英语翻译

英语翻译
英语翻译

英语翻译
chitosan
Chitosan is chitin off after the reaction of products, acetylation level (de-acetylating D.D) determines the macromolecular chain amino (NH2) how many, and the content of D.D increase, because of the son and amino matrix chitosan in dilute acids solution charged groups increased, polyelectrolytes charge density increases, the result will inevitably lead to its structure, properties and performance since the change, TangXi shell gather solution properties research have neglected D.D value on the equation. Such VANDUM had studied in different ionic strength in dilute solution of chitosan molecules in the influence of size and viscosity. Results showed that ionic strength different can change the expansion of the linear cluster without rules changed molecular size and degree of viscosity, according to the different characteristics of D.D chitosan MARK - HOUWINK equation, the results show that the measuring constant K A value D.D value with the change. Thus HOUWINK equation by MARK - A regular constant K, depends on the deacelation degree of chitosan, take off, and in the same changes, when the molecular weight off the deacelation degree with increased, chitosan in dilute solution viscosity and molecular size, characteristics, and expand factor etc increase than and spatial characteristics of A resistance factor as the deacelation degree off decreased. Thus in any one within the scope of chitosan samples by relatively simple characteristics can be calculated its viscosity measurements, the average molecular weight, thus can accumulate some basic data for further research work.
Because of chitosan and chitin has following reactivity and easy to be some chemical reagent decorate, so this research work more, also have achieved remarkable results. Through various methods to the properties of chitosan by freezing sodium hydroxide modified. Abroad - sodium dodecyl sulfate system of simple steps the preparation of CHITIN fibers fluoroalkyl - success. Alkylation produced different chain long and body let degrees of alkyl quaternary ammonium compounds, the QinGeXing acid or water of the increase of QinGeXing increases, this is because of molecule crystals structural damage and of generation. Mri (magnetic resonance imaging) study shows that the C6 position than C3 position is being replaced hydroxyl group. Also CHITIN fibers were alkyl - and thin QinGeXing significant improvement. This, in the later application of chitosan, a good value. Additionally also prepared the chitosan porous beads, for heavy metal with a claw cooperation, can also be used for biological materials immobilized reaction. Through iodinated halogenating preparation of chitosan transplant copolymers. Halogenating and iodinated are the main methods for chitosan function transform, which the group milder conditions, iodinated and can produce all sorts of reaction precursor. This reaction is easy to occur in C6 location value, plus for the preparation of cationic copolymer transplantation. The reaction conditions 308NM place in room temperature and ultraviolet light. All sorts of function group of chitosan rebuilding also includes preparation hydroxyl chitosan.
壳聚糖
壳聚糖是甲壳质经脱乙酰反应后的产品,脱乙酰基程度(D.D)决定了大分子链上胺基(NH2)含量的多少,而且D.D增加,由于胺基质子化而使壳聚糖在稀酸溶液中带电基团增多,聚电解质电荷密度增加,其结果必将导致其结构,性质和性能上的变化,至今壳聚糖稀溶液性质方面的研究都忽略了D.D值对方程的影响.VANDUM等人曾研究了不同离子强度对壳聚糖在稀溶液中的分子尺寸和粘度的影响.结果认为离子强度不同会改变无规线团的膨胀度进而改变分子尺寸和特性粘度,通过对不同D.D壳聚糖进行MARK-HOUWINK方程常数的测定,结果表明K,A值随D.D值的变化.从而由MARK-HOUWINK方程常数K,A有规律地依赖于壳聚糖的脱乙酰度而变化,而且在相同分子量时,随着脱乙酰度的增加,壳聚糖在稀溶液中分子尺寸,特性粘度和扩张因子等增加,而特性比和空间位阻因子随着脱乙酰度的增加而减少.从而在适用范围内的任意一个壳聚糖样品通过比较简单的特性粘度测量,即可计算其平均分子量,从而可积累一些基础数据用于进一步的研究工作.
由于壳聚糖和甲壳质具有高化学反应活性并且易于被一些化学试剂修饰,因此这方面的研究工作进行的较多,也取得了可喜的成果.从而通过各种方法对壳聚糖进行了性质改良.国外通过冰冻氢氧化钠-十二烷基硫酸钠系统的简单步骤制备成功了烷基-CHITIN纤维.烷基化产生了各种不同链长和体容度的烷基卤素化合物,对水或甲酸的亲合性的增加,这种亲合性的增加是由于部分分子晶体结构破坏而产生的.核磁共振的研究表明C6位置上的羟基优于C3位置被取代.同时也制备了烷基-CHITIN纤维和薄膜.这种亲合性质的改善,在以后的壳聚糖应用中有良好的价值.另外还制备出了壳聚糖多孔小珠,对重金属有螯合作用,也可以用于生物材料的固定化反应.通过碘化卤化制备了壳聚糖移植共聚物.卤化与碘化的方法主要进行壳聚糖功能集团的改造,其中碘化条件温和,并可以产生各种反应的前体.该反应易于发生在C6位值上,另外用于制备阳离子移植共聚物.其反应条件在室温和紫外光308NM处进行.对壳聚糖各种功能集团的改造还包括制备羟基壳聚糖.

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