The Synthesis Of New Hyperbranched Polymers And Applied Research

Hyperbranched polymer is a unique three-dimensional molecular structure of polymers with low viscosity, high reactivity, good compatibility, as well as a large number of end-group functionality can be further fine performance, and so on. Hyperbranched polymer modified epoxy used mainly has the following advantages:(1) Hyperbranched polymer spherical three-dimensional structure of the epoxy curing structures to reduce the rate of contraction; the activity of hyperbranched polymers can be end-group curing reaction directly involved in the formation of three-dimensional network structure, a large number of terminal functional groups can speed up the curing speed; (2) Hyperbranched polymer structure size and spherical in the other to eliminate the system of traditional toughening observed the harmful effects of particulate trap, play a role in toughening. These unique features allow the hyperbranched polymer become an important direction of scientific research.In this paper, the monomer N, N-diethoxyl-3-amino ethyl propionate (AB2) was synthesized by Micheal addition of ethanolamine and ethyl acrylate. The 1-5 generations of hyperbranched poly (amine-ester) with terminative hydroxyl group were synthesized respectively by pseudo-one-step manner, with pentaerythritol as core molecules and AB2 as the monomer, then the terminal hydroxyl groups were modified by its reaction with epichlorohydrin to give a new hyperbranched poly (amine-ester) with terminative epoxy group. The properties of hyperbranched poly (amine-ester) with terminative epoxy group were investigated by FT-IR,GC-MS,Viscosity,GPC,hydroxyl value and end value of the determination of epoxy and chemical analysis. The results showed that its viscosity was 30-554mPa.s and that is lower than the linear molecules, with the same molecular weight.and the every generation of hyperbranched poly (amine-ester) with terminative epoxy group have a higher epoxy value,0.288～0.512 mol/100g, the monomers gradually was higher and the relative molecular mass distribution was narrower.We have also examined the mechanical, thermal properties of 3～5 generation on behalf of the epoxy-terminated hyperbranched poly (amine - ester)-modified epoxy resin cured, the results showed that epoxy-terminated hyperbranched poly (amine - ester) increased the impact strength of composite materials to improve the material toughness. When the third-generation of epoxy-terminated hyperbranched poly (amine - ester) is added the amount of 7%, in the curing system, the impact strength were increased by 96.79%, the tensile strength increased by 12.01%. From the scanning electron micrographs, It can be seen that the compatibility between the epoxy-terminated hyperbranched poly (amine - ester) and epoxy resin is very good, cured epoxy-terminated hyperbranched poly (amine - ester) in the loop epoxy resin matrix were well dispersed, and the cross-section shows "Sea - Island" structural features. Epoxy-terminated hyperbranched poly (amine -ester) were dispersed in the epoxy matrix by the form of micron dispersed phase (micro-dispersed phase). When the material is subject to external loads, micro-dispersed phase will bear the load to increased its mechanical properties. However, The adding of the epoxy-terminated hyperbranched poly (amine - ester) has a definite impact on the thermal properties of the epoxy resin composite materials, making the thermal decomposition temperature droped by about 15～20℃and the glass transition temperature decreased by about 7～10℃.