Synthesis And Characterization Of Copolymer Of Amino Acid And Isobutylene

In this thesis, two methods were proposed and investigated to synthesize the copolymer of amino acid and isobutylene.The first method was that NCA ring opening polymerization was carried on initiated by polyisobutylene with diphenylamine end group as macroinitiator, and AB/A2B block copolymers with glutamic acid block and PIB block were synthesized with Mn of 2700 g/mol and Mw/Mn of 1.10.In this method, arylamino terminated PIB was synthesized by direct combination of the carbocationic polymerization isobutylene (IB) with H2O/TiCl4/DMA initiating system with successive alkylation by further addition of arylamine solution in CH2Cl2, and the alkylation reaction conditions such as temperature, solvent polarity, arylamine concentration and reaction time were investigated. The experimental results indicated that the alkylation efficiency of diphenylamine commonly was higher than that of aniline, and 80% alkylation efficiency of polyisobutylene with diphenylamine could be obtained at the optimal conditions. Furthermore, AB block or A2B tri-arm star copolymer of isobutylene and y-benzyl-L-glutamate, could be synthesized via the manipulation of the monoalkylation and dialkylation in the macroinitiator diphenylamine terminated polyisobutylene.The second path was improvement to take the alkylation of benzyl alcohol with PIB in order to graft PIB with terminal group of chlorine atom or a-double bond onto the para-benzene ring. Then, the esterification of benzyl alcohol with PIB graft and glutamic acid was widely investigated. Finally, the thermal polycondensation of amino acid monomer grafted with PIB was carried on to produce a comb-shape copolymer PBLG-g-PIB with Mn of 18900 g/mol and Mw/Mn of 5.50.The problem that poly(phenylene methylene) would be synthesis via the homopolymerization of benzyl alcohol in this reaction, was resolved by optimizing the alkylation conditions, including the molar ratio of PIB to benzene alcohol, the concentration of catalyst TiCl4, the reactant concentration, the solvent and the reaction temperature. Liquid Chromatography (LC) with n-hexane as mobile phase and neutral Al2O3 as stationary phase was set up for the PIB-BP separation from PPM. The result appeared to be satisfying that the red mixture with PIB and homopolymer of BP turned into golden yellow after elution, with alkylation degree of 86%. Besides, the route of hydrolysis of PIB terminated with benzyl acetate to prepare PIB-PB was established. In addition, in order to realize the combination of esterification and thermal polycondensation, aspartic acid monomer as well as glutamic acid monomer was conducted these reactions under different acid catalysts including concentrated sulfuric acid, concentrated hydrochloric acid and concentrated phosphoric acid. The results indicated that aspartic acid was more suitable for thermal polycondensation, and the esterification could be undertaken with concentrated hydrochloric acid at first. After the esterification complete, the concentrated phosphoric acid was added to the solution to conduct the thermal polycondensation. Thermal polycondensation of amino acid monomer grafted with PIB was carried on to produce a comb-shape copolymer PASP-g-PIB with Mn of 6400 g/mol and Mw/Mn of 1.78 under the catalyst of DCC and the concentrated phosphoric acid.