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以L-乳酸和环氧氯丙烷等原料,设计、合成出含L-乳酸基的聚丙三醇水凝胶。用核磁共振碳谱、X-射线光电子能谱和扫描电镜表征了其结构和形貌。通过控制反应条件,合成了不同L-乳酸基含量和平衡溶胀率的聚丙三醇水凝胶。化学滴定分析表明,在选定的合成条件下,L-乳酸基的引入率约为86%,其含量可达到17%。溶胀实验表明,凝胶具有显著的pH、离子强度敏感性和快速、可逆的响应速率。体外释药实验显示,载药凝胶具有随溶胀环境pH变化的释药性能。  相似文献   
2.
Novel amphoteric pH-sensitive hydrogels with pendant carboxyl and backbone tertiary amine groups were designed and synthesized. First, ethylenediaminetetraacetic dianhydride (EDTAD) reacted with butanediamine (BDA) via N-acylation reaction to give a polyamide prepolymer with pendant carboxyl groups (PEB–COOH); then amino-terminated poly(ethylene glycol) 500 (ATPEG500) was added as a cross-linking agent to produce the desired network polymer (PEB–ATPEG500–COOH). The obtained hydrogels are potentially degradable and non-toxic since its backbone and cross-linking sections are both linked by amide bonds and all monomers have been proved as safe. FTIR, 1H NMR, 13C NMR and ninhydrin reaction method were employed to qualitatively and quantitatively characterize the obtained polymers. The effect of cross-linking agent amount, characterized by the molar ratios (Rm) of NH2 groups in ATPEG500 to pendant COOH groups in PEB–COOH, on the swelling behavior of the proposed hydrogel was examined. The results indicate that the equilibrium swelling ratio decreases and the pH-sensitivity becomes retarded with the increase of Rm. For PEB–ATPEG500–COOH hydrogels with Rm no more than 0.42, they exhibited three SRe variation zones at pH 2–4, pH 6–7 and pH 9–11, respectively, suggesting obvious and interesting amphoteric pH-sensitivity. In addition, the swelling kinetics tests on PEB–ATPEG500–COOH with Rm = 0.32 reveal that the swelling kinetics of proposed hydrogel follows a Fickian diffusion process in media of pH 7, and an anomalous diffusion process in media of pH 2 and 11. The above obtained results will facilitate the application of this proposed hydrogel in biomedical fields, particularly in the drug controlled release.  相似文献   
3.
Biologically inspired silk fibroin grafted polyacrylonitrile (SF-g-PAN) filtration membrane was prepared using ZnCl2 aqueous solution as solvent, avoiding the use of organic solvents.  相似文献   
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