Synthesis and microstructure-mechanical property relationships of segmented polyurethanes based on a PCL-PTHF-PCL block copolymer as soft segment

The goal of this work has been the synthesis of novel materials based on a biodegradable polycaprolactone-block-polytetrahydrofurane-block-polycaprolactone diol (PCL-b-PTHF-b-PCL). The segmented thermoplastic polyurethanes (STPU) have been synthesised in bulk without catalyst at different molar ratios and their characterization has been performed by different techniques. The physic-chemical interactions, responsible for the unique polyurethane properties, have been evaluated by total attenuated Fourier transform infrared spectroscopy (ATR-IR) in the amide I region using a Gaussian deconvolution technique and, on the other hand, atomic force microscopy (AFM) has been employed to determine the phase microstructures. The effect of increase the hard segment content (HS) has been discussed from the viewpoint of the miscibility of hard and soft segments, analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The influence of HS content on the microstructure-mechanical property relationships has also been investigated. Special attention has been focused on the wettability of the samples, measured through water contact angle measurements (WCA), to determine the tendency for biocompatibility of the samples. (C) 2009 Elsevier Ltd. All rights reserved.