共查询到19条相似文献,搜索用时 93 毫秒
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介绍了多种甲壳素衍生物的制备工艺和生产方法 ,包括壳聚糖、羧甲基甲壳素、羧甲基壳聚糖、乙酰化壳聚糖、羧丙 (乙 )基壳聚糖、微晶甲壳素及壳聚糖、盐酸氨基葡萄糖、甲壳素硫酸盐、溴化甲壳素、N-乙基壳聚糖、季铵化壳聚糖、壳聚糖接枝共聚产物等十多种。 相似文献
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将壳聚糖进行液态均相配合反应制得壳聚糖锰配合物,IR、元素分析及热分析等检测证实了壳聚糖锰配合物中配位键的存在,且显示壳聚糖锰配合物存在有利于壳聚糖高分子链断裂的弱势结构。以H2O2对壳聚糖.Mn(Ⅱ)配合物及壳聚糖进行氧化降解,考察降解过程中粘度的变化及降解产物分子量分布,在相同的降解条件下,壳聚糖锰配合物的降解速度明显高于壳聚糖,且降解产物分子量分布较壳聚糖直接降解窄。对壳聚糖锰配合物降解反应动力学研究表明壳聚糖锰配合物对H2O2分解不存在催化作用,其降解反应与壳聚糖的差异只与其结构有关。对降解产物进行脱金属处理,所得低聚壳聚糖含锰量为0。 相似文献
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在简单均相体系下.研究了壳聚糖及丁二酸酐酰化壳聚糖在双氧水中的降解特性。采用鸟氏粘度计,利用一点法测量了降解过程中壳聚糖及丁二酸酐酰化壳聚糖的分子量,讨论了该体系下壳聚糖及丁二酸酐酰化壳聚糖的降解速率.通过红外光谱分析了双氧水对低分子量壳聚糖和低分子量丁二酸酐酰化壳聚糖结构的影响。结果表明.在该体系下·壳聚糖及丁二酸酐酰化壳聚糖的降解主要发生在反应开始后的2~3h内.此后降解产物的分子量逐渐趋于20000;相同条件下,丁二酸酐酰化壳聚糖的降解程度高于壳聚糖;红外光谱表明.采用该降解体系制备的降解产物主链结构基本没有发生变化。 相似文献
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壳聚糖衍生物的红外光谱分析 总被引:29,自引:1,他引:28
合成了以下多种壳聚糖衍生物并测定了它们的红外光谱。这些衍生物是羧酸化壳聚糖 ,苯甲酰化壳聚糖 ,氰乙基壳聚糖 ,羟丙基壳聚糖 ,羟乙基壳聚糖 ,N -羧甲基化壳聚糖 ,壳聚糖的苯甲醛西佛碱 ,N -乙基壳聚糖 ,N -丁二酰化壳聚糖 ,N -顺丁烯二酰化壳聚糖 ,N -邻苯二甲酰化壳聚糖和N -乙酰化壳聚糖。观察到随壳聚糖脱乙酰度的增加 ,酰胺Ⅰ谱带移向低频 ,而酰胺Ⅲ谱带和醇羟基谱带移向高频 ,结果可用氢键的变化加以解释。脂肪族酰化壳聚糖的取代基长度对C =O位置影响很小 ,它们的C =O都能与邻近的N -H和O -H基生成相似的氢键。氰乙基壳聚糖的取代度影响了C -O谱带的位置 ,低取代的 1 0 70cm- 1 和 1 0 30cm- 1 双峰在高取代时被 1 0 61cm- 1 单峰所代替。通过IR测定 ,对丁二酰化壳聚糖和顺丁烯二酰化壳聚糖观察到含自由羧基端的线形取代 ,对邻苯二甲酰化壳聚糖 ,在反应程度较高时还出现环状取代。羧酰化壳聚糖、氰乙基壳聚糖和邻苯二甲酰化壳聚糖的取代度可分别用吸光度比A1 740 /A1 52 7,A2 2 4 9/A1 52 7和A1 71 2 /A1 391 测定 相似文献
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甲壳素衍生物的制备工艺 总被引:6,自引:0,他引:6
介绍了多种甲壳素衍生物的制备工艺和生产方法,包括壳聚糖、羧甲基甲壳素、羧甲基壳聚糖、乙酰化壳聚糖、羧丙(乙)基壳聚糖、微晶甲壳素及壳聚塘、盐酸氨基葡萄糖、甲壳素硫酸盐、溴化甲壳素、N-乙基壳聚糖、季铵化壳聚糖、壳聚糖接枝共聚产物等十多种。 相似文献
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壳聚糖用作食品的保鲜剂具有良好的成膜性和强的抗菌保鲜防腐能力,再加上其来源广泛、天然、无毒副作用及涂膜保鲜简单易行等诸多优点,因而受到了国内外的广泛研究。本文综述了以壳聚糖为主要原料的壳聚糖复合物,如壳聚糖-有机酸复合物、壳聚糖-维生素C复合物、碘化复合物、壳聚糖-纳米材料复合物、壳聚糖-CaCl2-乳清蛋白-柠檬酸复合物、钙复合巯基化壳聚糖复合物、壳聚糖稀土复合物在水果防腐保鲜方面的应用,并对壳聚糖复合物的保鲜前景进行了展望。 相似文献
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《Reactive and Functional Polymers》2002,50(2):181-190
The adsorption of Cu(II) ions onto chitosan and cross-linked chitosan beads has been investigated. Chitosan beads were cross-linked with glutaraldehyde (GLA), epichlorohydrin (ECH) and ethylene glycol diglycidyl ether (EGDE) in order to obtain sorbents that are insoluble in aqueous acidic and basic solution. Batch adsorption experiments were carried out as a function of pH, agitation period, agitation rate and concentration of Cu(II) ions. A pH of 6.0 was found to be a optimum for Cu(II) adsorption on chitosan and cross-linked chitosan beads. Isotherm studies indicate Cu(II) can be effectively removed by chitosan and cross-linked chitosan beads. Adsorption isothermal data could be well interpreted by the Langmuir equation. Langmuir constants have been determined for chitosan and cross-linked chitosan beads. The experimental data of the adsorption equilibrium from Cu(II) solution correlated well with the Langmuir isotherm equation. The uptakes of Cu(II) ions on chitosan beads were 80.71 mg Cu(II)/g chitosan, on chitosan-GLA beads were 59.67 mg Cu(II)/g chitosan-GLA, on chitosan-ECH beads were 62.47 mg Cu(II)/g chitosan-ECH and on chitosan-EGDE beads were 45.94 mg Cu(II)/g chitosan-EGDE. The Cu(II) ions can be removed from the chitosan and cross-linked chitosan beads rapidly by treatment with an aqueous EDTA solution and at the same time the chitosan and cross-linked chitosan beads can be regenerated and also can be used again to adsorb heavy metal ions. 相似文献
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壳聚糖的脱乙酰度直接影响壳聚糖的物理化学和生物特性。在乙酸-水-甲醇体系中研究壳聚糖的乙酰化反应工艺,考察了反应时间、壳聚糖质量浓度对乙酰化反应的影响,优化了反应条件。研究表明,反应时间为6h时,壳聚糖乙酰化反应基本完全,乙酰化反应后,相对重均分子质量基本不变,壳聚糖相对分子质量分布变宽。在优化后的反应条件下,改变乙酸酐加入量分别制备了脱乙酰度为76%,64%和54%的不同脱乙酰度的壳聚糖。芘荧光光谱研究表明,壳聚糖的临界聚集浓度(CSC)随脱乙酰度的降低而增加。 相似文献
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以壳聚糖和二硫代二丙酸二甲酯为原料,通过乙酰化改性,成功制备了壳聚糖衍生物。然后以壳聚糖/壳聚糖衍生物为原料,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,合成了壳聚糖气凝胶/壳聚糖衍生物气凝胶。通过红外光谱(FT-IR)、X射线衍射(XRD)和热重分析(TG)研究了壳聚糖/壳聚糖衍生物的结构性能;同时采用扫描电镜(SEM)对壳聚糖气凝胶/壳聚糖衍生物气凝胶的形貌进行了表征;并且探究了壳聚糖气凝胶/壳聚糖衍生物气凝胶对Cu2+的静态吸附实验。FT-IR结果表明壳聚糖衍生物被成功地合成;XRD和TG分析表明相较于壳聚糖,壳聚糖衍生物的结晶度和热稳定性均降低;SEM显示衍生物气凝胶的孔的数量增多。吸附实验结果表明壳聚糖衍生物气凝胶的吸附性能有了较大提高;在25℃,吸附剂添加量50.0mg且Cu2+溶液初始质量浓度100mg/L,pH值5时,壳聚糖衍生物气凝胶在60min时达到吸附平衡,最大吸附量为48.26mg/g,比未改性的壳聚糖气凝胶的吸附量提高了63.37%。 相似文献
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Cristina Ardean Corneliu Mircea Davidescu Nicoleta Sorina Neme Adina Negrea Mihaela Ciopec Narcis Duteanu Petru Negrea Daniel Duda-Seiman Virgil Musta 《International journal of molecular sciences》2021,22(14)
The biomedical and therapeutic importance of chitosan and chitosan derivatives is the subject of interdisciplinary research. In this analysis, we intended to consolidate some of the recent discoveries regarding the potential of chitosan and its derivatives to be used for biomedical and other purposes. Why chitosan? Because chitosan is a natural biopolymer that can be obtained from one of the most abundant polysaccharides in nature, which is chitin. Compared to other biopolymers, chitosan presents some advantages, such as accessibility, biocompatibility, biodegradability, and no toxicity, expressing significant antibacterial potential. In addition, through chemical processes, a high number of chitosan derivatives can be obtained with many possibilities for use. The presence of several types of functional groups in the structure of the polymer and the fact that it has cationic properties are determinant for the increased reactive properties of chitosan. We analyzed the intrinsic properties of chitosan in relation to its source: the molecular mass, the degree of deacetylation, and polymerization. We also studied the most important extrinsic factors responsible for different properties of chitosan, such as the type of bacteria on which chitosan is active. In addition, some chitosan derivatives obtained by functionalization and some complexes formed by chitosan with various metallic ions were studied. The present research can be extended in order to analyze many other factors than those mentioned. Further in this paper were discussed the most important factors that influence the antibacterial effect of chitosan and its derivatives. The aim was to demonstrate that the bactericidal effect of chitosan depends on a number of very complex factors, their knowledge being essential to explain the role of each of them for the bactericidal activity of this biopolymer. 相似文献
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改性壳聚糖对处理污泥脱水性能影响的研究 总被引:7,自引:0,他引:7
研究了聚合氯化铝、壳聚糖和3种羧甲基壳聚糖(N-羧甲基壳聚糖、N,O-羧甲基壳聚糖和O-羧甲基壳聚糖)絮凝剂对污泥的脱水性能作用。实验结果表明,羧甲基壳聚糖作为絮凝剂对污泥进行脱水时,形成的絮体强度大,不易破碎,对污泥脱水的效果明显好于普通絮凝剂。在3种所研究的羧甲基壳聚糖中,N-羧甲基壳聚糖对污泥的脱水效果最好,污泥比阻抗最低,与未加絮凝剂时相比,含水率从99.1%下降到73%,污泥的体积减少为原来的1/30,热值提高为原来的40倍。 相似文献
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Wool fabrics were treated with the biopolymer chitosan under conditions which conferred shrinkresistance and dyeing improvement. In order to enhance chitosan absorption in wool, two different oxidative chemical pretreatments, hydrogen peroxide and permonosulphuric acid, were performed on wool fabrics prior to chitosan application. Chitosans of three different molecular masses, but with the same acetylation degrees of, were applied to unpretreated and oxidated wool and the influence of the molecular mass of chitosan and the oxidative pretreatment on shrink-resistance and dyeing behaviour was assessed. In conclusion, both molecular mass and oxidative pretreatment exert an influence on shrink-resistance. However, dyeing behaviour depends only on the presence of chitosan on wool fibre. 相似文献