天冬氨酸与谷氨酸共聚反应研究

The copolycondensation of L-aspartic acid and L-glutamic acid

以天冬氨酸(A)和谷氨酸(G)为单体,在1,3,5-三甲苯(TB)和环丁砜(SUL)混合溶剂中,分别进行两者均聚及共聚反应,考察了溶剂配比、催化剂用量、单体配比、反应温度和时间等因素对产率、聚合物分子量和分子量分布的影响,并用FTIR和13C-NMR对聚合产物进行了结构表征。结果表明,随着混合溶剂中TB含量增加、催化剂用量增加、反应温度升高和时间延长,产率和聚合物的分子量均增加。但催化剂用量过多和反应温度过高对聚合是不利的。天冬氨酸的反应活性大于谷氨酸,两者可以进行共聚反应,产率、共聚物的分子量及分子量分布随单体配料中A含量的增加而增大。不同A/G配比下得到产物的GPC谱图曲线为较窄的单峰分布,分子量分布指数(Mw/Mn,MWD)从1.34到1.87,数均分子量(Mn)范围从6000到11900。

The copolycondensation of L-aspartic acid （A） and L-glutamic acid （G） was conducted in sulpholane, 1, 3, 5-trimethyl benzene or mixtures of these solvents. The effects of varying the dosage of the phosphoric acid catalyst, monomer ratios, solvent ratios, reaction temperature and time on yield, molecular weight and average molecular weight distribution （^-Mw/^-Mn, MWD） of the polymer products were investigated. The yield and molecular weight were found to increase with increasing concentration of phosphoric acid, proportion of 1, 3, 5- trimethyl benzene in the mixed solvent, reaction temperature or time. L-aspartic acid is more reactive than L-glutamic acid and the molecular weight of the copolymer increases with increasing monomer ratio of A to G. The GPC traces of the copolymers of L-aspartic acid and L-glutamic acid （PAG） obtained with different monomer ratios exhibit unimodal narrow distributions with number-average molecular weight （^-Mn） in the range of 6000 to 11900 and polydispersity in the range of 1.34 to 1.87.