Syntheses And Characterizations Of Hyperbranched Poly (Ester-Amide)s

During the last 15 years, polymer chemists have introduced a new macromolecule, namely hyperbranched polymer, and developed different synthetic strategies, structure-property relationships, new reaction mechanisms and applications. The novel polymer retains many important features of perfectly branched dendrimer counterparts (i.e. high solubility, reduced viscosity and multiple end groups relative to their linear analogues). The preparation of dendrimer is generally tedious because of various protection, deprotection and purification steps. For hyperbranched polymers, one-step polycondensation can be used with ABx-type monomers.In this thesis, a series of AB3-type monomers were prepared from gallic acid and amino acid. Hyperbranched poly(ester-amide)s bearing terminal acetyl groups were obtained by melt polycondensation of these AB3-type monomers. The NMR spectra confirmed the structure of all monomers and polymers. Because of the amide bonds in the backbone and the acetyl groups in the linear and terminal units, the resulting polymers were promising to be biocompatible components.In this thesis, the hyperbranched poly(ester-amide)s with hydroxyl end-group were synthesized by direct condensation of diethanolamine (CB2-type). and a series of anhydride (AA'-type). Diethanolamine reacts with anhydride, generating an AB2-type intermediate. Furtherself-condensation of this AB2-type monomer leads to hyperbranched poly(ester-amide)s. These polymers were modified with benzoic acid. The structures of all polymers were characterized by NMR and FTIR.In this thesis, by gel permeation chromatography measurement (GPC), weight-average molecular weights of hyperbranched poly(ester-amide)s were obtained and the narrow molecular weight distributions were showed to be (1.10-1.53). The thermal properties of all polymers were investigated by DSC and TGA. These polymers have good solubility in DMSO, DMAc and DMF. Their solution showed low intrinsic viscosity (0.04-0.24).