Synthesis And Characterization Of Responsive Hyperbranched Polyesteramide Multi-arm Star Copolymers

Hyperbranched polymers (HBP) are a class of highly branched, a large amount of terminal groups spherical macromolecules. In recent years, HBP are popular due to its structure, physical and chemical properties, especially in the field of drug controlled and released. The characteristics of many inner cavities, low solution and melt viseosity can be used to load and drug delivery effectively.If the stimuli-sensitivity properties macromolecule segmers are grafted to the suface of the HBP so that they can be used as an ideal material of drug camer and controlled release.According to the amount of substance ratio 1:1 reaction, monomer (AB2) was prepared by using cheap succinic anhydride(SA) and diethanolamine(DEA) as raw materials. Hydrophilic hyperbranched polyesteramide(HBPEA) was prepared in solution polymerization under p-toluene sulfonic acid as catalyst. The influences of synthesizing conditions: such as the reaction time, reaction temperature, the dosage of catalyst and water-carrying agent on the structure and properties. The results showed that the optimum condition were determined as following: reaction time was 1 hour, temperature was 0℃, the amount of catalyst was 4%, water-carrying agent was methylbenzene and extracting agent was acetone and ethyl ether mixed(1:1). The structures were characterized by FT-IR,1H NMR and UV.HBPEA-Br was prepared by using HBPEA and 2-bromopropionyl bromide, the synthesizing conditions:drop temperature and reaction time at room temperature were studied. The results showed that drop temperature was 0℃ and reaction time under room temperature was 72 hours. Using ATRP, HBPEA-star-PDMAEMA(P1-P5) was prepared by macroinitiator(HBPEA-Br), monomer(DMAEMA), CuBr/PMDETA as catalyst. The structures and morphology were characterized by FT-IR,1H NMR, TG, TEM and DLS. Thermo-and pH responsive properties were characterized by variable temperature UV-vis spectrometry.Using the dialysis method, drug complexes(P4/HCPT) was prepared by HBPEA-star-PDMAEMA(P4) and 10-hydroxycamptothecine(HCPT). The results showed that HBPEA-star-PDMAEMA with different arm length can load HCPT effectively, the range of drug loading efficiency and entrapment efficiency was 1%-5% and 6%-17%, respectively. That drug release in vitro was characterized by UV proved that drug delivery(P4) under high temperature (relatively body temperature) and slightly acidic conditions has certain application prospect.