辐照淀粉与PAM共煮浆的特征分析

淀粉经-γ射线辐照与聚丙烯酰胺混合共煮糊化时,在糊化液中可实际检测出与共煮的聚丙烯酰胺发生的接枝反应。同时,辐照淀粉与聚丙烯酰胺混合煮浆时,高压煮浆具有更高的黏度,这种黏度增高的现象可能与交联有关。正是由于这种化学特性,使辐照淀粉在实际调浆中有十分稳定的黏度。     

木素的接枝改性

以特性粘度为表征量,用四因素三水平正交实验和单因素实验研究了K2S2O8引发木素磺酸钙接枝丙烯酰胺过程中多种因素对接枝产物特性粘度的影响,这些因素包括引发剂的用量、丙烯酰胺用量、反应温度、反应时间等,得出了最佳的反应条件为:K2S2O8用量0.5×10-2mol/L,丙烯酰胺用量1.4mol/L,反应温度50℃,反应时间2.5h;将接枝共聚物用于碱性品红染料的脱色处理,可获得较好的脱色效果,脱色率可达85.6%,脱色量180mg/g.     

淀粉与丙烯酰胺接枝共聚物性质的研究

研究了小麦淀粉与丙烯酰胺的接枝共聚物的物理特性和结构特征,实验结果表明:该接枝共聚物在热性质上与原淀粉有明显的区别,其糊化温度比原淀粉略低,粘度热稳定性及溶解度较原淀粉均有提高。接枝共聚反应不仅发生在淀粉颗粒的表面上,而且也发生在颗粒结构的内部,但反应仅发生在淀粉的无定型区。     

颗粒淀粉与丙烯酰胺的接枝共聚

本文以小麦淀粉为骨架，丙烯酰胺为单体，溴酸钠为引发剂，使原淀粉与丙烯酰胺接枝共聚。对接枝过程中引发剂浓度、单体浓度、反应温度、反应时间、ｐＨ值，原料配比诸因素对产物的影响进行了讨论，并探讨了产物可以保持颗粒状态的条件。     

尿素与淀粉混合浆液的性能研究

研究了尿素与淀粉的物理混合物在煮浆过程中的反应性能及尿素对淀粉浆液粘度和粘度稳定性的影响,分析了尿素用量对淀粉浆液浆膜性能的影响,指出：尿素具有良好的提高淀粉浆液粘度热稳定性的作用;尿素与淀粉的物理混俣物在煮浆过程中不会生成真正的尿素淀粉。     

引发剂对淀粉接枝聚丙烯酰胺影响的研究进展

淀粉-丙烯酰胺接枝共聚物具有价廉、无毒、易生物降解等优点,受到研究者的广泛重视.我国在淀粉接枝聚丙烯酰胺的研究方面比较深入,对引发剂影响如硝酸铈铵、过硫酸盐、锰盐、辐射法等进行对比研究,选用不同的接枝共聚工艺方式,优化反应工艺条件,制备了具有不同特性的淀粉接枝聚丙烯酰胺,并把接枝的淀粉应用在废水处理、造纸湿部、吸水剂等多方面.就我国目前几大类引发体系对淀粉接枝聚丙烯酰胺的制备与应用方面进行综述.     

毛精纺经纱上浆用浆料的制备及其性能

针对采用明胶对羊毛纱上浆时存在浆膜脆硬、低温凝沉的问题,通过明胶与丙烯酰胺接枝共聚的方法,制备明胶-丙烯酰胺接枝共聚浆料(Gel-M),采用红外光谱、DSC、X射线衍射对制备的Gel-M浆料结构进行分析表征,对比测试明胶、明胶/聚丙烯酰胺混合浆料、Gel-M共聚浆料的浆液及浆膜性能。结果表明:Gel-M浆料在室温条件下不凝沉,浆液流动性好,Gel-M共聚浆膜柔韧性明显好于明胶及明胶/聚丙烯酰胺混合浆料。采用制备的Gel-M浆料对羊毛纱上浆,测得浆纱断裂强力、耐磨次数增加,毛羽减少,满足了经纱织造的要求。     

羧甲基淀粉与聚丙烯酰胺接枝共聚反应研究

该文简述羧甲基淀粉与聚丙烯酰胺接枝共聚反应机理、聚合方法及反应中引发剂选择问题,并对羧甲基淀粉与聚丙烯酰胺接枝共聚物应用前景进行展望。     

干法变性温度对淀粉糊化及混合浆相分离的影响

通过比较不同温度处理过的淀粉试与原淀粉的Brabender粘度曲线,探讨了变性淀粉浆料干法生产过程中反应温度与淀粉糊化特性之间的联系,然后以初显分离时间和沉降率为量化指标,定量评估了该温度对淀粉与PVA－1799及VPA－1788混合浆液相分离的影响,实验结果表明,提高变性淀粉浆料干法生产过程中的反应温度,有助于降低淀粉的糊化温度和浆液粘度,并能减小淀粉与PVA混合浆液的初始相分离速度。     

机械活化预处理对木薯淀粉与丙烯酰胺接枝共聚反应的影响

采用搅拌球磨机对木薯淀粉进行机械活化,以不同活化时间的木薯淀粉为原料、过硫酸铵-亚硫酸氢钠为引发剂、丙烯酰胺为单体制备淀粉接枝共聚物,分别考察机械活化时间、反应时间、引发剂浓度、单体浓度及反应温度等因素对木薯淀粉与丙烯酰胺接枝共聚反应的影响。结果表明,机械活化30 min的木薯淀粉与丙烯酰胺接枝共聚反应的适宜工艺条件为反应时间60 min,淀粉浓度0.37 mol/L,单体浓度1.52 mol/L,过硫酸铵浓度3.0mmol/L,亚硫酸氢钠浓度6.0 mmol/L,反应温度60℃时,接枝率和接枝效率分别为145.1%、85.0%,而原淀粉（预糊化）在相同条件下,接枝率和接枝效率分别为100.3%、60.2%。表明了机械活化预处理对木著淀粉的接枝共聚反应有显著的强化作用。     

Characterization of gelatinized corn starch suspensions and resulting drop size distributions after effervescent atomization

Effervescent atomization is a promising method for economical atomization of high viscous liquids like gelatinized corn starch suspensions. The gelatinization of starch has strong influence on the viscosity of starch suspensions. It was characterized adapting a method for determination of the gelatinization degree. Rheological properties of gelatinized corn starch suspensions with concentrations ranging from 5 to 7 wt.-% were investigated. Effervescent atomization proved to be largely invariant to variations of liquid viscosity in this range. Relative gas injection pressure proved to be of highest influence on the resulting drop size distribution when varying only atomizer geometry. Applying Abel inversion to drop size measurement results depicted the opposite trend of drop sizes depending on radial position in the spray than observed by other researchers working with aqueous glass bead suspensions. Compared to conventional external mixing pneumatic atomization a reduction of atomization gas quantity of up to four times could be achieved.     

醋酸酯支链淀粉的制备及其性能

摘要： 研究醋酸酯支链淀粉的制备与性能。以玉米淀粉为原料,以醋酸酐为酯化剂,采用干法制备醋酸酯支链淀粉。以透光率、糊化温度和取代度为指标,采用正交实验确定了制备醋酸酯化支链淀粉的最佳条件。测定并分析了醋酸酯支链淀粉的取代度、IR图谱和X-衍射光谱。测定并比较了醋酸酯支链淀粉与玉米淀粉、支链淀粉、醋酸酯淀粉的浆纱强伸性、透光率、糊化温度、黏度、黏度热稳定性。实验结果表明：醋酸酯支链淀粉与支链淀粉的X-衍射光谱基本相同,为无定型晶体结构;与玉米淀粉、支链淀粉和醋酸酯淀粉比较,醋酸酯支链淀粉具有黏度低、糊化温度低、取代度高、透明度高、黏度热稳定性高等特点,是一种比醋酸酯淀粉更好的纺织浆料。     

半糊化浆纱技术的上浆机制

半糊化浆纱技术是基于使用淀粉为主浆料、浆纱工艺采用中温调浆、浆槽不加热的一种新型浆纱技术。本文通过采用扫描电镜系统对半糊化浆纱表面淀粉浆料糊化状况、浆纱横截面浆液浸透状况的观察,提出了半糊化上浆技术的机理。研究结果表明,半糊化浆液中含有一定量糊化了的浆液和大量未糊化的淀粉颗粒,完全糊化了的淀粉浆液由于黏度小而容易浸透到纱线内部,大量吸水而未糊化的淀粉颗粒粘附在纤维和纱线表面,浆纱烘燥时,黏附在纤维和纱线表面未糊化的淀粉颗粒破裂被覆到纤维和纱线表面,并与浸透到纤维之间的浆液发生粘结,浸透到纤维之间的糊化浆液成为表面颗粒淀粉糊化后粘附的“根”,使得浆膜对纱线形成了包覆。     

超高压处理对玉米淀粉结构及糊化特性的影响

利用光学显微、X-射线衍射、差示扫描量热、快速黏度分析技术研究了超高压处理对玉米淀粉结构及糊化性质的影响。结果显示,超高压处理能使玉米淀粉糊化,处理压力为500 MPa及600 MPa时完全糊化所需保压时间分别为15 min和5 min,但400 MPa超高压处理30 min也不会使淀粉糊化。超高压糊化过程中,淀粉颗粒结构逐渐破坏膨胀,结晶结构由A型向V型转化,RVA黏度曲线峰值黏度逐渐消失。适宜条件的超高压处理对淀粉颗粒同时具有韧化和晶体破坏作用。其中,400 MPa超高压处理5~10 min时,淀粉颗粒内部韧化作用占优,因而表现为相对结晶度、糊化温度(T_o,T_p)及糊化焓增加,而RVA曲线峰值黏度降低。     

Change in the Rheology of Starch Adhesive During Gelatinization

In this paper the viscosity increase of the starch paste during gelatinization is examined. Upon heating, raw starch granules gelatinize and the paste viscosity of the starch adhesive increases dramatically. Bonding develops further through the dehydration of the gelatinized starch by the board. Bond setting of carrier-type (mixture of dissolved and raw) starch on paperboard in the corrugated board operation is thought to result from a combination of thermal gelatinization and dehydration by the board.     

BACK EXTRUSION and SIMULATION of VISCOSITY DEVELOPMENT DURING STARCH GELATINIZATION

A generalized apriori theoretical model relating apparent viscosity of protein dough to several independent variables was used to model gelatinized starch dispersions. Independent variables in the original model were shear rate, temperature, moisture content, temperature-time history and strain history. the model is applied here to corn starch dispersions gelatinized using various temperature-time treatments. Apparent viscosity of a 13.7% gelatinized cornstarch solution at constant shear rate and strain history was measured at 20 C using a back extrusion technique. Activation energy of gelatinization was estimated as 210 kJ/mol (50 kcal/mol) over the range 81–95 C. the activation energy decreased in the range 95–105 C.     

Gelatinization of Thermally Treated Starch Mixed with Sodium Hydroxide in the Solid State

The effect of thermal treatment on maize starch mixed with different amounts of sodium hydroxide, in the solid state, on its gelatinization was thoroughly investigated. Besides, the rheological properties of the products which undergo gelatinization by addition of water at room temperature after treatment were also investigated. It was found that gelatinization of thermally treated starch with sodium hydroxide in the solid state starts only at a ratio of alkali: starch of 1:10 or more regardless of the temperature of treatment. The rheological properties as well as the apparent viscosity at various rates of shear were found to be dependent on both the temperature of treatment an the sodium hydroxide: starch ratio. Storing of the thermally treated gelatinized starch pastes for 7 days is accompanied by a remarkable increase in their apparent viscosity at any specific rate of shear which may be due to the effect of sodium hydroxide on starch during storing.     

Effect of honey types and concentration on starch gelatinization

The complex and variable composition of honey, depending on source, season and processing, means different honey samples could cause variation in the characteristics of the finished product. The objective of this study was to determine how the minor components present in honey affect starch gelatinization. A Rapid Visco Analyser was used to measure changes in viscosity when unmodified maize starch was gelatinized in a honey or model sugar solution. When honey was compared to equivalent blends of sugars, there was an increase in starch viscosity with increasing levels of addition. However, at the same level, honey gave a lower viscosity than the blends of sugars. Honeys from different sources (differing in pH and amylase activity) show a varied effect on starch gelatinization, with starch viscosity increasing with addition level for six of the honeys, but decreasing with increasing addition level for two honey samples. Varying the pH also produced variation in starch gelatinization patterns between honey types. Between pH 3.0 and 4.0, starch viscosity was similar for all four honey types studied, while above this pH there were differences between all honey types. As expected, starch viscosity decreased as the solution pH neared the optimum for honey amylase activity (pH 5.3-5.6), though it did not increase as the pH moved away from the honey amylase activity optimum. Differences between honey samples, and between honey and a model sugar mixture, in their effect on starch gelatinization was attributed to honey amylase activity and the composition and concentration of minor organic compounds present.     

超高压辅助制备醋酸酯淀粉结构性质研究

以玉米淀粉为原料,乙酸酐为反应试剂,NaCl为反应介质,采用超高压辅助制备醋酸酯淀粉,利用光学显微、X-射线衍射、快速黏度分析技术对醋酸酯淀粉结构性质进行分析。研究表明,颗粒态醋酸酯淀粉结晶类型与原淀粉相同,当处理压力为600 MPa时淀粉糊化,颗粒结构被破坏,A型结晶向V型结晶转换,但糊化并不利于醋酸酯淀粉取代度的增加。适量NaCl的添加有利于超高压处理时淀粉颗粒态的维持,因而有效提高了醋酸酯淀粉的取代度。当NaCl溶液浓度为1.0%、乙酸酐添加量为2.0%、压力为400MPa时,所制备的醋酸酯淀粉取代度达到最大值(0.090),且表现出较高的峰值黏度(400.00cP)。     

辣根过氧化物酶催化淀粉接枝丙烯酸甲酯浆料制备及其上浆性能

为改善淀粉浆液对涤棉混纺纱的黏附性和浆膜的力学性能,采用辣根过氧化物酶(HRP)/乙酰丙酮(ACAC)/过氧化氢(H2O2)引发体系,催化酸解淀粉接枝丙烯酸甲酯。通过傅里叶红外光谱、扫描电子显微镜和X射线衍射对接枝淀粉进行表征,并分析其流变特性。结果表明,在HRP酶催化作用下丙烯酸甲酯与未糊化酸解淀粉发生接枝共聚反应,且对酸解淀粉结晶度影响不大;淀粉接枝改性后浆液黏度增大,黏弹性增加,呈现更具弹性的流体特征;相比于酸解淀粉,含有柔性接枝支链的淀粉浆液对涤/棉黏附性有明显提高,浆膜断裂伸长率和断裂强度均有增加,力学性能得到改善。