Synthesis,Characterization And Properties Of Polyamidoamine Compounds Based On P-Phenylenediamine

Dendritic polymers are a kind of macromolecules with hyperbranched molecular structure with a large number of terminal functional groups,and possess many excellent features that the traditional linear polymers don’t have,such as low viscosity,high solubility and good rheological property.Because of these merits,dendrimers and hyperbranched polymers have attracted extensive attentions and broad applications in polymer research fields.A series of different types of dendritic polymers has been successfully synthesized by researchers through exploring the type of monomers,synthetic approaches and modification methods.Among these types,polyamide dendritic polymers are the ones which have been most widely studied and used in industrialized applications.Particularly,dendritic polyamides possessing aromatic structures have better heat resistance and mechanical properties than the aliphatic analogues.Furthermore,they have remarkable fluorescence effect and vector ability for small organic molecules.In this thesis,the synthesis,structure and properties of polyamidoamine dendrimers and hyperbranched polyamides are briefly overviewed.In addition,research progress of polyamidoamine dendrimers containing aromatic structure and aromatic hyperbranched polyamides is summarized.In order to meet the requirements of different cases,dendritic polymers that show various performances can be achieved by choosing different core units,branched units and terminal functional groups.Herein,three different types of polyamidoamine compounds based on p-phenylenediamine were prepared.The polyamidoamine dendrimer with p-phenylenediamine core was synthesized through a divergent approach with successive Michael addition reaction and amidation reaction.The aromatic hyperbranched polyamidoamine was prepared using G0.5 p-phenylenediamine-core dendrimer with ester end groups and ethylenediamine as the raw materials through a combination technique of melt polymerization and solution polymerization.Both polyamidoamine dendrimers and hyperbranched polyamidoamine were characterized by FT-IR and1H-NMR spectra and the results demonstrate that the polymer structure obtained.The fluorescent properties of hyperbranched polyamidoamine compounds were also studied.In addition,cross-linked polyamidoamine polymers were also prepared using G0.5 p-phenylenediamine-coredendrimer and ethylenediamine as monomers by employing a melt polymerization process.The structure of cross-linked polymers was characterized by FT-IR spectra.Their thermal performance was recorded in a TG analysis and their compressive strength was determined.The results show that the cross-linked polyamidoamine polymers can exhibit a good thermal stability and a considerable compressive strength by controlling the reaction conditions.Besides,the solubility enhancing effect of the aromatic hyperbranched polyamidoamine compounds was investigated,using ibuprofen as a model drug molecule.Aliphatic hyperbranched polyamidoamine analogues and ethylenediamine were employed as reference compounds to study the mechanism of the solubility enhancing effect of the hyperbranched polymers.The interaction between the hyperbranched polymers and ibuprofen molecules was studied by FT-IR and fluorescence techniques.The results show that the aromatic hyperbranched polyamidoamine can significantly improve the aqueous solubility of ibuprofen,which increases with the concentration of hyperbranched polymers.Compared with the reference compounds,hyperbranched polyamidoamine with aromatic structure are deduced to improve the dissolution of ibuprofen mainly through the electrostatic interactions related to the end amine groups and the encapsulation effect of the internal cavities.