Preparation and Characterization of Anion-Exchange Starches

Treatment of poly (glycidyl methacrylate (GMA))-starch graft copolymer containing 270 m.eq.epoxy groups/100 g sample with ethylenediamine was carried out under different conditions. Results indicated that three reactions are likely to occur during this treatment, namely amination, crosslinking and hydrolysis. The highest amine content could be achieved upon using amine/epoxy molar ration of 2.5 and material to liquor ratio 1:3, at 90°C for 180 min. The dependence of the amination percent on the type and nature of the amine was also studied. The values of amination percent for the different types of amine follows the order: O-phenylene-diamine > m-phenylenediamine > p-phenylenediamine > ethylenediamine; whereas studying the nature of the amine brings about the order: diethylamine derivative > ethylamine derivative > ethanolamine derivative > triethylamine derivative. Evaluation of the different reaction products (aminated copolymers) for their anion exchange properties was made. The capacity of the anion exchangers relied on the inital epoxy content of the copolymer and type and nature of the amine used. On the other hand, heavy metal anions and dye removal efficiency followed the order: diethylamine derivative > ethylenediamine derivative > triethylamine derivative > p-phenylenediamine > derivative > ethylamine derivative. The pH-metric titration curves revealed that triethylamine derivative behaves as a strong base while the other exchangers as weak bases. Other properties such as pK_b value, durability, solubility, etc. indicated that the synthesized products can be regarded as anion exchangers with acceptable properties.     

不同原料辛烯基琥珀酸淀粉酯的制备及糊性质的研究

以糯玉米淀粉、早籼米淀粉、小麦淀粉和马铃薯淀粉为原料,采用湿法工艺制备辛烯基琥珀酸淀粉酯,并对所制备不同取代度产品的糊性质进行了研究.结果表明,4种淀粉的酯化反应效率为:早籼米淀粉>糯玉米淀粉>马铃薯淀粉>小麦淀粉.黏度速测仪(RVA)分析显示,几种淀粉经辛烯基琥珀酸酐(0sA)改性之后.具有较原淀粉高的峰值黏度.随着取代度的增加,糯玉米淀粉、早籼米淀粉和小麦淀粉的透明度提高,但是马铃薯淀粉糊的透明度却降低.经过OSA改性之后,糯玉米淀粉、早籼米淀粉、小麦淀粉和马铃薯淀粉糊的凝沉性都明显降低,并且随着改性程度的提高,析出水的体积逐渐减少.     

Preparation and Characterization of Some Cationic Starches

Three types of cationic starches were prepared via reacting starch with 3-chloro-2-hydroxypropyl amine, 1,1,1,n-Tris(3-chloro-2-hydroxypropyl) amine and glycidyl trimethyl ammonium acetate in presence of sodium hydroxide. The different factors affecting these reactions were investigated. These factors include sodium hydroxide/amine, amine/starch molar ratios, liquor ratio, reaction duration and temperature. The amination extent and amination reaction efficiency percent were traced by estimating the nitrogen content of the aminated starch. Characterization of the prepared cationic starches such as solubility, moisture content, anion-exchange capacity and metal ions sorption were studied.     

Morphology of Cereal Starches Grafted with Polyacrylonitrile

Morphological aspects of six cereal starches and their graft copolymers with polyacrylonitriles (PAN) prepared from granular as well as geletinized starches are reported. Scanning electron microscopy showed that grafting is not uniform on the surface but has also occurred in the interior of the granules. The graft copolymers prepared from gelatinized starches maintained the individuality but no resemblance with original shape of the granules.     

Preparation and Characterization of Cationexchange Starches Containing Carboxyl Groups

Rice starch was first crosslinked using epichlorohydrin. The crosslinked starch was then subjected independently, to graft polymerization with acrylonitrile (AN) and cyanoethylation reactions. The poly (AN)-starch graft copolymer and the cyanoethyl starch so obtained were treated with sodium hydroxide to effect conversion of the cyanide groups of the modified starches into carboxyl groups via alkaline hydrolysis. It was found that the alkaline treatment results in decrement in the nitrogen content and increment in the carboxyl content. The magnitude of both contents is determined by sodium hydroxide concentration as well as duration and temperature of the treatment. It was also found that beside conversion of the cyanide groups to carboxyl groups, alkaline hydrolysis brings about cleavage of ether linkage of the copolymer and the cyanoethyl starch. This was evidenced by large difference observed between the sum of the substituents before and after hydrolysis. In this regard, cleavage of the ether linkage is greater with cyanoethyl starch than the poly (AN)-starch graft copolymer. The potential value of the hydrolyzed modified starches to serve as cation exchanger was assessed through measurements of critical properties such as durability, swellability, pK_a values and ion exchange capacity.     

国内外干法变性淀粉研究进展

综述了国内外干法变性淀粉制备的工艺路线、工艺参数和相关设备的研究,指出了干法生产变性淀粉是一种很有前途的变性淀粉生产方法。     

豌豆抗性淀粉的酶法制备及其性质研究

以豌豆淀粉为原料,经糊化、普鲁兰酶脱支和凝沉处理,使其分子结构发生改变,制备出高含量的抗性淀粉,并研究了其理化性质。结果表明,在加酶量为300 ASPU/g,脱支时间12 h,凝沉时间24 h时,抗性淀粉含量达到最高52.66%;经糊化、脱支和凝沉处理后的样品结晶结构由C型变为B+V型;随着抗性淀粉含量的增加,其溶解度逐渐降低且均高于原淀粉,但膨胀度均低于原淀粉;消化产物随抗性淀粉含量的增加而降低。     

Morphology of Some Legume and Tuber Starches Grafted with Polyacrylonitrile

Morphological aspects of three legumine and three tuber starches and their graft copolymers with polyacrylnitrile (PAN) prepared from granular and gelatinised states have been reported. Scanning electron microscopy revealed that grafting characteristics of legumine and tuber starches are quite different. In potato starch the hydrolysed S-g-PAN product showed that the grafting has occurred in the interior. In case of sweet potato starch a little grafting occurred on the surface of depression while normal grafting might have taken place in the interior through the depression. Little grafting seems to have occurred inside the tapioca starch granules. The grafting on legumine starches has mainly occurred on the surface of granules.     

预糊化变性淀粉在麻糬面包中的应用

本文研究了预糊化木薯变性淀粉、预糊化马铃薯变性淀粉、预糊化玉米变性淀粉和预糊化大米粉对麻糬面包的感官评价、比容、弹性的影响,分析了预糊化变性淀粉的布拉班德粘度曲线,结果表明,预糊化木薯变性淀粉与预糊化马铃薯变性淀粉制作的麻糬面包口感及外观较好,而预糊化玉米变性淀粉与预糊化大米粉制作的产品口感不佳、比容小,预糊化木薯变性淀粉与预糊化马铃薯变性淀粉质量比为1:1时,麻糬面包加工性能好、口感清爽、弹性强、比容较大、保型性佳。     

4种改性淀粉与明胶共混膜的制备与性质比较

该研究对4种改性淀粉（羟丙基二淀粉磷酸酯、羟丙基淀粉、氧化淀粉、氧化羟丙基淀粉）的溶解度、膨胀势、糊化特性、老化值进行了分析和比较。溶解度高、膨胀势小、糊化特性好、老化值低的淀粉,较适宜作为制备共混膜的原料。在此基础上加入甘油或聚乙二醇400（Polyethylene Glycol,PEG400）作为增容剂,并对配方中水和甘油加入量进行了初步摸索,运用紫外、扫描电镜和拉伸试验机测定共混膜的透光性、透水气性、微观形貌和机械性能。结果表明：羟丙基淀粉溶解度最高,为86.42%;膨胀势最低,为0.086%,稳定性更好;黏度较低,老化值较大,流动性高,易于成膜。为4种改性淀粉中最适宜和明胶共混的原料。利用紫外分光光度计进行全波长扫描测量透光率;利用不同时间水保留质量反应透水汽性;用扫描电镜放大500~6 000倍对微观形貌观察,用拉伸材料试验机对机械性能进行测试。通过比较,发现以羟丙基淀粉为原料的共混膜,具有较好的透明度（优于纯明胶样品的透光度）,良好的透水汽性和机械性能。微观形貌也是呈现出相容性较好的形态（SEM显示）,相较于PEG400,甘油作为增容剂时共混膜的微观形貌横截面均匀光滑,内容物相容性好。明胶:甘油:水质量比为1:9:3:13制得共混膜透光性、透水气性、机械性能最佳,具有较好的实际应用价值。     

Graft Copolymers of Starch and Polyacrylonitrile. Effect of Source

Graft copolymers of tuber and legume starches with polyacrylonitrile (PAN) have been prepared. Molecular weight, frequency of grafting, and adsorbencies of saponified products have been investigated. Yield and add-on of granular graft copolymers are dependent on the source of starch. Parameters for gelatinized graft copolymers are almost constant. Yield, add-on, molecular weight and adsorbencies are different for the granular graft copolymer of garden pea starch. On pretreatment up to 70°C, these parameters are comparable with those of other starch graft copolymers.     

Enzymic Digestibility of Modified Starches

Gelatinized unmodified and modified wheat starches were hydrolysed with porcine pancreatic α-amylase. The digestibility was estimated by increase in reducing power and by decrease in blue value. The digestibility of the starch was considerably reduced by substitution with hydroxypropyl and acetate groups, while crosslinking with phosphate had a lower effect on its digestibility. Etherification with hydroxypropyl groups lowers the digestibility of the starch to a larger extent than esterification with acetate. Substitution with hydroxypropyl and acetate groups increases the degree of random attack by porcine pancreatic α-amylase on the wheat starch to a larger extent than cross-linking with phosphate.     

有机改性膨润土的制备及其性能研究

本研究采用十八烷基三甲基溴化铵(OTAB)对膨润土进行有机改性并在造纸法再造烟叶浆料中进行了应用.使用扫描电镜(SEM)、傅立叶红外光谱(FTIR)、热重(TG)、X射线衍射(XRD)对制得的改性膨润土进行了实验分析.结果表明,有机表面活性剂OTAB已经进入膨润土的片层间,晶面间距由1.256nm增大到2.437nm;晶面间距增大的最佳实验条件为:OTAB用量为40％,反应时间为2h,反应温度为75℃.对有机改性膨润土与阳离子瓜尔胶(CGG)协同助留造纸法再造烟叶浆料的研究发现,改性膨润土/CGG的助留效果优于未改性膨润土的助留效果.     

神经酰胺修饰醇质体的制备与表征

为了提高醇质体的稳定性,作者采用神经酰胺Ⅲ（ceramideⅢ,Cer3）修饰醇质体。首先考察了Cer3质量浓度对醇质体稳定性的影响,后将视黄醇棕榈酸酯（retinyl palmitate,RP）作为脂溶性活性物载入Cer3醇质体,研究了RP-Cer3醇质体的稳定性、稳定机制及体外释放性能。结果显示,当Cer3质量浓度为1.0 mg/mL时,Cer3醇质体的稳定性最好。RP-Cer3醇质体的RP质量浓度为2.0 mg/mL时,粒径为（68.4±1.1） nm,室温储存120 d,外观和粒径均无明显变化。X射线衍射和全反射傅里叶红外光谱表明RP被包载于醇质体中,同时,红外光谱图也说明了RP与醇质体存在氢键相互作用。研究表明,Cer3的加入会降低醇质体流动性从而提高其稳定性,且RP-Cer3醇质体具有较好的体外释放性能。     

改性玉米淀粉的物理化学研究

对天然玉米淀粉和五种化学改性玉米淀粉的糖化性质进行了比较。改性玉米淀粉包括下列五种,磷酸淀粉,交联磷酸淀粉,醋酸淀粉A,醋酸淀粉B和羟丙基淀粉。使用差热扫描量热计测定了糊化的热力学参数,同时用显微镜观察了糊化过程。研究表明,五种改性玉米淀粉的糊化热都比天然的玉米淀粉小,测量冷的淀粉糊的流动性质表明只有羟丙基玉米淀粉比天然玉米淀粉的帖度高。     

Characterization of Colombian Maize Starches

Starch from 18 different Colombian maize varieties was extracted and characterized. Microscopic examination showed that most of the granules were larger than those reported for North American maize starches. Iodine binding capacities corresponded to those of normal maize starch. Limiting viscosity numbers demonstrated a significant increase beginning with Series 300 and gelatinization temperatures showed a tendency to decrease with increasing cultivation altitudes. Pasting curves of starches extracted from Opaque-2 maize were considerably different from their respective parent hybrids.     

Reactivity of Modified Starches with Isocyanates

Various substituents were added onto starch by means of esterification or etherification so that their effect on reactivity of starch with isocyanates in a nonpolar solvent could be studied. Maximum reactivity of the modified starches was achieved when the degree of substitution (D.S.) was about 0.7. Cured urethane plastics made from formulations containing 20 % of the starch derivatives demonstrated maximum breaking energy at D.S. 0.7.     

改性红枣多糖的制备和结构表征

以哈密大枣为原料,采用水提醇沉法提取和脱脂脱蛋白透析获得红枣多糖,通过羧甲基化法、硫酸法和硒化法对红枣多糖进行改性,并对其改性后的红枣多糖进行初步结构表征。结果表明：红枣多糖分子量为136 413 Da、多糖含量为49.96%、;羧甲基化红枣多糖的得率最高为91.1%,取代度为0.42、多糖含量为36.51%、分子量为46 637 Da;硫酸化红枣多糖的取代度为1.65、多糖含量为42.73%、分子量为9970Da和6149Da;硒化红枣多糖硒元素含量为（580.15±11.96）μg/g、多糖含量为44.56%、分子量为136 153 Da。单糖组成分析中硒化红枣多糖半乳糖醛酸含量最高,为53.23%,硫酸化红枣多糖、羧甲基化红枣多糖与红枣多糖中半乳糖醛酸含量（48.17%）相比均有所降低,分别为30.51%和39.60%。红外光谱分析的表征结果可知改性后多糖仍具有多糖的官能团,其他红外指标的变化说明改性成功。     

聚乙烯亚胺改性硅藻土的制备与表征

采用聚乙烯亚胺(PEI)和十二烷基磺酸钠(SDS),通过浸渍法对硅藻土进行表面改性,研究了硅藻土对PEI的吸附,硅藻土改性后Zeta电位、粒径和形貌特征的变化,以及纸浆中添加改性硅藻土对浆料Zeta电位和滤水性的影响。研究结果表明,PEI能够对硅藻土进行有效改性,与硅藻土相比,PEI改性硅藻土颗粒表面Zeta电位由负电性转变为正电性,粒径增加,当PEI平衡吸附浓度为0.24 mg/m L时,硅藻土颗粒Zeta电位和粒径分别为25.03 m V和14.05μm。PEI改性硅藻土作为造纸填料,可有效提高浆料Zeta电位,并改善浆料滤水性能。