Polyurethane based on PLA and PCL incorporated with catechin: Structural, thermal and mechanical characterization

Catechin (Cat) was added into polyurethane (PU) based on a tri-block copolymer of poly(L-lactic acid) and poly(ε-caprolactone) (PLLA-b-PCL-b-PLLA) to improve the thermal stability of the final PU composite materials. The morphological, structural, mechanical and thermal properties of PU-Cat composites loaded with 1 wt%, 3 wt% and 5 wt% of Cat were investigated and designed as PU-Cat1, PU-Cat3 and PU-Cat5, respectively. Homogeneous films were obtained after the solvent casting process, but the higher amount of 5 wt% used in this work could not be successfully dispersed and produced some structural defects as were observed by scanning electron microscopy. Well dispersed Cat in PU-Cat1 and PU-Cat3 not only substantially improved the thermal stability due to the Cat antioxidant effect, but also allowed the crystallization of PCL and PLLA blocks in the final PU-Cat composites. Additionally, PU-Cat composite materials showed excellent stretchability for film production.Authors thank Spanish Ministry of Economy and Competitiveness, MINECO, (MAT2013-48059-C2-1-R and MAT2014-55778- REDT) and Regional Government of Madrid (S2013/MIT-2862) for the financial support. M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINECO, respectivelyPeer Reviewe