甲壳胺与Zn(Ⅱ)的配位作用及其红外光谱

甲壳胺是甲壳素脱乙酰基的产物，由于分子中游离氨基的存在，使它对一些金属离子，尤其是过渡金属离子具有较好的螯合能力，因而被作为重金属离子的天然吸附剂和高分子金属催化剂的研究对象［１，２］．目前文献报道的以Ｃｕ（Ⅱ）和Ｐｄ（Ⅱ）的配合物居多，且配合物的制...     

锌与甲壳胺络合物的制备

甲壳胺是甲壳素（2-乙酰氨基-1，4-个葡聚糖）脱乙酰基后的产物，学名为2-氨基－l．4-个葡聚糖，目前主要从虾、蟹壳中提取．这的用途很广，涉及诸多领域［1］．甲壳胺有杀菌、抑菌、消炎、促进伤口愈合的功能，有降低胆固醇，增强免疫力，体内排毒，防治胃溃疡和胃酸过多等功能，它对人体细胞无毒，且有亲和性，不与体液反应，也无抗原抗体反应，国内外已有许多报道[2]．本文报道克服甲壳胺只能溶于弱酸溶液的缺点，将其氧化降解成水溶性低聚物后，作为锌的配体，探讨二者络合的条件及所形成络合物的一些性质，以期能为人体补锌提供新的途…     

氨基聚硅氧烷对改性环氧树脂的形态与性能的影响

将带有Ｎ－（β－氨乙基）－γ－氨丙基侧基的聚二甲基硅氧烷与环氧树脂共混,制备了聚硅氧烷改性环氧树脂固化物。研究了氨基聚硅氧烷的氨基含量对改性环氧树脂的形态和性能的影响。结果表明,改性环氧树脂固化物的形态与性能主要依赖于氨基聚硅氧烷的氨基含量,在环氧树脂中引入适宜氨基含量的氨基聚硅氧烷,可在一定程度上降低其模量,提高其柔性,并可明显改善环氧树脂的表面性能。     

甲壳素/甲壳胺的聚集态结构及性能

制备了不同脱乙酰度的甲壳素,并对脱酰化反应进行了研究,找出了适合不同脱酰度甲壳素的溶剂,探讨了制样温度与甲壳胺膜的结晶形态和力学性能之间的关系,比较了甲壳素、甲壳胺及不同来源甲壳素的结晶形态.     

纳米甲壳素的制备、改性及应用研究进展

甲壳素是一种天然高分子化合物,具有来源广、可降解、生物相容、无毒和低抗原性等性质,但由于不溶于水和大多数有机溶剂,使其应用受到限制。由甲壳素制备的纳米甲壳素(甲壳素纳米晶须和甲壳素纳米纤维)能够在水中形成稳定均匀分散液,不仅具有甲壳素的性质,还有高长宽比、高表面积、低密度等性质,在其表面的羟基、N-乙酰基以及残留的胺基还可化学改性。本文综述了纳米甲壳素的制备,包括盐酸酸解、机械处理、2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)氧化、静电纺丝、溶解再生和脱N-乙酰基法,介绍了纳米甲壳素化学改性以及在增强、吸附和生物活性等方面应用。     

壳聚糖固体聚合物电池用膜

壳聚糖是甲壳素脱乙酰基的产物，具有良好的成膜性、生物相容性、环保以及价格低廉等特点。作为一种碱性高分子膜材料，近年来已成为聚电解质研究领域中的研究热点。本文综述了壳聚糖固体聚合物电池用膜的研究现状，其改性工艺主要包括共混、化学改性、质子酸掺杂、无机盐掺杂等方法，比较了各种工艺处理后壳聚糖固体聚合物电解质膜的性能差异，并就壳聚糖固体聚合物电解质膜中离子传导机理中有待解决的问题进行探讨，并提出了进一步改进壳聚糖固体聚合物电解质膜性能的研究思路。     

甲壳素和壳聚糖化学改性研究进展

甲壳素是一种天然多糖,脱除乙酰基的产物是壳聚糖,作为新型功能生物材料,它们已在水处理、日用化学品、生物工程和医药等领域得到了应用,但它们不溶于一般的有机溶剂,从而限制了其广泛应用.为此,甲壳素和壳聚糖的化学改性成为该材科研究的重要方向之一.本文综述了近年来甲壳素和壳聚糖化学改性方面的研究进展,着重介绍了选择性化学修饰的方法和发展动向.     

甲壳素/聚氨酯共混物膜结构与性能的研究

采用共混的方法分别制备了丁羟型和聚醚型聚氨酯／甲壳素共混膜(HPCT和PPCT系列),研究了甲壳素加入量对共混膜力学性能、热稳定性、溶胀性和吸湿性的影响,讨论了共混物膜在不同环境条件下的降解性能。结果表明随着甲壳素含量的增加共混材料对水的亲和力和热稳定性提高,当甲壳素质量分数分别为0．15和0．10时HPCT系列和PPCT系列具有较佳的力学性能,HPCT和PPCT系列分别在pH=7．0和pH=4．7的环境中具有良好的降解性能。     

多孔壳聚糖膜固定葡萄糖氧化酶活性的X射线微区分析

甲壳素(chitin)是无脊椎动物,特别是节肢动物,如虾、蟹及昆虫等的外骨骼重要组成部分,其学名为β(1,4)-2-乙酰氨基-2-脱氧-D-葡萄糖。壳聚糖是甲壳素脱乙酰基的衍生物,其结构上具有许多—NH2、—OH等反应基团,对蛋白质具有极高的亲和性,且具有生物相容性好、无毒、可生物降解等     

羧甲基壳聚糖对亚铁离子的吸附

壳聚糖是由甲壳素经脱乙酰基后得到的一种天然高分子氨基多糖 ,它是金属离子的良好配体 ,其配合物在工业、农业、食品、环保、医药等方面的应用已有许多研究 [1～ 4 ] .脱乙酰基后的壳聚糖溶解性有很大改善 ,但仍只能溶于酸或酸性水溶液 ,限制了它的推广应用 .通过化学改性的羧甲基壳聚糖 ( CMCS)具有良好的水溶性、保湿性、乳化性 ,其分子中含有— OH、— NH2 、—COOH等基团 ,能有效络合金属离子 [5] .人体对壳聚糖 -亚铁络合物的吸收远远大于传统的 Fe SO4 药物 [6 ] ,壳聚糖及其衍生物与 Fe2 的络合物有可能用于治疗缺铁性贫血 …     

壳聚糖水杨酸盐-明胶共混膜结构表征及其抗菌性

以溶液共混法成功制备出壳聚糖水杨酸盐－明胶共浊膜，用FT－IR、XRD、SEM表征了其结构，并测试了其吸水率，力学性能及抑菌性能。结果表明，壳聚糖水杨酸盐－胶胶共混膜中存在强烈的氢键相互作用及良好相容性，共混膜的力学性能随明胶含量增大而明显提高，当明胶含量为30％时，共混膜的抗张强度最大，其干、湿态抗张强度分别达99．9MPa和34．9MPa，比纯壳聚糖膜干，湿态抗张强度分别提高了99．8％有83．75，共浊膜抑菌性随明胶含量增加而下降，但其抑菌性仍明显高于壳聚糖膜。水杨酸的引入有利于改善其力学性能及抗菌性能，该共漫漫经膜作为一种潜在的伤口包扎材料，将具有广阔应用前景。     

壳聚糖/明胶/TiO2三元复合膜的制备与功能特性

纳米TiO2用阴离子表面改性剂SDS改性后,以溶液共混法制备了壳聚糖／明胶/TiO2复合膜,用FTIR、XRD、SEM、TEM表征了其结构与形态,并测试了其吸水率、透光率、力学性能和抑菌性能。进而探讨了复合膜中明胶和纳米TiO2含量对壳聚糖膜性能的影响。结果表明：复合膜中,壳聚糖、明胶和TiO2微粒间存在强烈的氢键相互作用,从而使明胶与壳聚糖具有良好的相容性,TiO2与壳聚糖、明胶分子间有很好的界面作用。适量TiO2的加入,可使壳聚糖／明胶共混膜的力学性能得到改善,明胶质量分数为0．30时,掺杂wTiO2为0．01、0．02的复合膜较壳聚糖／明胶共混膜的湿强及干态韧性分别提高了55．9％,40．8％和49．7％,47．9％。此外,复合膜的抑菌性能随明胶的增加而降低,但随TiO2的掺杂比的增加而增强,纳米TiO2的引入拓宽了壳聚糖和明胶两种天然高分子材料的应用范围。     

Improved Mechanical Properties of Poly(butylene succinate) Membrane by Co-electrospinning with Gelatin

Gelatin, a natural proteinous polymer, was used to co-electrospin with poly(butylene succinate) (PBS) in order to improve the mechanical properties of PBS membrane and facilitate its applications in biomedical field. The PBS/gelatin blend membranes have narrower distribution of fiber diameter and smoother surface than neat PBS membrane. The contact angles, water absorption rates and water uptakes of the PBS/gelatin blend membranes were measured, showing increased hydrophilicity. The interaction between PBS and gelatin was investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC). The mechanical properties of PBS/gelatin blend membranes in both dry and wet states were evaluated by uniaxial tensile tests. In the dry state, the PBS/gelatin blend membrane containing 10% gelatin has a 3-times increase in tensile strength without any adverse effect on ductility because of the existence of interaction between the two blend components, little change in crystallinity of PBS, and possible interaction between any adjacent fibers; the tensile strength and elongation at break are even better in the wet state attributed to some gelatin on fiber surfaces, which act as a binder in the presence of water. The potential applications of PBS/gelatin blend membranes were demonstrated by successful immobilization of thrombin, a clinically-used hemostatic drug. The thrombin-loaded membrane could be used for rapid hemostasis.     

Self‐organization of functional gradient structure in the biodegradable chitosan/poly(vinyl alcohol) blend film

Biologically inspired optimal structures combining the bioresorbable and bioactive properties are expected for the next generation of biomaterials. A compositional gradient structure was found to be spontaneously formed in the film of biodegradable chitosan/poly(vinyl alcohol) blend by casting aqueous solution on an aluminum dish. The formation of compositional gradient structure was confirmed by FTIR mapping measurement, DMTA measurement, and SEM observation on the freeze‐fractured cross section. In DMTA measurement, a broadening of the α‐relaxation curve corresponding to the glass transition was observed for the compositional gradient film, while a composition‐dependent single glass transition was observed for the homogeneous blend films. The resulted film with stable self‐organized compositional gradient exhibits novel physical properties inaccessible for the film of homogeneous blends obtained by casting from the same solution on a Teflon dish. The compositional gradient films present a unique combination of stronger stress and higher yield strain when compared with those of the homogeneous films at both dry and wet states. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3069–3076, 2005     

海藻酸盐/壳聚糖衍生物复合抗菌纤维

通过溶液纺丝法制备海藻酸盐/羧甲基壳聚糖（CMC）共混纤维,并用红外光谱,X射线衍射和扫描电镜对共混纤维进行了表征.结果表明：共混体系中的两种组分之间存在着较强的相互作用,有良好的相容性.当ωCMC=0.30时,共混纤维的干态抗张强度达到最大值,13.8cN/tex.当ωCMC=0.10时,纤维的干态断裂伸长率可达23.1%.纤维的湿态抗张强度和断裂伸长率随着CMC含量的增加而降低.CMC的引入,可显著提高纤维的吸水率.用壳聚糖季铵盐对纤维进行处理,可赋予纤维抗菌性.     

Characterisation and morphology of biodegradable chitosan / synthetic polymer blends

Chitosan has been used to form miscible, biodegradable blends with hydrophilic synthetic polymers as PVA and PEO. Characterisation of the blends by DSC, IR and microscopy analysis was made giving much attention to possible interactions of molecular polar group in the polymer chains. PVA/chitosan are found to be amorphous in the whole range of composition having one glass transition temperature. Molecular interactions in the pair of polymers are connected with amide group of chitosan and hydroxyl groups of PVA. PEO/chitosan blends stay amorphous up to 0.2 weight fraction of PEO. For a higher amount of PEO that polymer crystallises forming a spherulite crystalline structure. We correlate the overall kinetics of crystallisation and melting behaviour of solid, semicrystalline blends PEO/chitosan in the form of thin films for a set of PEO species of different blend composition with a morphological structure of the blends. Negative values of the Flory-Huggins interaction parameter due to specific interactions by hydrogen bonding through ether group of PEO and hydroxyl group of chitosan were evaluated. Amide groups do not participate in the molecular interaction between PEO and chitosan molecules. Avrami equation was applied to describe kinetics of crystallisation of pure PEO and PEO/chitosan blends of various compositions.     

Mucoadhesive and elastic films based on blends of chitosan and hydroxyethylcellulose

Mucoadhesive polymeric films have been prepared based on blends of chitosan and hydroxyethylcellulose. The blends have been characterized by IR spectroscopy, DSC, WAXD, TGA, SEM, and mechanical testing. It is demonstrated that the mechanical properties of chitosan are improved significantly upon blending with hydroxyethylcellulose. An increase in hydroxyethylcellulose content in the blends makes the materials more elastic. The thermal treatment of the blends at 100 degrees C leads to partial cross-linking of the polymers and formation of water-insoluble but swellable materials. The adhesion of the films towards porcine buccal mucosa decreases with increasing hydroxyethylcellulose content in the blends.     

Compatibility of Bombyx mori chitosan with pectin and Na-carboxymethyl cellulose in solutions

Solutions and blends of Bombyx mori chitosan with pectin and Na-carboxymethyl cellulose were studied by viscometry. The intermolecular interaction parameters and the parameter of the distance of hydrodynamic interaction of a pair of separate molecules were calculated, and the polymer compatibility was assessed.     

Water absorption and degradation characteristics of chitosan-based polyesters and hydroxyapatite composites

Blends of chitosan and biodegradable synthetic aliphatic polyesters (polycaprolactone, poly(butylene succinate), poly[(butylene succinate)-co-adipate], poly[(butylene terephthalate)-co-adipate], and poly(lactic acid)) were injection-molded. These samples were immersed in isotonic solution at 37 degrees C for a period of 60 d. The water uptake and the degradation properties, as measured by the loss in tensile strength, were evaluated as a function of time. In this study, the rate and the equilibrium water uptake were proportional to the amount of chitosan in the blend. The addition of HA to chitosan and polyester significantly reduced the equilibrium water uptake. The water uptake did not follow the classical Fickian phenomena and could be expressed by a two-stage sorption non-Fickian diffusion model. Contact angle measurement was used to quantify the changes in surface hydrophilicity as a function of chitosan and polyester composition. The glycerol contact angle decreased with increasing synthetic components in the blend. The blends and composites also showed increased degradation, as quantified by a loss in their mechanical properties, with increase in natural content. The degradation of properties was directly related to the water uptake of the blends; the higher the water uptake, the higher the degradation. Pure polyesters, while having low water uptake, nevertheless showed significant degradation by a precipitous drop in the strain at break. Among the polyesters, poly(lactic acid) displayed maximum degradation, while polycaprolactone displayed the least.     

Large deformation rheology of gelatin gels

We studied the linear and the non-linear elastic behaviour, the breaking stress and breaking strain of gelatin gels as a function of a number of experimental conditions: gelatin concentration, gelatin bloom value, ageing time, ageing temperature, pH, NaCl and CaCl₂ concentration, whey protein concentration, the amount of pre-shearing, strain rate or compression speed, using both shear deformation and compression. We analyzed the stress-strain curves using the BST-equation (Blatz et al., Trans. Soc. Rheol. 18, (1974) 145) and extracted a parameter that characterizes the linear elastic behaviour at small deformations (the moduli E or G) and one that characterizes the non-linear elastic behaviour at large deformations (the elasticity parameter n). The phenomenological BST equation describes rheological experiments adequately both in shear deformation and in compression.We found that the modulus correlates with the breaking stress. For the non-linear elastic properties of gelatin, we found that the elasticity parameter n correlates with the breaking strain Qualitatively, the non-linear elastic properties can be explained by assuming that the gelatin chains are partially in a crystalline triple helix state (the cross-links) and partially in a random coil state (the network bonds): the more extensive the rigid cross-link regions, the shorter and more stretched the network bonds become as a result of an externally applied deformation. The network bonds behave as anharmonic springs under extreme extension.Manipulation of the breaking strain was attempted in two ways: (i) by changing the (non-linear) elasticity parameter of the gel: this is possible by using a gel that has been further aged; (ii) by adding defects to the gel structure: this is possible by either pre-shearing the gel or by adding whey protein particles. The pre-shearing gives rise to a temporary effect, the addition of whey protein particles to a permanent effect.