共查询到19条相似文献,搜索用时 62 毫秒
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研究了在水媒介中,利用微波加热使壳聚糖发生羧甲基改性反应。探讨了碱化时间、微波加热时间、投料比等工艺条件对壳聚糖羧甲基化程度及产物收率的影响,并对产物进行了红外光谱分析、取代度测定、粘度分析。确定最佳工艺条件。壳聚糖:氢氧化钠:氯乙酸=1:15:12,碱化时间=2h,微波加热时间=25min,制得羧甲基壳聚糖取代度和收率分别为0.71和83%。 相似文献
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由蟹壳制备O-羧甲基壳聚糖 总被引:1,自引:0,他引:1
以蟹壳为原料,研究了O-羧甲基壳聚糖的制备原理和方法;研究了盐酸浓度以及甲壳素在脱乙酰反应时不同反应时间和反应温度对壳聚糖性能的影响。 相似文献
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羧甲基壳聚糖的制备及应用研究 总被引:4,自引:0,他引:4
合成了具有良好水溶性的羧甲基壳聚糖,并将产品水溶液作为絮凝剂应用于中药制剂的提纯。初步讨论了影响絮凝效果的因素。利用紫外分光光度计对提纯后的药液进行了分析,结果表明絮凝工艺优于传统的水提醇沉工艺。 相似文献
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以羧甲基壳聚糖(CMCHS)为主要原料,采用静电脉冲液滴发生器制备羧甲基壳聚糖离子配位微球。光学显微镜观察微球具备规整形貌,扫描电镜分析显示干球粒径约为100μm且表面呈多孔结构;红外光谱证明其内部具有由CMCHS上的羧酸根与Ca^2 配位形成的羧酸盐结构。溶胀实验表明,CMCHS溶液浓度、金属离子种类及其浓度等制备条件均影响微球的溶胀性能.且其溶胀行为对pH值较敏感。药物体外释放初步研究表明,CaCl2浓度和释放介质pH值均对微球的释放性能产生影响。研究对其进一步应用于药物释放等领域具有重要意义。 相似文献
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以在适宜条件下制得的羧甲基壳聚糖为基础,研究了该羧甲基壳聚糖对高岭土的絮凝作用,同时利用EDTA络合滴定法,研究了羧甲基壳聚糖对Pb2 的吸附作用,从而对羧甲基壳聚糖应用于水处理进行了探讨。 相似文献
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用氯乙酸改性处理壳聚糖(CS)制备羧甲基壳聚糖(CMCS),采用湿法纺丝法制备CMCS纤维,考察了纺丝原液浓度、醋酸水溶液体积分数、凝固时间对CMCS纤维力学性能的影响;通过傅里叶变换红外光谱、X射线衍射以及热失重分析对CS,CMCS及其纤维进行表征。结果表明:CMCS发生了羧甲基取代,同时CMCS结晶度降低;CMCS纤维结构中含有结合水,热分解温度为270℃;纺丝原液CMCS的质量分数为50%,醋酸水溶液的体积分数为2%、凝固时间为12 min时,CMCS纤维的断裂强度达0.644 cN/dtex。 相似文献
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Flávia OMS Abreu Carla Bianchini Tarso BL Kist Maria Madalena C Forte 《Polymer International》2009,58(11):1267-1274
BACKGROUND: Hydrogels of alginate (ALG) with partially carboxymethylated chitosan (CMCHI) have been produced for drug delivery, based on the interactions between the negative groups and an ionic crosslinker. In the present work, CMCHI was used to evaluate the influence of amino groups that are positively charged at pH = 4 and 6 on the ALG–CMCHI core–shell hydrogel preparation. An ANOVA statistics tool was used to evaluate the effect of composition, pH and chitosan chemical nature on the morphology and swelling properties of the hydrogels in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). RESULTS: The ALG–CMCHI core–shell hydrogels presented smaller (ca 2.3 µm) and more homogeneous microparticles than those with unmodified chitosan (ca 5.5 µm). The ALG–CMCHI hydrogels showed higher thermal stability and lower degree of swelling in SGF (314%) compared to those with chitosan (708%), since in the former hydrogels the protective layers that surround the particles are negatively charged. CONCLUSION: CMCHI can replace chitosan in the production of core–shell hydrogels with improved properties since the negative charge surrounding the ALG–CMCHI particles favours a lower degree of swelling. The results point out a possible prevention of burst release in SGF, sustaining the swelling ability of the ALG–CMCHI core–shell hydrogels in SIF, promising appropriate drug release. Copyright © 2009 Society of Chemical Industry 相似文献