酶解褐藻胶寡糖的吸湿及保湿性能研究

以海藻酸钠为底物,在实验室自制的褐藻胶裂解酶的催化下,通过控制酶解时间,得到平均聚合度(DP)分别为3,4,6的3种褐藻胶寡糖DP3,DP4,DP6。通过干燥器控制湿度的方法对产物进行吸湿和保湿性能测试,并和化妆品常用保湿剂丙三醇、聚乙二醇600(PEG600)及原料海藻酸钠进行比较。结果表明,在0～64 h内,在相对湿度(RH)为43%的环境中的吸湿率大小为:DP3>丙三醇>DP4>DP6>PEG600>海藻酸钠;在RH为81%的环境中的吸湿率大小为:丙三醇>DP3>DP4>DP6>PEG600>海藻酸钠;在硅胶环境中保湿能力大小为:DP3>DP4>DP6>丙三醇>PEG600>海藻酸钠。64 h时DP3在RH为43%和81%环境下的吸湿率分别为66.4%和108.9%,在硅胶环境中的保湿率为46.1%。DP3表现出优良的吸湿和保湿性能,是一种很有开发潜力的天然保湿剂。     

表面活性剂对氯酸钠晶体防结块性能的影响

用在氯酸钠饱和溶液中添加表面活性剂和氯酸钠晶体进行表面处理的方法，制备得到了一系列表面改性氯酸钠晶体试样；并分别用吸湿性试验和加压加湿强化结块试验对试样进行防吸湿性能和防结块性能定量测试研究。发现试样的吸湿率与时间之间呈现出很好的线性关系，并确定出试样的吸湿速度常数。提出了分别用试样的吸湿速度常数和最大破碎压力计算相对于参比试样的防吸湿率和防结块率方法，讨论了防结块剂配方对氯酸钠晶体的防吸湿性能和防结块性能的影响。确定出烷基苯磺酸钠为氯酸钠晶体较为合适的防结块添加剂，其质量分数为0．01％～0．08％。     

几种天然多糖的吸湿和保湿性能的初步研究

通过干燥器控制湿度的方法对魔芋葡甘聚糖、羧甲基纤维素钠、壳聚糖、海藻酸钠等多糖与常用保湿剂甘油进行了吸湿和保湿性能测试.结果表明,在高相对湿度条件下,各试样的吸湿能力依次为:羧甲基纤维素钠＞甘油＞海藻酸钠＞魔芋萄甘聚糖＞壳聚糖;在低相对湿度条件下,各试样的吸湿能力依次为:甘油＞羧甲基纤维素钠＞海藻酸钠＞魔芋葡甘聚糖＞壳聚糖.各试样的保湿能力依次为:壳聚糖＞魔芋葡甘聚糖＞海藻酸钠＞甘油＞羧甲基纤维素钠.此外,采用热重分析法(TGA)对各试样的失重率进行了测试,其失重曲线与保湿曲线趋势一致.     

硼酰化钴的吸湿性及其对胶料粘合性能的影响

介绍硼酰化钴的特殊分子结构及其吸湿性原理,分析环境温度、相对湿度和吸湿时间对硼酰化钴吸湿性能的影响。结果表明,相同条件下,环境温度越高、相对湿度越大、吸湿时间越长,硼酰化钴的吸湿程度越大,胶料的粘合性能下降越明显。     

亚甲基二甲胺盐酸盐淀粉醚的制备及其吸湿保湿性能研究

以淀粉为母体,羟甲基二甲胺盐酸盐(HMMAHC)为醚化剂,通过干法工艺合成出不同取代度(DS)的叔胺型阳离子淀粉——亚甲基二甲胺盐酸盐淀粉醚(SMMAHC),并考察了其吸湿、保湿性能。结果表明,该阳离子淀粉的吸湿、保湿性能均随着阳离子基团取代度的增加而增强。在相对湿度(RH)为81%的条件下,当阳离子取代度分别为0.36和0.70时,其吸湿性分别与透明质酸(HA)和丙三醇相当。而取代度为0.70的SMMAHC保湿性在相对湿度43%和15%下均与透明质酸相当,优于丙三醇。探讨了SMMAHC吸湿动力学,可应用伪二级吸附动力学模拟方程很好地描述吸湿性能,相关系数达到0.999以上。     

壳聚糖季铵盐的吸湿、保湿性能研究

采用以异丙醇为溶剂,以3-氯-2-羟丙基三甲基氯化铵(CTA)为改性剂,在碱性条件下制备了水溶性壳聚糖季铵盐。对其进行了吸湿、保湿性能的测试。壳聚糖季铵盐在相对湿度为43%的干燥器中放置48h吸湿率可达28.6%,水分残存率可达170.5%;在相对湿度为81%的干燥器中放置48h吸湿率可达54.2%,水分残存率可达615.2%;在硅胶干燥器中放置48h水分残存率可达82.4%。壳聚糖季铵盐的吸湿、保湿性能均优于同等条件下透明质酸的测定结果。     

昆布氨酸的吸湿保湿性及动力学研究

通过将自制的昆布氨酸与原料L-赖氨酸盐酸盐以及甘油和透明质酸进行对比,对昆布氨酸的吸湿性能和保湿性能进行了研究,并对其吸湿过程作了初步的动力学分析。结果表明:昆布氨酸在相对湿度43%时的最大吸湿率为43.7%,保湿率为100.7%;在相对湿度81%时的最大吸湿率为85.1%,保湿率为103.8%;其吸湿性和保湿性均优于L-赖氨酸盐酸盐、甘油和透明质酸;昆布氨酸的吸湿过程符合二级吸附动力学模型,相关系数达到0.99以上。     

葡萄皮提取物/壳聚糖/塔拉胶抗氧化膜的制备及表征

本实验将葡萄皮提取物与塔拉胶/壳聚糖共混制备膜材料,研究不同葡萄皮提取物添加量对复合膜的力学性能、色度、透光性能以及抗氧化性能的影响。结果表明随着提取物添加量的增加,膜材料的拉伸强度从38 Mpa下降至8 Mpa,膜材料的透光性能降低;但是随着其含量的增加,抗氧化性能逐渐增加,当添加量为20%时,膜材料对DPPH的去除率高达39.5%。因此,该膜材料在抗氧化包装膜材料有潜在的应用前景。     

壳聚糖及其衍生物的制备和保湿吸湿性能评价

简要介绍了壳聚糖及其衍生物的制备方法和物化性质。以甘油、山梨醇和透明质酸为参照物，在一定相对湿度下考察了壳聚糖、羧甲基壳聚糖、N—羧丁基壳聚糖等几种保湿剂的保湿吸湿性能。结果显示，羧甲基壳聚糖和N—羧丁基壳聚糖的保湿吸湿性能最优，完全可以替代透明质酸，作为多种化妆品的保湿剂。     

沉淀白炭黑吸湿特性及动力学、热力学分析

白炭黑是一种重要的吸附材料,以沉淀白炭黑为原料,研究了沉淀白炭黑在温度为15℃、20℃、25℃和30℃,相对湿度为11%、33%、43%、75%、85%和98%条件下的吸湿性能,并进行吸湿动力学分析。利用多孔介质等温吸附热力学原理,计算沉淀白炭黑的等温吸附热。结合XRD、SEM、FTIR和氮吸附法分析沉淀白炭黑的吸湿机理。结果表明:沉淀白炭黑具有良好的吸湿性能,在温度为30℃、相对湿度为98%时48h吸湿量达到23.71%。相对湿度在11%~85%范围内,温度越低、相对湿度越高,沉淀白炭黑的吸湿性能越强;相对湿度为98%时,温度越高,沉淀白炭黑的吸湿性能越强。沉淀白炭黑的吸湿动力学符合准二级动力学模型。等温吸湿曲线符合典型的可冷凝蒸汽在孔隙物质中物理吸附的S型曲线,水分子与沉淀白炭黑之间的作用力主要为范德华力和氢键作用。     

Bio‐hybrid nanocomposite coatings from sonicated chitosan and nanoclay

Nanocomposite films and coatings with improved properties were produced from ultrasonic dispersed chitosan and hydrophilic bentonite nanoclay. Bio‐hybrid coatings were applied onto argon–plasma‐activated LDPE coated paper. The intercalation of chitosan in the silicate layers was confirmed by the decrease of diffraction angles as the chitosan/nanoclay ratio increased. Nanocomposite films and multilayer coatings had improved barrier properties against oxygen, water vapor, grease, and UV‐light transmission. Oxygen transmission was significantly reduced under all humidity conditions. In dry conditions, over 99% reduction and at 80% relative humidity almost 75% reduction in oxygen transmission rates was obtained. Hydrophilic chitosan was lacking the capability of preventing water vapor transmission, thus total barrier effect of nanoclay containing films was not more than 15% as compared with pure chitosan. Because to very thin coatings (≤1 μm), nanoclay containing chitosan did not have antimicrobial activity against test strains. All coating raw materials were “generally recognized as safe” (GRAS) and the calculated total migration was in all cases ≤6 mg/dm², thus the coatings met the requirements set by the packaging legislation. Processing of the developed bio‐hybrid nanocomposite coated materials was safe as the amounts of released particles under rubbing conditions were comparable with the particle concentrations in a normal office environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Nanofiltration membranes based on poly(vinyl alcohol) and ionic polymers

Nanofiltration membranes based on poly(vinyl alcohol) (PVA) and ionic polymers, such as sodium alginate (SA) and chitosan, were prepared by casting the respective polymer solutions. The membranes prepared from PVA or PVA–ionic polymer blend were crosslinked in a isopropanol solution using glutaraldehyde as a crosslinking agent. The membranes were characterized with Fourier transform infrared spectroscopy and X‐ray diffractometry and swelling test. The membranes crosslinked through the acetal linkage formation between the  OH groups of PVA and the ionomer and glutaraldehyde appeared to be semicrystalline. To study the permeation properties, the membranes were tested with various feed solutions [sodium sulfate, sodium chloride, poly(ethylene glycol) with 600 g/mol of molecular weight (PEG 600), and isopropyl alcohol]. For example, the permeance and the solute rejection of the 1000 ppm sodium sulfate at 600 psi of upstream pressure through the PVA membrane were 0.55 m³/m² day and over 99%, respectively. The effects of the ionomers on the permeation properties of the PVA membranes were studied using the PVA–SA and PVA–chitosan blend membranes. The addition of small amount of ionic polymers (5 wt %) made the PVA membranes more effective for the organic solute rejection without decrease in their fluxes. The rejection ratios of the PEG 600 and isopropanol were increased substantially. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1755–1762, 1999     

Permeation of molecules through different polymeric membranes

Permeation of molecules through the membranes plays an important role in immobilized cell systems. Permeation of molecules like glucose and bovine albumin serum was studied through chitosan, polyvinyl alcohol, and polyvinyl acetate membranes using a flow cell made of two detachable compartments. Permeation of molecules through chitosan, polyvinyl alcohol, and polyvinyl acetate membranes increases with decrease in hydrophobic characteristics of the membrane. Permeation of molecules also show its dependency on the molecular weight of the solute. Distribution coefficient of glucose and bovine serum albumin in these polymeric membranes measured by equilibration technique indicates that permeation of molecules through these membranes follows pore type mechanism. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3469–3472, 1999     

纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜性能与细胞相容性

以椰壳纤维为原料,制备了纳米纤维素晶须,用硅烷偶联剂对纳米纤维素晶须进行改性,将改性后纳米纤维素晶须与壳聚糖、聚乙烯醇共混,采用溶液浇铸法制备了改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜。采用FTIR、DSC、TG、XRD和SEM对改性纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜的结构、热性能、结晶行为和形貌进行表征与分析,对复合膜的力学性能和水接触角进行测试,将成纤维细胞L929接种到复合膜上,对其进行细胞相容性实验。结果表明,添加改性纤维素晶须,能够使壳聚糖/聚乙烯醇复合膜的热性能、结晶行为和力学性能提高,成纤维细胞在复合膜上具有较好的黏附和生长,制备的纳米纤维素晶须-壳聚糖/聚乙烯醇复合膜具有良好的综合性能和细胞相容性。     

Influence of the coagulation medium on the performance of poly(ether sulfone) flat‐sheet membranes

Poly(ether sulfone) flat‐sheet membranes were fabricated via phase inversion with different nonsolvent mixtures. The effect of the nonsolvent water with the addition of various amounts of ethanol, acetone, or isopropyl alcohol on the membrane morphology (as measured with scanning electron microscopy and atomic force microscopy) and the filtration performance were investigated. For the statistical evaluation of the fabrication process, on average, six membranes were produced. The pure water flux (PWF) and macromolecule retention were determined via filtration experiments. The presence of coagulation additives resulted in modified precipitation kinetics and thermodynamics, yielded different membrane structures, and therefore, influenced the performance. The results show that the addition of ethanol, acetone, and isopropyl alcohol in low concentrations (up to 10%) to water led to an increasing PWF. Higher concentrations led to a decrease in PWF. For high concentrations (>30%), a change in the membrane morphology from fingerlike to spongelike structures was expected, and this was experimentally proven for the case of ethanol. One main finding was the similarity of the influence of the used additives on the membrane performance. This was to be expected from Flory–Huggins theory for additives with high water miscibility; hence, under these circumstances, entropic and not energetic reasoning dominated the phase‐inversion process. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41645.     

Effects of polysaccharides on the properties of Chinese lacquer sap

Raw lacquer sap was modified by the addition of small amounts of 2 wt% polysaccharide (lacquer polysaccharide, chitosan, carboxymethyl cellulose and sodium alginate) aqueous solution. The polysaccharide-modified lacquer saps dried faster than raw lacquer sap at a high relative humidity of 80%. The drying property strongly depended on the structure of polysaccharides and the drying time was in the order of chitosan < carboxymethyl cellulose < sodium alginate < lacquer polysaccharide. All lacquer saps did not dry at a very low relative humidity of 16%. However, when the relative humidity was adjusted to 70%, the polysaccharide-modified lacquer saps dried, while the raw lacquer sap did not. This difference was probably due to stronger hydrophilicity of polysaccharide-modified lacquer films’ surfaces. In addition, the addition of polysaccharides greatly improved the gloss of lacquer films, but had little effects on the thermal, mechanical and chemical resistance properties of lacquer films.     

陶瓷坯体增强剂聚丙烯酸钠在艺术瓷成形过程的应用

本文合成了一系列不同相对分子质量的聚丙烯酸钠,应用于艺术瓷的坯体中,研究了聚丙烯酸钠对艺术瓷坯体强度、变形率的影响,并对聚丙烯酸钠增强机理进行了探讨。结果表明:聚丙烯酸钠可有效地提高艺术瓷坯体的成形强度,减少了坯体的变形率,当增强剂c加入的质量分数为0.6%时,坯体的干燥强度增加率达167.5%,坯体的变形率从50%降低到10%。     

Investigations on nylon 4 membranes: Synthesis and transport properties. II. Transport properties of nylon 4 polymer membranes

The reverse osmosis, ultrafiltration, and dialysis properties of nylon 4 membranes to separations of sodium chloride, urea, a series of ethylene glycols and other compounds in the aqueous phase were investigated. The nylon 4 membranes were prepared from a formic acid solution with and without organic or inorganic additives. The effects of polymer concentration, amount of additives, casting time, and temperature on the membrane performance in terms of salt separation and product rate were investigated. The tensile properties of the nylon 4 membranes in both the dry and wet states were determined. It was found that the highest salt separation of a 0.1% sodium chloride solution did not exceed 53.3%. However, these membranes showed some intersting dialysis properties which were comparable to those of commercial cellophane and cellulose acetate membranes.     

Pervaporation separation of sodium alginate/chitosan polyelectrolyte complex composite membranes for the separation of water/alcohol mixtures: Characterization of the permeation behavior with molecular modeling techniques

Polyelectrolyte complex (PEC) membranes were prepared by the complexation of protonated chitosan with sodium alginate doped on a porous, polysulfone‐supporting membrane. The pervaporation characteristics of the membranes were investigated with various alcohol/water mixtures. The physicochemical properties of the permeant molecules and polyion complex membranes were determined with molecular modeling methods, and the data from these methods were used to explain the permeation of water and alcohol molecules through the PEC membranes. The experimental results showed that the prepared PEC membranes had an excellent pervaporation performance in most aqueous alcohol solutions and that the selectivity and permeability of the membranes depended on the molecular size, polarity, and hydrophilicity of the permeant alcohols. However, the aqueous methanol solutions showed a permeation behavior different from that of the other alcohol solutions. Methanol permeated the prepared PEC membranes more easily than water even though water molecules have stronger polarity and are smaller than methanol molecules. The experimental results are discussed from the point of view of the physical properties of the permeant molecules and the membranes in the permeation state. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2634–2641, 2007     

Studies of syntheses and permeabilities of special polymer membranes

Summary A new method of enzyme immobilization by a polyion complex was proposed. An enzyme immobilizing membrane was prepared by ultrafiltrating a mixture consisted of quarternized chitosan, sodium polyacrylate and invertase in an aqueous NaBr solution. The permeation and hydrolysis characteristics of aqueous sucrose solution through the invertase immobilizing membrane was studied under some conditions. A hydrolysis rate of sucrose by the invertase immobilizing membrane corresponded to the Michael is-Menten type reaction.