are a special class of polymeric materials in which the combined effects of thermodynamic incompatibility of the polymer segments and the architectural constraints of the branched architecture are reflected. This article describes a one-pot, one step synthesis of poly(hydroxyethyl methacrylate-graft-polycaprolactone)-block-poly(caprolactone) copolymers, P(HEMA-g-PCL)-b-PCL, by reversible addition-fragmentation chain-transfer polymerization (RAFT) and ring-opening polymerization (ROP), using a macro chain transfer agent (mCTA) and a ROP initiator. The P(HEMA-g-PCL)-b-PCL copolymers obtained exhibit controlled molar masses and relative low polydispersity indexes. Besides the conventional physicochemical characterization, non-isothermal crystallization tests were performed and Ozawa´s and Friedman´s methodologies were employed in order to obtain kinetic and energetic parameters of interest. The results obtained indicate that the activation energy for the copolymers is less than the one obtained for the linear poly(caprolactone) precursor (LPCL), evidencing that the presence of branches reduces the crystallization rate.