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61.
以高直链淀粉(HS)为原料,通过“还原胺化-点击化学法”在其还原性端的潜在醛基上进行磁化分子修饰,得到具有磁性的变性淀粉(MMS),并在外磁场作用下制备再生淀粉膜。具体包括在HS分子唯一的潜在醛基上引入炔基,对四氧化三铁粒子(MNP)进行硅烷包覆得到叠氮化磁体粒子(azide-MNPs),两者经点击化学反应得到分子链末端带磁的变性淀粉。借助XRD、FTIR、NMR和MALDI-TOF MS对产物进行结构表征,结果表明,磁体粒子精准接枝到高直链淀粉分子还原末端,得到目标产物MMS。再生淀粉膜性能测试结果表明,在外磁场诱导条件下MMS逐渐趋于分子有序排列,制得的再生淀粉膜较纯CMS淀粉膜断裂伸长提升49.5%,断裂强度提升88.3%,短程有序程度提高。该文为基于外加磁场下的淀粉再生膜结构设计和力学性能调控提供了新思路。 相似文献
62.
马铃薯淀粉渣的羧甲基化研究 总被引:5,自引:0,他引:5
研究了马铃薯淀粉渣与氯乙酸进行羧甲基化反应的一般规律,考察了反应温度、反应时间、原料配比等因素对产物取代度的影响,通过正交试验,找到了最佳反应条件,并对产物性能进行了测试。 相似文献
63.
干法合成阳离子淀粉絮凝剂的初步研究 总被引:3,自引:0,他引:3
研究了干法合成阳离子淀粉絮凝剂的方法。结果表明,制备阳离子淀粉絮凝剂的最佳工艺条件为:在反应体系中水的质量分数为35%、阳离子醚化剂与NaOH混合温度低于110℃的条件下,阳离子醚化剂与淀粉物质的量比为0.35,NaOH与阳离子醚化剂物质的量比为1.4,反应温度90℃,反应时间4h。在此条件下合成的阳离子淀粉相对黏度为2.0。 相似文献
64.
Thermoplastic extrusion—the mechanism of the formation of extrudate structure and properties 总被引:6,自引:0,他引:6
Vladimir B. Tolstoguzov 《Journal of the American Oil Chemists' Society》1993,70(4):417-424
Systems processed by thermoplastic extrusion can be regarded as heterophase polymer melts of incompatible water-plasticized
biopolymers. In the process of thermoplastic extrusion, proteins and polysaccharides are melted at high pressure and temperature
below the temperature region of their thermal decomposition. Dispersed particles of these systems can be deformed in flow.
The mixed-melt anisotropic structure, formed in flow, is fixed by rapid conversion of the melt jet that lets the extruder
die from a viscous state to a rubber-like state and then to a glassy state caused by cooling and drying. Incompatibility of
proteins and polysaccharides in their water-plasticized melt mixtures impacts on structure formation and texturization during
thermoplastic extrusion.
Presented at the 20th ISF World Congress and 83rd AOCS Annual Meeting and Expo, May 10–14, 1992, Toronto, Ontario, Canada. 相似文献
65.
Poly(lactic acid) (PLA) and wheat starch are biodegradable polymers derived from renewable sources. A previous study showed that thermally blending starch and PLA in the presence of methylenediphenyl diisocyanate (MDI) enhanced the mechanical properties of the blends. In this work, blends of PLA with various levels of wheat starch and MDI were hot mixed at 180°C then hot‐pressure molded at 175°C to form test specimens. The blends were characterized for mechanical properties, fracture microstructure, and water absorption. Pure PLA had a tensile strength of 62.7 MPa and elongation of 6.5%. The blend with 45% wheat starch and 0.5 wt % MDI gave the highest tensile strength of about 68 MPa with about 5.1% elongation. The blend with 20% starch and 0.5 wt % MDI had the lowest tensile strength of about 58 MPa with about 5.6% elongation. Dynamic mechanical analysis showed that storage modulus increased and tan δ decreased as starch level increased, but almost leveled off when starch level reached 45% or higher. Water absorption of the blends increased significantly with starch content. Yet the blend, if water proofed on its surface, has potential for short‐term disposable applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1257–1262, 2002; DOI 10.1002/app.10457 相似文献
66.
沙枣淀粉烷基多糖苷的制备与性能 总被引:8,自引:2,他引:8
以植酸和对甲苯磺酸二元体系为催化剂,以沙枣和脂肪醇作原料,采用转糖苷法合成了烷基多糖苷表面活性剂。确定较佳工艺条件为:m(乙二醇)∶m(十二醇)∶m(沙枣粉)=12∶1∶1;常压反应,温度90~100℃;沙枣糖转化率接近100%。测定其表面张力为25 9~28 9mN·m-1,25℃时临界胶束浓度为2×10-5mol/L,HLB值为18,并对其结构进行了红外测定。合成的烷基糖苷(APG)产品可应用于农药乳化,餐具洗涤剂等。 相似文献
67.
Polycaprolactone (PCL)/starch and PCL/starch/pine‐leaf composites, which can be possibly applied as biodegradable food packaging materials with natural pine flavor, were prepared and characterized in this study. The effect of incorporating a silane coupling agent at different content levels on the physical properties and morphology of the composites was studied. To investigate the melting behavior of the composites, a differential scanning calorimetry was employed. A universal testing machine was used to investigate the tensile properties of the composites and the water absorption properties of the composites were also investigated. Scanning electron microscope was used to investigate the morphology of the composites. The physical properties and morphology of the PCL/starch and PCL/starch/pine‐leaf composites were largely affected by the composition, especially the content of the silane coupling agent. The silane coupling agent led to a much better interfacial compatibility between the PCL matrix and the fillers and resulted in better physical properties of the composites. The PCL/starch/pine‐leaf composite with the silane coupling agent showed a morphology, indicating a good interfacial adhesion between the PCL matrix and the fillers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 928–934, 2007 相似文献
68.
Graft copolymers were synthesized by graft copolymerization of butyl acrylate (BA) onto sodium salt of partially carboxymethylated starch (Na‐PCMS). Ceric ammonium nitrate (CAN), a redox initiator, was used for initiation of graft copolymerization reaction. All the experiments were run with Na‐PCMS having degree of substitution, DS = 0.35. The grafting reaction was characterized by parameters such as % total conversion (%Ct), % grafting (%G), % grafting efficiency (%GE), and % add‐on. Graft copolymers were characterized by infrared spectral analysis and scanning electron microscopy. Variables affecting graft copolymerization reaction such as nitric acid concentration, reaction time, reaction temperature, and ceric ion concentration were investigated. The results revealed that 0.3M CAN as initiator, 0.3M HNO3, with reaction time 4–4.5 h at 25–30°C were found as suitable parameters for maximum yield of graft copolymerization reaction. © 2006 Wiley Periodicals, Inc. JAppl Polym Sci 102: 3334–3340, 2006 相似文献
69.
面粉中的淀粉组分对面条蒸煮品质的影响 总被引:6,自引:0,他引:6
从面粉中提取淀粉、直链淀粉和支链淀粉,按不同的梯度添加到原面粉中制作面条.然后测定面条的蒸煮特性,寻找出淀粉、直链淀粉和支链淀粉对面条蒸煮品质影响的规律.实验表明:随着淀粉添加量的增加,面条的干物质吸水率、干物质损失率、蛋白质损失率都出现了上升的趋势;随着直链淀粉添加量的增加,面条的干物质吸水率出现了下降的趋势,而干物质损失率、蛋白质损失率都出现了上升的趋势;随着支链淀粉添加量的增加,面条的干物质吸水率出现了上升的趋势,而干物质损失率、蛋白质损失率都出现了下降的趋势. 相似文献
70.
通过可生化量即生化需氧量(BOD)与化学需氧量(COD)的比值对一种已在市场中得到应用的接枝淀粉(ST-T)进行生物降解性评价。测定结果表明ST-T的可生化量的平均值是0.340,是PVA的27-85倍,也比酸解淀粉的可生化量值略高,具有十分优异的生物降解性。 相似文献