磺基甜菜碱型PVDF膜在分离洗毛废水中的应用

以甲基丙烯酸二甲氨基乙酯(DMAEMA)和甲基丙烯酸羟乙酯(HEMA)作为共聚单体,采用自由基聚合反应,成功合成了亲水性的无规共聚物poly(DMAEMA-co-HEMA)。将该共聚物添加到聚偏氟乙烯(PVDF)铸膜液中,并通过液致相转化法制备成膜,之后对膜进行后磺化反应,制得磺基甜菜碱型PVDF亲水膜。以羊毛脂乳液作为模拟洗毛废水体系,研究了羊毛脂、表面活性剂SDS质量分数,体系pH值及温度对PVDF亲水膜分离洗毛废水的影响。结果表明,洗毛废水中羊毛脂和表面活性剂十二烷基硫酸钠(SDS)质量分数越高,膜过滤时通量越低,且分离效果也会变差。洗毛废水的pH值应小于7,酸性条件下的分离效果高于碱性条件。洗毛废水温度高于40℃时,分离通量和分离效果都较好。未处理前洗毛废水的COD值为18 120 mg/L,酸沉淀、膜分离后的滤液COD值为2 002 mg/L,COD去除率达89%,通量为917 L/(m~2·h)。     

光交联壳聚糖/聚乙烯醇共混膜的制备与性能

将壳聚糖与感光性物质混合制成感光性壳聚糖 ,再与聚乙烯醇按一定比例共混、成膜并进行光交联 ,制备了系列壳聚糖 (CTS) /聚乙烯醇 (PVA )光交联共混膜 ,并对共混膜的结构和性能进行比较 .结果表明 :重氮树脂系列CTS/PVA光交联共混膜性能优于CTS/PVA共混膜 ,且重氮树脂系列CTS/PVA光交联共混膜有其独特的表面形貌 .孔结构的大小及形态与共混膜中CTS/PVA的比例、重氮树脂的含量有关     

米曲霉发酵液中蛋白动态变化的研究

本文利用葡萄糖和吐温80作为额外碳源培养米曲霉,对其生物量积累,胞链接蛋白以及发酵液蛋白随培养时间的变化情况进行了研究。以葡萄糖作为额外碳源时,米曲霉生物量积累速度较快,在培养24 h已达最大值,为31.97 g/L;当米曲霉以吐温80作为额外碳源时菌体积累较慢,在96 h时达到最大值,为11.15 g/L。发酵液中蛋白总量在以葡萄糖作为额外碳源时比以吐温80时低。以吐温80作为额外碳源时,胞链结蛋白在72 h达到最大值的5.65 mg/g,当以葡萄糖作为额外碳源时,米曲霉胞链结蛋白含量在48 h达到最大值,为1.71 mg/g。利用SDS-PAGE检测192 h内胞连接蛋白质的表达与发酵液中的蛋白质的含量变化与利用lowry法测定的蛋白质含量具有一致的变化趋势:在米曲霉的快速生长期和稳定期时胞链结蛋白种类增加,在衰退期胞链结蛋白种类减少。     

明胶-壳聚糖共混膜的性能研究

利用溶液共混法制备了一系列不同配比的明胶-壳聚糖共混膜,研究了壳聚糖含量对共混膜吸湿性能和力学性能的影响,采用红外光谱、透光率、扫描电镜等表征了共混膜的结构与性能。结果表明:壳聚糖的加入可改善明胶!壳聚糖共混膜的力学性能。随壳聚糖含量的增加,共混膜的吸湿率增大。在共混膜中,壳聚糖分子与明胶分子间存在较强的相互作用,二者间有良好的相容性。     

海水暂养毛钳体内镉脱除工艺研究

目的通过添加壳聚糖、羧甲基壳聚糖、绿茶冲泡液的海水暂养毛钳,探索降低毛钳体内镉含量的方法。方法实验将毛钳随机分为13组,分别暂养于4 L海水中,对照组为海水;壳聚糖浓度分别为0.01、0.05、0.1、0.15 g/L;羧甲基壳聚糖浓度分别为0.01、0.05、0.1、0.15 g/L;绿茶冲泡液浓度分别为25、30、35、40 mL/L。毛钳在13组海水中暂养一定时间后用电感耦合等离子体质谱仪(inductively coupled plasma-mass spectrometer,ICP-MS)测定镉含量。结果使用0.15 g/L壳聚糖、0.15 g/L羧甲基壳聚糖、40 mL/L绿茶冲泡液暂养毛钳18 h时,镉含量从3.128 mg/kg分别降到1.981、1.791、1.830 mg/kg,0~18 h内镉含量都有明显的下降,并且都降到可食用的标准,19~30 h过程中实验组镉含量下降速率减小,30~36 h镉含量几乎保持不变。对照组与其他3组相比毛钳体内的镉含量降低缓慢。结论在暂养海水中添加壳聚糖、羧甲基壳聚糖、绿茶冲泡液均能够有效脱除毛钳体内的镉。     

壳聚糖膜电吸附法去除酱油中铅离子的研究

研究采用壳聚糖膜电吸附法,同时加入钙离子去除酱油中的含铅离子.壳聚糖的湿膜厚度为0.08 mm,膜透水性为0.48 mL·min-1·cm-2.在250 mL酱油中加0.5 mL 浓度为1000 mg/L钙离子,电流15～20 mA,电吸附35 min后,达到最大去除铅的效果,三种不同产地的酱油去除率分别为 87.8%,70.8% 和57.7%,均可达到国家标准.去除铅后,酱油中钙含量比去除前增加1.7%,铜、锌、含量无明显变化,锰降低2.8%,铁降低14.3%,镍降低10%,铬降低33.3%.     

壳聚糖-甘油-丝素共混膜的制备及性能研究

采用流涎法制备壳聚糖-甘油-丝素共混膜,以膜的伸长强度和断裂伸长率为指标,考察各组分混配比例对膜性能的影响.结果显示:壳聚糖可增强膜的拉伸强度,但当壳聚糖浓度≥10 g/L,膜的断裂伸长率出现下降;添加甘油可提高膜的拉伸强度和断裂伸长率;丝素蛋白的添加可使膜的拉伸强度略有上升,同时较明显地提升了断裂伸长率.进一步采用10 g/L壳聚糖、10 g/L甘油、0～20 g/L丝素蛋白成膜,并考察其抑菌性能.结果表明:含5 g/L丝素蛋白的共混膜即可完全抑制金黄色葡萄球菌的生长,含20 g/L丝素蛋白的共混膜可完全抑制大肠杆菌的生长,丝素蛋白的添加大大提高了壳聚糖共混膜的抑菌性能.     

明胶改性壳聚糖膜性能研究

根据壳聚糖与明胶的相容性,制备了壳聚糖膜、壳聚糖/明胶共混膜,研究了增加明胶含量对膜的强度、拉伸位移、溶出率、吸水率的影响.采用FT-IR谱图和XRD谱图分析,研究了膜的微观结构,探讨了共混体系中壳聚糖与明胶的相容性以及分子间的相互作用.当明胶含量在30%时,改性壳聚糖膜的抗拉强度达到最大值;在10%时,它的拉伸断裂伸长达到最大值;20%时,改性膜的吸水率达到最低;改性膜的溶出率则随着明胶含量的增加而增大.     

非水溶性丝素粉体与聚氨酯共混膜的性能

采用浸没沉淀相转化法制备非水溶性丝素粉体与医用聚氨酯共混膜。研究共混膜中非水溶性丝素粉体质量分数不同时共混膜的表面形貌、吸水性、透汽性、水接触角及力学性能和红外光谱图的变化。实验结果表明:随着非水溶性丝素粉体质量分数的增加,共混膜的表面形貌由致密逐渐变得疏松,并逐渐出现微孔,且粉体在共混膜中分布均匀并没有明显的团聚现象,这表明二者的相容性好;另外,共混膜的断裂伸长和拉伸模量较纯PU膜虽有不同程度下降,但其吸水性和透汽性逐渐得到提高;膜的水接触角逐渐下降,表明其亲水性逐步得到提高。     

固定化酵母细胞在酱油中的发酵特性研究

以磁性壳聚糖微球为固定化载体,对固定化酵母细胞的发酵条件进行研究,对影响酵母细胞增殖的主要因素:温度、食盐含量、pH进行分析,以相同时间内还原糖含量为指标,在单因素实验的基础上,利用响应曲面法对反应的发酵条件进行优化。结果表明:固定化酵母细胞最佳条件为温度28.5℃,食盐含量8%,pH6.57,还原糖含量为3.27g/mL。在最佳的发酵条件下应用固定化酵母细胞进行发酵,结果表明其可以有效的增加酱油的香气,提高酱油品质。     

Preparation and properties of rice starch–chitosan blend biodegradable film

Biodegradable blend films from rice starch–chitosan were developed by casting film-solution on leveled trays. The influence of the ratio of starch and chitosan (2:1, 1.5:1, 1:1, and 0.5:1) on the mechanical properties, water barrier properties, and miscibility of biodegradable blend films was investigated. The biodegradable blend film from rice starch–chitosan showed an increase in tensile strength (TS), water vapor permeability (WVP), lighter color and yellowness and a decreasing elongation at the break (E), and film solubility (FS) after incorporation of chitosan. The introduction of chitosan increased the crystalline peak structure of starch film; however, too high chitosan concentration yielded phase separation between starch and chitosan. The amino group band of the chitosan molecule in the FTIR spectrum shifted from 1541.15 cm⁻¹ in the chitosan film to 1621.96 cm⁻¹ in the biodegradable blend films. These results pointed out that there was a molecular miscibility between these two components. The properties of rice starch–chitosan biodegradable blend film and selected biopolymer and synthetic polymer films were compared; the results demonstrated that rice starch–chitosan biodegradable blend film had mechanical properties similar to the other chitosan films. However, the water vapor permeability of rice starch–chitosan biodegradable blend film was characterized by relatively lower water vapor permeability than chitosan films but higher than polyolefin.     

草鱼鱼鳞胶原蛋白-壳聚糖共混膜的制备及其性能研究(续)

以草鱼鱼鳞胶原蛋白和壳聚糖为原料制备共混膜,测定了共混膜的力学性能、水溶液稳定性、水蒸气透过系数、透光率,并用红外光谱、X射线衍射、显微镜等方法表征了共混膜的结构。结果表明:共混膜的最佳组成是1.5%壳聚糖溶液与0.3%胶原蛋白溶液的体积比为1:3。在此条件下形成的共混膜的力学性能、水溶液稳定性、水蒸气透过系数,较单一成分的膜有明显改善,壳聚糖与胶原蛋白之间有强烈的相互作用和良好的相容性,为共混膜在医学材料领域的应用提供试验数据。     

Characterization of quinoa protein–chitosan blend edible films

Quinoa protein/chitosan films were obtained by solution casting of blends of quinoa protein extract (PE) and chitosan (CH). Films from a PE/CH blend were characterized by FTIR, X-ray diffraction, thermal analysis, and SEM. The tensile mechanical, barrier, and sorption properties of the films were also evaluated. The blend of PE with CH yielded mechanically resistant films without the use of a plasticizer. The film had large elongation at break, and its water barrier properties showed that they were more hydrophilic than CH film. The thickness and water-vapor permeability of PE/CH (v/v) 1/1 blend film increased significantly compared to pure CH films. CH films are translucent in appearance and yellowish in blend with PE. By blending anionic PE with cationic CH an interaction between biopolymers was established with different physicochemical properties from those of pure CH. Drying and sorption properties show significant differences between PE/CH blend film and CH film. The structural properties determined by XRD, FTIR and TGA showed a clear interaction between quinoa proteins and CH, forming a new material with enhanced mechanical properties.     

壳聚糖/羟丙基纤维素共混材料的流变学与润湿性

探讨壳聚糖/羟丙基纤维素（HPC）共混材料的流变性与润湿力。使用RVDV-ⅡPRO黏度计测定体系的黏度和剪切应力以考察组成与温度对材料流变性的影响;借助K100表面张力仪测定膜的接触角以考察材料的润湿力。结果显示：除壳聚糖与HPC质量分数均≤1%的共混溶液近似为牛顿流体外,其余均为非牛顿流体;溶液黏度随温度升高而降低;20℃时共混膜的润湿力为甲醇＞DMF＞乙二醇＞水;膜最低水接触角依次为20℃＜40℃＜30℃;弱酸或弱碱性介质均可提高膜的亲水性;当HPC质量分数为0～1%时,水接触角由空白值71.04°最低可降至55.38°。该结果对壳聚糖/HPC共混材料的纺丝与应用有指导作用。     

胶原蛋白-壳聚糖-聚乙烯吡咯烷酮共混膜的结构及性能

利用溶液共混法成功制备了新型生物膜材料--胶原蛋白-壳聚糖-聚乙烯吡咯烷酮共混膜,通过红外光谱、X-射线衍射和透光率测试表征了共混膜的结构,同时测定了共混膜的力学性能,考察了溶液pH值对共混膜吸水率的影响.结果表明共混膜中胶原蛋白、壳聚糖和聚乙烯吡咯烷酮三者具有较强的相互作用和良好的相容性.共混膜具有良好的力学性能,一定pH敏感性,作为一种潜在的生物材料可望在生物医学领域得到应用.     

Characterization of chitosan–whey protein films at acid pH

The capability to produce blend chitosan–whey protein films at acidic pH, carrying a high amount of protein, is demonstrated, even though under these conditions a pure whey protein film could not be obtained. The films are biphasic and characterized by a compositional gradient, with the downward film surface containing a lower amount of protein than the upward surface. The surface richer in protein was more hydrophobic than that richer in chitosan. The difference in composition and hydrophilicity between both surfaces increases with the amount of protein incorporated in the film. Increasing the protein amount decreased elongation at break and tensile strength but, in general, had little effect on water vapor permeability. Although some of the film functionality might be compromised due to the incompatibility between the polysaccharide and protein components within the film matrix, the blended films, especially those with intermediated protein amount, may have useful applications on those food systems where the edible films should break up during the cooking or mastication process.     

改性扇贝壳粉与壳聚糖复合膜的制备及性质研究

以扇贝壳为原料,硬脂酸钠为改性剂,通过湿法改性制备了改性扇贝壳粉。采用单因素和响应面试验探讨改性温度、改性剂用量、改性时间对扇贝壳粉改性效果的影响,利用傅里叶红外光谱仪、电子扫描电镜和X射线衍射仪对扇贝壳粉进行表征。将制成的改性扇贝壳粉与壳聚糖制成复合膜,考察改性扇贝壳粉质量分数对复合膜性质的影响。结果表明,扇贝壳粉最佳改性条件为:硬脂酸钠添加量2.53%,改性温度80.70 ℃,改性时间43.19 min,在此条件下制得的扇贝壳粉活化度最高可达到76.41%,结合表征图谱分析,硬脂酸钠成功结合到壳粉表面,壳粉粉体粒子间团聚作用减弱,制得的改性扇贝壳粉具有良好的分散性。添加改性扇贝壳粉可以有效提高壳聚糖膜的机械性能、透光性和水蒸气阻隔性能。当改性扇贝壳粉的质量分数为1%时,改性扇贝壳粉与壳聚糖复合膜的性能最佳,此时膜拉伸强度为30.19 MPa,断裂伸长率为10.2%,水蒸气透过量为35.1 g·h?1·m?2,透光性为2.9 mm·%。