Investigation on Surface Modification of Hydroxyl Terminated Hyperbranched polymer with Saturated Fatty Acid and its influence on rheological behavior of an epoxy diacrylate oligomer

In this study, hyperbtanched polyester amid (H1500) with hydroxyl surface functional groups was end-capped with a saturated fatty acid. The molecular structure of the modified hyperbranched polymer was characterized with HNMR and FTIR spectroscopies and GPC analysis. Decrease of peak intensity of –OH groups in FTIR spectra proved substitution of these functional groups with saturation fatty acids. HNMR spectra also demonstrate substitution of hydroxyl groups with fatty acid chains. GPC results show the higher percent of modification in hyperbranched polymers with lower molecular weight. Thermal properties of modified hyperbranched polymer were investigated by DSC analysis. For characterized of surface modification effect on the interaction of these polymers, the effect of modified and unmodified hyperbranched polymer on the viscosity of epoxy diacrylate oligomer were investigated. The results show that the replacement of OH groups with fatty acid chains can decrease the strength of hydrogen bonding and cause lower viscosity