Synthesis And Characterization Of Hyperbranched Polyesters With Pyromellit-Tetra-Diethanol Amine As The Central Core

Hyperbranched polymers (HBP) are a kind of highly branched macromolecules with three-dimensional topological structures. Compared with the traditional linear polymers, as their unique physical and chemical properties, HBP have a lot of advantages such as good solubility, high rheologibility, low solution and melt viscosity, a large amount of terminal groups, many inner cavities. People have paid considerable attention on HBP, in the recent decades, remarkable development has been made on their synthesis, characterization and modification. This leads to an increasing interest on the application of hyperbranched polymers, such as in the fields of coating, the molecular self-assembly, surface modification, the control-release of medicine, gene transfection, nanoparticle encapsulation, and so on. The paper chooses the synthesis of hyperbranched polymers as the major of this master dissertation for the importance of its theoretical research and practical application. The pyromellit-tetra-diethanol amine (By) was synthesized. Water-solubility hyperbranched polyamido-ester (HBPE) was prepared by pseudo-one-pot procedure using 2,2-bis(hydroxymethyl)-propionic acid (DMPA) as AB2 monomer and By as central core. Moreover the effects of synthesis conditions on the structure of HBPE were also investigated.Pyromellit-tetra-diethanol amine (By) was prepared by using pyromellitic dianhydride (PMDA) and diethanol amine (DEA) as raw materials, the influences of synthesising conditions:ratio of DEA and PMDA, reaction temperature, reaction time and concentration on the structure and properties of By were investigated. FT-IR spectroscopy,1H-NMR spectroscopy, chemical titration, viscosity measurement and gel permeation chromatography (GPC) were employed to characterize the samples. The results showed that the optimum conditions were determined as following:temperature was room temperature, reaction time was 3 hours and the ration of DEA and PMDA was 4.4:1. The number average molecular weight (Mn) and weight average molecular weight (Mw) of By was 1683 g·mol-1 and 1911 g·mol-1 respectively. The polydispersity (Mw/Mn), hydroxyl value, and intrinsic viscosity ([ηinh]) of By was 1.14,820.32 mg KOH·g-1 and 0.0676 dL·g-1, respectively.The first generation of hyperbranched polyamido-ester (1G-HBPE) was prepared by using dimethylolpropionic acid (DMPA) as AB2 monomer and By as central core, the influences of synthesising conditions:kind of catalyses and catalyzers dosage, reaction temperature, reaction time and polymerization methods on the structure and properties of 1G-HBPE were investigated. FT-IR spectroscopy,13C-CP/MAS-NMR spectroscopy, chemical titration, viscosity measurement and GPC were employed to characterize the samples. The results showed that the optimum conditions were determined as following:catalyzer was p- toluenesulfonic acid(p-TSA), catalyzer dosage was 2.00wt%, temperature was 150℃, reaction time was 7 hours, by melt polycondensation. Mn and Mw of 1G-HBPE was 2195 g·mol-1 and 3676 g·mol-1, respectively. Mw/Mn, [ηinh]and degree of branching(DB) of 1G-HBPE was 1.67, 0.0820 dL·g-1 and 0.47, respectively.The second generation of hyperbranched polyamido-ester (2G-HBPE) was prepared at 150℃by melt polycondensation by using 2,2-bis(hydroxymethyl)-propionic acid (DMPA) as AB2 monomer, p-toluenesulfonic acid(p-TSA) as catalyzer and By as central core, the influences of synthesising conditions:feeding style and reaction time, on the structure and properties of 2G-HBPE were investigated. FT-IR spectroscopy, chemical titration, viscosity measurement and GPC were employed to characterize the samples. The results showed that the optimum conditions were determined as following:feeding style was pseudo-one-pot procedure, reaction time was 9 hours. Mn and Mw of 2G-HBPE was 3750 g·mol-1 and 4904 g·mol-1, respectively. Mw/Mn and [ηinh] of 2G-HBPE was 1.31 and 0.0861 dL·g-1 respectively.HBPE have good solubility in polar solvent such as DMF, DMAC, DMSO, methanol and water and can slightly soluble in ethanol and acetone. Horeover in some low-polar and non-polar solvent such as diethyl ether, chloroform, normal hexane, toluene, THF, dichloromethane, HBPE can not soluble in them.