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载脂肪酶壳聚糖/海藻酸钙微胶囊的制备 总被引:1,自引:0,他引:1
针对固定化脂肪酶的研究背景,以壳聚糖、海藻酸钠为微载体制备材料,采用脉冲电场液滴工艺制备壳聚糖/海藻酸钙微胶囊。以脂肪酶为生物模型,系统考察了制备条件对载脂肪酶壳聚糖/海藻酸钙微胶囊酶活力的影响。结果表明:海藻酸钠质量浓度和酶与海藻酸钠载体配比是影响固定化酶活力的主要因素,载酶量为15mg/mL,海藻酸钠质量浓度为10mg/mL时载酶微胶囊酶活力最高,球形度好。通过改变壳聚糖质量浓度和相对分子质量,可以调控微胶囊膜的厚密程度进而影响固定化酶活力。成膜液pH值依次影响壳聚糖与海藻酸盐分子中官能团的电离状态、成膜反应静电络合程度、酶蛋白包封率,最终影响固定化酶活力。在载酶量为15mg/mL,海藻酸钠质量浓度为10mg/mL,壳聚糖相对分子质量、质量浓度和pH值依次为50kDa、1mg/mL和3.0的条件下,固定化酶活力为187IU/g。 相似文献
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为提高涤纶织物的阻燃性能,并解决涤纶织物的熔滴现象,本文采用石墨烯微胶囊与海藻酸钠共混制备出阻燃涂覆液,采用浸轧法制备阻燃涂覆涤纶织物。考察涂覆涤纶织物的阻燃性能,力学性能以及热学性能,结果表明:25g/L的海藻酸钠和1g的石墨烯微胶囊阻燃涂覆处理后的涤纶织物的极限氧指数由19.7%,上升到28.34%,达到难燃织物的标准。整理后的涤纶织物达到了V-0标准,涤纶织物燃烧后产生的熔滴的现象消失。织物的断裂强力由135.21N降低到了106.77N。涂覆处理前后,织物达到最大热分解速率的温度未产生明显变化,残炭率由12.07%上升到了26.98%,最大质量损失速率由1.79%/℃降低到了0.96%/℃。同时整理前后涤纶织物的热焓值由58.4J/g上升至68.4J/g。织物的导热系数由0.587 W/cm.℃×10-4提高到0.842W/cm.℃×10-4,热学性能得到了充分的提高。织物燃烧后所形成的残炭由无到连续且致密。 相似文献
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海藻酸钙/聚精氨酸微胶囊的载药和缓释性能 总被引:1,自引:0,他引:1
采用乳化-固化法,制备海藻酸钙/聚精氨酸微胶囊。分别考察不同聚精氨酸相对分子质量、海藻酸钠浓度、氯化钙浓度对海藻酸钙-聚精氨酸微胶囊载药量以及牛血红蛋白缓释性能的影响。实验结果表明,中相对分子质量聚精氨酸制备的海藻酸钙/聚精氨微胶囊的载药量较高并且具有更好的缓释效果。随着海藻酸钠浓度的升高,海藻酸钙/聚精氨微胶囊的载药量降低;随着氯化钙浓度的升高,海藻酸钙/聚精氨微胶囊的载药量先升高后略有降低;然而,以上因素对海藻酸钙/聚精氨微胶囊的缓释性能均无明显影响。 相似文献
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为解决聚电解质壳聚糖与海藻酸钠混合溶液相反电荷团聚,采用核壳喷丝头,将添加氯化钙的壳聚糖混合纺丝液和海藻酸钠纺丝液经喷丝头的壳层、核心分别喷出后,然后两种溶液之间发生缓慢的离子键络合,海藻酸钠在氯化钙作用下,缓慢变为海藻酸钙,并在重力作用下牵伸,得到结构均匀致密的复合单丝。通过对复合单丝结构、性能分析表明,2%壳聚糖溶液中氯化钙溶液添加量为壳聚糖溶液质量的7%,1.5%海藻酸钠溶液,复合单丝的强力达到1.14 cN/dtex,较未加入氯化钙的复合单丝提高了55.4%,在水中浸泡1 h后的溶胀比达到33.2,表明该复合单丝制作的敷料保水性能好,具有较好的应用前景。 相似文献
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含微胶囊相变材料的海藻酸钙大胶囊的制备及其性能 总被引:2,自引:1,他引:1
采用原位聚合法合成了微胶囊相变材料,并通过锐孔法制备了海藻酸钙包覆多个微胶囊相变材料的大胶囊。用FTIR分析了大胶囊的化学结构,采用游标卡尺测量在不同质量分数的海藻酸钠水溶液和氯化钙水溶液中制备的大胶囊的平均粒径;用SEM和DSC对微胶囊相变材料的微观形貌和热性能进行了分析,对大胶囊的热性能进行了考察,讨论了在不同海藻酸钠质量分数下制备的大胶囊经甲苯萃取30 m in后的热性能。结果表明,微胶囊呈粒径均一,表面光滑,密封较好的球体;其相变温度为34.1℃,相变潜热为143.8 J/g。随着微胶囊相变材料加入量的增加,大胶囊的相变潜热逐渐增加;当w(CaC l2)=2%时,随着海藻酸钠质量分数的增加,大胶囊的粒径由1.36 mm逐渐增加至1.96 mm并趋于平缓,且海藻酸钠水溶液质量分数不宜超过3%;随着氯化钙质量分数的增加,大胶囊平均粒径逐渐增长,但幅度较其随海藻酸钠质量分数变化的幅度小;甲苯对大胶囊壳材的渗透能力随海藻酸钠质量分数的增加而减小。 相似文献
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Wei Zhao Ying Zhang Yang Liu Mingqian Tan Weiting Yu Hongguo Xie Ying Ma Guangwei Sun Guojun Lv Shan Zhao Xiaojun Ma 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(3):449-455
BACKGROUND: Oxygen diffusion properties affect the proliferation and metabolism of cells cultured in microcapsules with a polyelectrolyte complex membrane. The effective diffusion coefficient (De) of oxygen in alginate/chitosan (AC) microcapsules under different preparation conditions was calculated, and a mathematic model was developed to investigate the effect of oxygen diffusion on cell loading in the microcapsules. RESULTS: Oxygen De in AC microcapsules was independent of alginate solution concentration, intrinsic viscosity of alginate and different polyelectrolyte complex membranes. De decreased from 2.1 ± 0.3 × 10?9 to 0.17 ± 0.01 × 10?9 m2 s?1 as microcapsule diameter decreased from 1800 to 45 0 µm. Microcapsule density was increased from 1.013 ± 0.000 to 1.034 ± 0.003 g mL?1 as diameter decreased from 1775 to 430 µm. The mathematic model results showed that critical CHO cell loadings were 1.8 × 108 or 1.1 × 108 cells mL?1 in microcapsules with 450 or 1800 µm diameter, respectively. CONCLUSIONS: No significant difference was found of oxygen De between calcium alginate beads and AC microcapsules. The decrease of De with diameter was attributed to the increasing density and compact degree on the surface. The model results indicated that risk on necrosis rose with the increasing diameter. Microcapsules with smaller diameters may have more advantages on cell culture. © 2012 Society of Chemical Industry 相似文献
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Chitosan, a cationic polysaccharide, was heterogeneously deacetylated with a 47% sodium hydroxide solution and followed by a homogeneous reacetylation with acetic anhydrides to control the N-acetyl content of the chitosan having a similar molecular weight. The chitosans having different degrees of N-acetylation were complexed with sodium alginate, an anionic polysaccharide, and the formation behavior of polyelectrolyte complexes (PECs) was examined by the viscometry in various pH ranges. The maximum mixing ratio (Rmax) increased with a decrease in the degree of N-acetylation of the chitosan at the same pH, and with a decrease in pH at the same degree of N-acetylation. Similarly, N-acylated chitosans were also prepared. The N-acyl chitosans scarcely affected the formation behavior of PECs with sodium alginates. For the application of the PECs produced, the microencapsulation of a drug was performed and the release property of drug was tested. The microcapsules were prepared in one step by the extrusion of a solution of guaifenesin and sodium alginate into a solution containing calcium chloride and chitosan through interpolymeric ionic interactions. The drug release during the drug-loaded microcapsules storage in saline was found to depend on the pH where the microcapsules were formed and the kind of N-acyl groups introduced to the chitosan. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 425–432, 1997 相似文献
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A mild chitosan/calcium alginate encapsulation process, as applied to encapsulation of hemoglobin, was investigated. The first procedure consisted of adding dropwise a hemoglobin-containing sodium alginate mixture in a chitosan solution, then hardening the interior of capsules thus formed, in the presence of CaCl2. In the second method, the droplets were directly pulled off in a chitosan–CaCl2 mixture. Both procedures led to beads containing a high concentration in entrapped hemoglobin as more than 90% of the initial concentration (150 g/L) were retained inside the beads provided that the chitosan concentration was great enough. The molecular weight of chitosan (M?u 245,000 or 390,000) and the pH of its solution (2, 4, or 5.4) had only a slight effect, the best retention being obtained with beads prepared at pH 5.4. The hemoglobin release during the bead storage in water was found to depend on the conditions of their formation and especially on the chitosan molecular weight. The best retention during storage in water was obtained with beads prepared with the high M?u chitosan solution at pH 2. Considering the total loss in hemoglobin during the bead formation and after 1 month of storage in water, the best results were obtained by preparing the beads in an 8 g/L solution of a 390,000 chitosan at pH 4 (less than 7% of loss with regard to the 150 mg/L initial concentration). © 1994 John Wiley & Sons, Inc. 相似文献
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