低分子量N,O-羧甲基壳聚糖的合成及吸湿保湿性能

采用不同反应温度、反应时间和低分子量壳聚糖与氯乙酸摩尔比,在非均相反应体系中合成了不同取代度的低分子量N,O-羧甲基壳聚糖。当反应温度为60°C,反应时间为4h,低分子量壳聚糖与氯乙酸投料比为1∶1.5时,目标产物的取代度可达71%。吸湿保湿性能测定表明:取代度越大,低分子量N,O-羧甲基壳聚糖的吸湿保湿性越好,在相对湿度为81%,取代度从27%增大到71%时,其吸湿性从32.14%增大到37.27%,保湿性从310.72%增大到348.69%。     

N-羧丙酰壳聚糖钠增强改性壳聚糖棒材

采用原位沉析法制备N-羧丙酰壳聚糖钠增强改性的三维壳聚糖复合棒材, 并用傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、热重(TG)分析、扫描电镜(SEM)以及力学性能测试等方法研究复合棒材结构与性能之间的关系. FTIR分析表明, 壳聚糖分子中的氨基官能团和乙酰氨基官能团均与N-羧丙酰壳聚糖钠分子中的羧酸盐官能团发生强烈的静电相互作用. 加入N-羧丙酰壳聚糖钠后: 两种分子间产生强烈的静电相互作用, 限制了大分子链的运动, 使得大分子链趋于刚性, 同时复合棒材的层状叠加结构变得更加紧密, 提高了复合棒材的热稳定性与力学性能; 大分子链的刚性增强, 限制了分子链排入晶格, 从而降低了壳聚糖的结晶度. 当复合棒材中含有15% (w)的N-羧丙酰壳聚糖钠时, 其弯曲强度和弯曲模量可达156.0 MPa、5.3 GPa, 与纯壳聚糖棒材相比, 分别提高了68.8%、29.3%.因此, N-羧丙酰壳聚糖钠可有效地增强改性三维壳聚糖棒材, 该三维复合物棒材有望用作骨折内固定材料.     

N-琥珀酰壳聚糖的合成和性能研究

通过控制反应时间，制备了一系列取代度不同的N-琥珀酰壳聚糖。测定了产物的取代度、特性粘数、吸湿与保湿性，并用IR进行了结构表征。结果表明：壳聚糖在C2位上引入了琥珀酰基后可溶于水，其吸湿性与保湿性随取代度的增加而增强，且优于壳聚糖和透明质酸。     

羧甲基壳聚糖的取代度及保湿性

吸湿性;分子量;羧甲基壳聚糖的取代度及保湿性     

N－羧丁基壳聚糖的吸湿性和保湿性

透明质酸具有良好的吸湿、保湿性能 ,被认为是“理想的天然保湿因子”。但是从动物组织中提取的产品 ,工艺复杂 ,成本较高 ;而发酵法制备的产品 ,还完全达不到天然提取产品的理化性能 [1] 。甲壳素脱乙酰基后得到的壳聚糖具有一定的水分调节能力 [2 ] 。但壳聚糖有较强的分子间氢键 [3] ,只能溶于有机或无机酸的溶液中 ,而不溶于水 ,从而限制了它在日化方面的广泛应用。为此 ,近年来已制备了一系列水溶性壳聚糖衍生物 [4 ,5] ,其中与透明质酸具有相近结构的羧甲基壳聚糖的研究报道较多[5～ 7] ,但在相近分子量时仍达不到透明质酸的保湿效果 …     

(2-羟基-3-丁氧基)丙基-羟丙基壳聚糖的应用性质

表面活性;泡沫性;乳化性;吸湿保湿性;(2-羟基-3-丁氧基)丙基-羟丙基壳聚糖的应用性质     

羧乙基壳聚糖的合成及表征

壳聚糖是甲壳素的N-脱乙酰基产物,并具有良好的螯合重金属离子、纺丝性和成膜性,且无毒副作用,广泛应用污水处理、食品、生物医用材料等领域[1-3].水溶性壳聚糖的合成及应用近年来文献报道很多[4-8].但对于水溶性羧乙基壳聚糖的合成报道较少.     

低分子量壳聚糖制备与应用研究进展

低分子量壳聚糖因具有特殊的生物活性而日益受到人们的关注。本文概要介绍了近5年来国内外低分子量壳聚糖的研究进展,包括低分子量壳聚糖的制备方法,如酶降解法、酸水解法、氧化降解法、物理法等,以及低分子量壳聚糖在农业、医药、抗菌、化妆品、食品等方面的应用。     

新型载药壳聚糖季铵盐的合成、结构与性能

通过羧甲基壳聚糖接枝二甲基十八烷基环氧丙基氯化铵, 制备了一系列不同取代度和分子量的羧甲基壳聚糖十八烷基季铵盐(QACMC). 用傅立叶变换红外(FTIR)光谱、核磁共振谱(1H-NMR)、X射线衍射(XRD)谱、差式扫描量热法(DSC)等对其分子结构、结晶和热性能进行研究, 同时研究QACMC的吸湿保湿性能, 并与透明质酸(HA)、壳聚糖(chitosan)和羧甲基壳聚糖(CMC)进行比较. 结果表明, QACMC具有较好的结晶性和热稳定性, 结晶度可达72.3%; 其吸湿保湿性低于透明质酸(HA)和羧甲基壳聚糖, 而受季铵基团取代度和QACMC分子量的影响, 羧酸盐和季铵盐两种亲水基团对QACMC吸湿性的影响不具有协同作用; QACMC对亲脂性药物盐酸米诺环素的载药率可达10.9%(质量分数), 远高于壳聚糖和羧甲基壳聚糖.     

壳聚糖季铵化衍生物的吸湿性与保湿性

壳聚糖季铵化衍生物的吸湿性与保湿性许晨，卢灿辉（福建师范大学高分子研究所福州３５０００７）关键词壳聚糖季铵盐，壳聚糖衍生物，吸湿性，保湿性壳聚糖是从虾、蟹等废弃甲壳中提取得到的一种生物活性物质［１，２］，由于其特有的直链聚阳离子结构，成膜附于角蛋白与...     

Moisture effects on the glass transition and the low temperature relaxations in semiaromatic polyamides

The influence of moisture absorption on the primary (glass) transition (T_a or T_g) and the low temperature relaxations of semiaromatic amorphous polyamides synthesized by isomeric aliphatic diamine and metha or para oriented phthalicdiacids has been investigated by means of differential scanning calorimeter (DSC) and dynamic mechanical thermal analyser (DMTA). The glass transition of semiaromatic polyamides was lowered due to the water absorption, and the β and the γ relaxations were as well. From the observed T_g and the difference in the heat capacity, the calculated T_g depression per 1 wt % water content was 12.3 K and the result was in good agreement with the experimental data. The depression of the glass transition may be expressed by the same manner as the plasticization of nylon 6 by water. The depressed β relaxation observed in the specimen containing a few percent of moisture was splitted into two transitions due to the reduction of water content, of which one was the elevation of the T_β and another was the simultaneous appearance of the T_γ, and then the single T_γ solely was observed for the completely dried specimen. The T_γ seemed to be merged into or not to be observed by the large and broad T_β transition when the sample was governed by a few percent of water, then it was emerged from the T_β due to water desorption. Thus, the T_β is believed to arise from the intermolecular hydrogen bonding between water molecules or between water and amide groups in wet polyamides. In addition, the γ relaxation originated from the peptide groups is attributable to the inter- and intramolecular hydrogen bonding between amide groups. © 1997 John Wiley & Sons, Inc. J Polyn Sci B: Polym Phys 35: 807–815, 1997     

低分子量聚丙烯酰胺研究进展

综述了低分子量聚丙烯酰胺的合成方法及应用研究进展,同时对其未来的发展方向进行了展望.     

基于杯芳烃和紫精的电刺激响应二元水凝胶

基于上缘四脯氨酸修饰杯[4]芳烃和各种紫精客体分子的相互作用, 我们构筑了一类新型的二元超分子水凝胶. 得到结果显示, 在酸性条件下, 溴化紫精盐最易于促进四脯氨酸修饰杯[4]芳烃形成水凝胶. 并且经落球法测定了所制备水凝胶的凝胶-溶胶转变温度, 采用原子力显微镜和扫描电子显微镜表征了水凝胶的微观形态, 发现紫精的侧链对水凝胶性质具有显著影响, 包括凝胶-溶胶转变温度和微观形态. 值得注意的是, 该类水凝胶不仅具有优良的电刺激响应性, 而且能够通过化学、pH和热等多种因素进行调控.     

低截留分子量PPES超滤膜的制备

以杂萘联苯聚醚砜(PPES)为膜材料、N-甲基吡咯烷酮(NMP)为溶剂、有机小分子丙醇(PrOH)和无机小分子氯化锂(LiCl)作为混合添加剂,采用相转化法制备超滤膜.研究了聚合物浓度、混合添加剂配比、凝胶浴温度等对膜结构和性能的影响.结果表明:随聚合物浓度的增大,膜的纯水通量下降,截留率升高;混合添加剂,在PrOH含量为12%、LiCl含量为1.5%时,可制得纯水通量为252 L/(m2·h),对聚乙二醇1000(PEGl000)截留率为96%的超滤膜;随凝胶浴温度的升高,膜的纯水通量增加.     

低温焦油馏分的组成和统计结构表征

用ＧＣ－ＭＳ研究了代温焦油第４和第５蒸馏馏分的组成和统计平均结构。研究表明,平朔煤低温焦油第４（２３０～２７０℃）和第５（２７０～３４０℃）蒸馏馏分,由脂肪烃类化合物和非脂肪烃类化合物两大类组成。第４和第５馏分的平均分子量分别为２８０．２和２９６．２和２９６．７。第４蒸馏馏分中的非脂肪烃化合物主要由酚类２２．４４％和取代萘酚６２．７３％组成。第５蒸馏馏分中的非脂肪烃化合物主要酚类８．６９％,芳香基     

Hydrogen-bonded Supramolecular Hydrogels Derived from 3,3',4,4'-Benzophenonetetracarboxylic Acid and Hydroxylpyridines

In this paper, four gelators (defined as G1 – G4 ) were prepared from 3,3′,4,4′‐benzophenonetetracarboxylic acid (BPTA) and para‐hydroxylpyridine or meta‐hydroxylpyridine at molar ratios 1:2 and 1:4 respectively, and characterized by ¹H NMR, IR, UV‐Vis spectra and elemental analysis. Due to the amphiphilic features, all the gelators were able to gel water via cooling their aqueous solution under different stimulations. The structure of the assembling fibers and the macroscopic properties of the gels were investigated by multiple techniques. The results indicated that the minimum gelator concentration (MGC) increased by the order of G1 , G2 , G3 and G4 , while the gel‐to‐sol dissociation temperature (T_gel) decreased by the same order, which were explained from the assembling structures of the gels.     

Moisture permeation of clothing

The manner in which the wetting and drying behavior of a textile fabric depends upon the properties of the fibers comprising it is of both practical and theoretical significance. The consumer is justifiably interested in the relationship of fiber content to such serviceability criteria as wicking, solubility, wettability, and speed of drying. At the same time, the extent to which the drying of textiles conforms with or departs from theory is of scientific interest, particularly if noteworthy distinctions in behavior among fabrics can be related to intrinsic fiber properties or geometry of the textile structure. This work was undertaken to answer some practical questions about fiber-fabric-water relationships. Especially of interest was the extent to which rate of fabric drying might depend upon (a) fiber moisture regain, and (b) speed of capillary migration. These and other aspects of the general problem were examined in the light of pertinent theory in connection with appropriate practical findings. This revised version was published online in July 2006 with corrections to the Cover Date.     

镜煤抽提物热解特性的实验研究

采用热重分析仪和热解/红外联用仪（Py-FTIR）考察了镜煤四氢呋喃抽提物的热解过程。热重的研究结果表明：抽提物的热解失重行为与镜煤的热解失重行为有很大不同，前者有两个明显的DTG峰，190 ℃左右时出现一个DTG峰，在439 ℃出现第二个DTG峰，与镜煤相比，抽提物的失重速率显著高于镜煤，且最大失重峰向低温区移动。抽提物的热解产物中脂肪烃的释放量多于镜煤，而且脂肪烃类产物释放的温度区间小，说明脂肪烃的释放更集中和快速，但是甲烷的生成量明显少于镜煤；抽提物热解产物中有少量的CO2生成，几乎没有产生CO。