Effects of end-groups on properties of hyperbranched polyether

In order to investigate influence of end-groups on thermodynamic property and viscosity of hyperbranched polyether. Three series of hyperbranched polyethers with three different end-groups were studied. These three groups are: hydroxyl, acetate and stearic acid ester. The result confirms the complicated effect of end-groups on properties of hyperbranched polymer. When end-groups change from polar groups of hydroxyl to non-polar groups of acetate, glass transition temperature reduced about 50°C, viscosity reduced sharply too. Glass transition temperature and viscosity all increase with generation rise. When end-groups change from acetate to stearic acid ester, corresponding hyperbranched polyether change from amorphous to crystalline. The crystallization stemmed from long chain structure of end-group, which is easy to form crystalline, its crystalline region molten become main thermodynamic transformation, and obscure the glass transition.