Li Xiuru, Su Yali, Chen Qingyong, Lin Ying, Tong Yuejin, Li Yuesheng
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P R China.
Biomacromolecules. 2005 Nov-Dec;6(6):3181-8. doi: 10.1021/bm050531l.
A series of novel AB3-type monomers were prepared from nontoxic natural gallic acid and amino acids. These monomers were then melt-polycondensed in the presence of MgO as a catalyst via a transesterification process at 170-190 degrees C to yield the hyperbranched poly(ester-amide)s bearing terminal acetyl groups. FTIR and NMR spectra confirmed the structures of all the monomers and polymers. The degrees of branching, estimated from 1H NMR and quantitative 13C NMR spectra, were 0.50-0.68. These hyperbranched polymers displayed moderately high molecular weights. Hydrolytic and enzymatic degradation studies were carried out in vitro at 37.5 degrees C in NaOH hydrotropic solution and in Tris-HCl buffer (pH = 8.6) containing proteinase K, respectively. The results indicate that the hyperbranched poly(ester-amide)s are degradable hydrolytically as well as enzymatically, and the rate of hydrolytic degradation increases with the pH value of the solution.
一系列新型AB3型单体由无毒天然没食子酸和氨基酸制备而成。然后，这些单体在MgO作为催化剂存在的情况下，通过酯交换过程在170 - 190℃下进行熔融缩聚，以生成带有末端乙酰基的超支化聚（酯 - 酰胺）。FTIR和NMR光谱证实了所有单体和聚合物的结构。由1H NMR和定量13C NMR光谱估算的支化度为0.50 - 0.68。这些超支化聚合物显示出中等较高的分子量。分别在37.5℃下于NaOH水溶助长剂溶液中以及在含有蛋白酶K的Tris - HCl缓冲液（pH = 8.6）中进行了体外水解和酶降解研究。结果表明，超支化聚（酯 - 酰胺）可进行水解和酶解降解，且水解降解速率随溶液的pH值增加而增大。
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