Effect of PEG molecular mass and HEMA capping on the thermal, morphological, and hydrophilic properties of isocyanate-terminated polyurethane acrylate films

Abstract

The synthesis of isocyanate-terminated polyurethane prepolymers was carried out by reacting toluene diisocyanate (TDI) with an acrylic polyol, PEG-400, and PEG-1000, followed by capping the prepolymers with 2-hydroxyethyl methacrylate (HEMA) to produce polyurethane acrylates. The purpose of this study was to examine how different molecular masses of PEG and HEMA impact the thermal, morphological, and hydrophilic/hydrophobic properties of PUA films. The properties of the polyurethane acrylates were analyzed using various techniques, including DSC, FTIR, TGA, 1H NMR, SEM methods, and water contact angles and gloss tests. The results indicated that microphase separation morphology is prevalent within the PUA containing PEG-1000 and that the hydrophilicity of the PUA film is primarily influenced by the microphase separation behavior. The results revealed that the addition of PEG-400 improved the compatibility of hard and soft segments, leading to a shift toward phase mixing in the microphase separation behavior of PU acrylates. The microphase separation behavior was further studied using FTIR analysis of the C = O stretching vibration, with deconvolution performed using Origin software. The findings provide valuable insights into the structure-property relationships of PU acrylates, which can be utilized to optimize their performance for different applications.