Synthesis and Characterization of Starch-Glycidyl Methacrylate-Acrylic Acid Cation Exchange Composites

The synthesis of starch/glycidyl methacrylate/acrylic acid cation exchange composites was achieved by bulk polymerizing of acrylic acid (AA)/glycidyl methacrylate (GMA) mixtures in presence of starch using sodium peroxydisulphate/sodium sulphite initiating redox system. The effect of the concentration of each of sodium peroxydisulphate sodium sulphite, AA and GMA as well as polymerization temperature on the formation of the composites was investigated. Five kinds of composites of different carboxyl contents were prepared and characterized by investigating their potentiometric titrations, durabilities to use, as well as water swellabilities and solubilities.     

改性阳离子交换纤维

研究了对 PAN 纤维的结构进行化学处理制得的改性阳离子交换纤维。红外光谱法分析和端基测定证明了这种纤维具有羧基、螫合结构和吸附金属离子的性质,通过改变pH 值可使纤维再生。测试了吸附量和吸附速率,并讨论了热力学性质。     

Synthesis,Characterization and Properties of Polyacrylamide-Starch Composites

Polyacrylamide-starch composite was prepared by polymerization of maize or rice starch with acrylamide (Aam) using potassium permangante/citric acid initiation system. Major factors affecting the polymerization reaction were studied with a view to discover appropriate conditions for preparation of the composite. Results obtained imply that the total conversion (monomer converted to homopolymer and graft) increases by increasing concentrations of potassium permanganate from 0.5-0.20%, citric acid from 0.1-0.15 and acrylamide from 10-30% ows. Polymerization can easily be carried out at 40°C for 6 min at pH 4 using a material to liquor ratio 1:25 under a stirring rate of 350 rpm. The results further imply (a) that the apparent viscosity of the composite increases by increasing Aam concentration irrespective of the rate of shear, (b) that for 30% Aam concentration the composite consists of 77.7% starch and 22.3% polyacrylamide of which 10.4% are grafted, (c) that the sizeability of polyacrylamide-starch composites is much better than that of native starches, and (d) that the kind of starch not only determines the total conversion but also the composition of the composite.     

Regeneration of a Strong Acid Cation Exchange Resin for Deionizing Corn Syrup Solutions

The influence of regenerant flowrate and concentration on regeneration capacity of cation exchange resins used in refining corn syrups was investigated. A strong acid exchange resin (Duolite C-26®) was examined over a range of resin compositions. Co-current regeneration was modeled using hydrochloric acid at dosages ranging from 64 to 256 g/I (4 – 16 lb/cu. ft.). Resin beds exhausted with large amounts of calcium (and other divalent ions) are best regenerated at high acid concentrations and low regenerant flowrates. Resin beds with large amounts of sodium and/or other monovalent ions are most efficently regenerated at low acid concentrations. Flowrate has little influence on regeneration with large amounts of sodium. Syrup deionized prior to isomerization typically has a lower divalent ion content than syrup deionized after isomerization. This suggests that two separate procedures may be necessary in order to most effectively use the regenerant.     

阳离子交换树脂的硫酸再生

离子交换法除盐在锅炉给水除盐工艺有广泛地应用，目前部分糖厂的糖液澄清工艺也采用离子交换法。由于成本及运输等问题，部分企业采用硫酸再生阳离子交换树脂。本文在总结广西维尼纶集团经验的基础上，对硫酸再生优缺点及其工艺进行讨论，为采用硫酸法再生的企业提供借鉴。     

4,4'-二氨基二苯胺-2-磺酸的合成及其结构表征

本文以2-氯-5-硝基苯磺酸和对苯二胺为原料,通过缩合和还原两步反应,合成了无致癌性染料中间体4,4'-二氨基二苯胺-2-磺酸.利用红外光谱、质谱、氢核磁共振谱对合成产物进行了结构表征.     

对氯甲基苯甲酸链接的莱克多巴胺人工抗原的合成与鉴定

采用对氯甲基苯甲酸(CBA)为链接臂,用混合酸酐法将莱克多巴胺(RAC)与牛血清白蛋白(BSA)偶联制备人工抗原(RAC-CBA-BSA),通过紫外、红外、电泳鉴定抗原合成成功;再以卵清蛋白(OVA)为载体蛋白合成包被抗原(RAC-CBA-OVA),测定其与抗体的亲和力和抑制率。间接竞争ELISA结果以对CBA为链接臂合成的包被抗原对应的抗体滴度为7047.3、IC50为17.05ng/mL,结果表明,CBA可以用于RAC人工抗原的合成,使用RAC-CBA-OVA作为包被抗原可以提高ELISA检测灵敏度。     

Preparation and Characterization of Composites Based on Polylactic Acid and Beeswax with Improved Water Vapor Barrier Properties

Beeswax and a plasticizer (ATBC) were added to polylactic acid (PLA) films in order to enhance the water vapor barrier properties of the films. Beeswax improved the barrier properties; the water vapor permeability in the composite containing 1% beeswax was 58% lower than that of the neat PLA. Fourier transform infrared spectroscopy and X‐ray diffraction analysis revealed that the incorporation of beeswax and ATBC had so little effect on the PLA structure. In addition, the structure of PLA did not vary substantially with the additions. The surfaces of the composites were examined by using field emission scanning electron microscopy. Differential scanning calorimetry results showed that the degree of crystallinity of the PLA films increased with the addition of beeswax and ATBC. However, the tensile strength and elongation at break of the composites containing beeswax were up to approximately 50% lower than those of the neat PLA. Although further study is needed to improve the mechanical properties, the aforementioned results showed that the PLA barrier properties can be improved by the incorporation of a small amount of beeswax and ATBC.     

Lysozyme Separation from Egg White by Cation Exchange Column Chromatography

Cation exchange column chromatography was investigated for simple and efficient separation of lysozyme from homogenized egg white. A macroporus weak acid type resin, Duolite C-464, was selected based on high lysozyme recovery in the90–95% range, retention of whipping and gelling properties in the lysozyme-separated egg white, and ease of column operation. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated high purity of the recovered lysozyme and simultaneous recovery of avidin under the eluting conditions used. The process for lysozyme separation from egg white using Duolite C-464 is suitable for operation in an automated, continuous mode.     

棕榈油脱臭馏出物的阳离子交换树脂催化酯化反应研究

以强酸性阳离子交换树脂为催化剂,经过自制的固定床反应器,使棕榈油脱臭馏出物（PODD）中的脂肪酸与甲醇起酯化反应,合成脂肪酸甲酯.结果表明,酯化反应的最佳物料比为m甲醇/m原料=2;反应温度在甲醇正常沸点以下时,反应温度越高,酯化率越大;酯化率随催化反应时间增大而增大,但增大速度逐渐趋缓.当在常压下,60℃反应56 min时,游离脂肪酸的转化率可达82%左右.结论：用固定床可从PODD连续制备脂肪酸甲酯.     

Fractionation of Lactoperoxidase and Lactoferrin from Bovine Whey Using a Cation Exchange Membrane

A microporous membrane containing immobilized sulfonic acid moieties was used for the rapid fractionation of the cations lactoperoxidase (LP) and lactoferrin (LF) from whey. The breakthrough curves of LP and LF, the LP activity and LF concentration in the elution peaks for different whey loading volumes, and the stability of membrane performance over repeated cycles of loading and elution were measured. Recovery was unaffected by an 8-fold scale-up exercise and repeated cycling, and was 73–6% for LP and 50–5% for LF. The membrane system was more rapid, smaller in size, and used a higher flow rate than traditional bead-based systems.     

生物活性多甲氧基黄酮羧酸和氨基酸衍生物的合成及其结构表征

多甲氧基黄酮(PMFs)是一类存在于柑橘属植物中具有显著抗癌、抗炎和抗氧化等生物活性的天然产物。为了提高多甲氧基黄酮类化合物的水溶性和药用价值,以2种来源丰富且抗癌活性高的多甲氧基黄酮橘皮素和川陈皮素为底物,分别经过氧丙酮氧化得到多甲氧基黄酮醇[3-羟基橘皮素(7)和3-羟基川陈皮素(8)],化合物7和化合物8分别在K₂CO₃和N,N-二甲基甲酰胺条件下与氯乙酸乙酯进行Williamson反应,生成了多甲氧基黄酮羧酸酯类衍生物,再经碱性水解合成了2种未见文献报道的多甲氧基黄酮羧酸衍生物[橘皮素-3-O-乙酸(1)和川陈皮素-3-O-乙酸(2)]。化合物1和化合物2在CH₂Cl₂作溶剂、1-(3-二甲基丙胺)-3-乙基碳二亚胺盐酸盐为缩合剂和4-N,N-二甲氨基吡啶为辅助剂的条件下,分别与2种不同的氨基酸甲酯盐酸盐发生缩合反应,得橘皮素和川陈皮素的氨基酸甲酯衍生物,然后经水解反应得到了4种新型多甲氧基黄酮氨基酸衍生物3～6。对所合成的化合物用¹H NMR、¹³C NMR和MS等方法进行了结构表征。     

不同配体硅胶弱阳离子交换剂的再生与应用

将不同配体的硅胶填料回收酸洗后,以亚氨基二乙酸(IDA)为新配体,分别用直接法和间接法合成IDA-回收硅胶,研究合成填料的色谱性能,并与制备的IDA- 新硅胶色谱柱进行比较。结果表明,尽管IDA- 回收硅胶柱的各项性能均略低于新硅胶色谱柱,但也能有效分离蛋白。用直接法合成得到的IDA- 回收硅胶柱的性能要比用间接法合成得到的IDA- 回收硅胶柱的性能好,并且成功的提取和纯化了蛋清中的溶菌酶(Lys)和猪心中的细胞色素-C(Cyt-C)。研究证明了硅胶回收再利用的可行性。     

从天然紫胶中提取紫胶桐酸的工艺条件

以颗粒紫胶为原料提取紫胶桐酸,在不加入任何有机溶剂的情况下,可获得质量分数>98%的紫胶桐酸产品。研究了皂化时间、皂化化温度、盐析时间、以及亚硫酸钠对紫胶桐酸收率的影响,结果表明:NaOH质量分数25%、料液比(g∶mL)1∶6,皂化时间96h、无水Na2SO3的加入量为紫胶质量的10%,盐析时间18h,紫胶桐酸质量分数可达98.85%~99.43%、收率可达24.64%~25.16%。利用有机元素分析仪、红外光谱方法、显微溶点测定仪对提取的紫胶桐酸结构进行了表征。     

MCC/MOFs抗菌复合材料的制备及表征

采用原位沉积法将两种金属有机框架化合物（Metal-Organic Frameworks,MOFs）MOF-5和1,3,5-均苯三甲酸铜（Ⅱ）（HKUST-1）负载在微晶纤维素（MCC）上,制备出MCC/MOF-5和MCC/HKUST-1二元复合材料以及MCC/MOF-5/HKUST-1和MCC/HKUST- 1/MOF-5三元复合材料;分别采用傅里叶变换红外光谱仪（FT-IR）、X射线衍射仪（XRD）及扫描电子显微镜（SEM）分析复合材料的化学组成和微观形貌;以大肠杆菌（Escherichia coli, E-coli）为测试菌种,通过测定抑菌圈直径检测复合材料的抗菌性能。结果表明,实验成功制备出了表面覆盖有立方体结构的MOF-5和棒状结构的HKUST-1的二元和三元复合材料;由于金属离子的协同抗菌作用,三元复合材料较二元复合材料对大肠杆菌具有更优异的抗菌性能;由于Zn²⁺的抗菌能力大于Cu²⁺,MCC/HKUST-1/MOF-5的抗菌效果较MCC/MOF-5/HKUST-1好。     

强阳离子交换色谱法从牛初乳中分离纯化乳铁蛋白的研究

本实验研究了离子交换色谱技术大规模纯化乳铁蛋白的色谱条件。选用的SP Sepharose Fast Flow离子交换剂对乳铁蛋白有很好的吸附选择性,洗脱速度可达到2L/h。以pH值为7.7～8.0,10mmol/L的磷酸盐为起始缓冲液,通过改变离子强度进行分步洗脱。先采用0.5mol/L的NaCl溶液选择性洗脱分泌型免疫球蛋白A和乳过氧化物酶组分,再采用1mol/L的NaCl洗脱LF组分。经SDS-PAGE测定,所得乳铁蛋白组分显示为单一区带,相对分子质量为80400Da。经等点聚焦测定,所得乳铁蛋白的等电点为8.65。中试生产的精制品中乳铁蛋白的纯度和回收率分别为94.20%和75.45%。     

Fabrication and Characterization of MWCNT Filled Hybrid Natural Fiber Composites

Hybrid composites are fabricated by the combination of two or more fibers using a single matrix. It can be fabricated either with all of its constituents as natural fibers or with one or more constituents belonging to artificial fiber. The stacking sequence of the fibers in a hybrid composite can be altered resulting in a varying mechanical properties. In the present study the MWCNT filled banana-jute-flax fiber reinforced composites are investigated for its mechanical behavior by varying the stacking sequence of the fiber layers and weight % of Multi-Walled Carbon Nano Tube (MWCNT). A Modified resin was prepared by adding MWCNT in the epoxy resin using ultrasonic probe sonicator and a hybrid composite is fabricated with it by using compression moulding processes. The mechanical properties are evaluated as per the ASTM standards. The incorporating of MWCNT and the stacking sequence of fiber layers shows the greater impact on the mechanical properties. The composites of jute fibers at the extremities (JBFBFBFJ) exhibiting the enhancement of tensile, compressive and hardness properties than the flax fiber at the extremities (FBJBJBJF) and it could be used in various automobile applications. Microstructure of the samples are investigated by Scanning Electron Microscope (SEM)with Energy dispersive X-ray (EDS). The results indicate that increasing the weight % of MWCNT and varying the stacking sequence of fibers improves the mechanical properties of hybrid natural fiber composites.     

溶剂交换法制备淀粉纳米颗粒及表征

采用沉淀技术以二甲基亚砜为溶剂,短链醇为不良溶剂利用溶剂交换法制备淀粉纳米颗粒。实验考察了不良溶剂种类,乙醇体积浓度和溶剂/不良溶剂体积比对颗粒尺寸的影响,并对获得的淀粉纳米颗粒结构与形态进行了红外光谱、扫描电镜以及X-射线衍射分析。结果表明:采用无水乙醇为不良溶剂,当溶剂与不良溶剂体积比1∶20情况下,制备的淀粉纳米颗粒尺寸(218.8±4.66)nm,粒子尺寸分布较均匀,化学结构未发生改变,晶体结构被破坏,衍射峰消失。