疏水淀粉衍生物的制备

淀粉酯化;长链烯基琥珀酸酐;疏水淀粉衍生物的制备     

Morphology and mechanical properties of poly(vinyl alcohol) and starch blends prepared by gelation/crystallization from solutions

 In an attempt to produce biodegradation materials, poly(vinyl alcohol) (PVA)–starch (ST) blends were prepared by gelation/crystallization from semidilute solutions in dimethyl sulfoxide (Me₂SO) and water mixtures and elongated up to 8 times. The content of mixed solvent represented as Me₂SO/H₂O (volume percent) was set to be 60/40 assuring the greatest drawability of PVA homopolymer films. The PVA/ST compositions chosen were 1/1, 1/3, and 1/5. The elongation up to 8 times could be done for the 1/1 blend but any elongation was impossible for blends whose ST content was beyond 50%. When the blends were immersed in water at 20 or 83 °C, the solubility became considerable for an undrawn blend with 1/5 composition and a drawn 1/1 blend with λ=8. To avoid this phenomenon, cross-linking of PVA chains was carried out by formalization under formaldehyde vapor. Significant improvement could be established by the cross-linking of PVA chains. For the 1/1 blend, the amount of ST dissolved in water at 23 °C was less than 3% for the undrawn state and 25% for the drawn film. The decrease in the ST content was enough for use as biodegradation materials. Namely, the water content relating to the biodegradation in soil is obviously different from such a serious experimental condition that a piece of blend film was immersed in a water bath. At temperatures above 0 °C, the storage modulus of the formalization blends became slightly higher than those of the nonformalization blends. The Young's modulus of the drawn films with a draw ratio of 8 times was 2 GPa at 20 °C. Received: 23 June 2000 Accepted: 30 October 2000     

新疆小麦粉的特性及面条专用粉的应用研究

通过对美国硬红冬麦粉与新疆小麦粉的比较研究,找到了新疆小麦粉的主要特征及弱点,并针对性地制订了改良方案,为研制新疆的面条专用粉提供了新方法。     

Study of biocatalyst to produce ethanol from starch

This article presents a detailed study on the conditions for achieving a stable biocatalyst to be used in the production of ethanol from starch. Different pellets were used depending on which characteristic of the biocatalyst was being studied: (a) Saccharomyces cerevisiae entrapped in pectin or calcium alginate gel particles; (b) silica containing immobilized glucoamylase entrapped in pectin gel particles; or (c) pectin gel particles, with the silicaenzyme derivative and yeast coimmobilized. The influence of several variables on the mechanical resistance of the particle, on the viability of the microorganism, and on the rate of substrate hydrolysis was studied with biocatalyst. The best conditions found were 6% pectin gel, 2-mm particle diameter, and curein 0.2 M CaCl₂·2H₂O/60 mM acetate buffer, pH 4.2, for gel preparation; and 6.0 g/L of CaCl₂·2H₂O in the fermentation medium. Biocatalyst (c) was successfully tested for the production of ethanol from liquefield manioc flour syrup.     

交联-羧甲基复合变性淀粉的流变与降失水性能

以马铃薯淀粉和氯乙酸为主要原料,通过交联-醚化制备了交联-羧甲基复合变性淀粉(CCMS),考察了所得CCMS糊液的流变性能和在钻井泥浆中的降滤失水性能,并对其降失水原理进行了探讨。结果表明,在质量分数为0.5%~4.0%、温度为20~60℃的实验条件下,CCMS糊液表现为假塑性流体特征,符合Ostwald-Dewaele的经验公式ηa=Kγn-1;将CCMS与中粘羧甲基纤维素(MV-CMC)进行对比实验,结果发现,在饱和盐水泥浆和4%盐水泥浆中,当其用量分别为MV-CMC质量分数的57%和75%时,就可达到钻井液用MV-CMC的增粘、降滤失水性能指标。     

Synthesis,Characterization, and Optimization Studies of Starch/Chicken Gelatin Composites for Food-Packaging Applications

The indiscriminate use of plastic in food packaging contributes significantly to environmental pollution, promoting the search for more eco-friendly alternatives for the food industry. This work studied five formulations (T1–T5) of biodegradable cassava starch/gelatin films. The results showed the presence of the starch/gelatin functional groups by FT-IR spectroscopy. Differential scanning calorimetry (DSC) showed a thermal reinforcement after increasing the amount of gelatin in the formulations, which increased the crystallization temperature (Tc) from 190 °C for the starch-only film (T1) to 206 °C for the film with 50/50 starch/gelatin (T3). It also exhibited a homogeneous surface morphology, as evidenced by scanning electron microscopy (SEM). However, an excess of gelatin showed low compatibility with starch in the 25/75 starch/gelatin film (T4), evidenced by the low Tc definition and very rough and fractured surface morphology. Increasing gelatin ratio also significantly increased the strain (from 2.9 ± 0.5% for T1 to 285.1 ± 10.0% for T5) while decreasing the tensile strength (from 14.6 ± 0.5 MPa for T1 to 1.5 ± 0.3 MPa for T5). Water vapor permeability (WVP) increased, and water solubility (WS) also decreased with gelatin mass rising in the composites. On the other hand, opacity did not vary significantly due to the films’ cassava starch and gelatin ratio. Finally, optimizing the mechanical and water barrier properties resulted in a mass ratio of 53/47 cassava starch/gelatin as the most appropriate for their application in food packaging, indicating their usefulness in the food-packaging industry.     

磷化淀粉的合成及其与聚磷酸铵协效阻燃聚乳酸的性能研究

利用9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)和马来酸酐(MA)对淀粉进行改性得到磷化淀粉(DOPOMASt),通过红外光谱(FTIR)、核磁共振谱(1H-NMR)和X射线光电子能谱(XPS)确定其结构.利用DOPOMASt作为碳源,与聚磷酸铵(APP)复配后通过熔融共混制备了阻燃聚乳酸(PLA)...     

Structure–property relationship in PCL/starch blend compatibilized with starch‐g‐PCL copolymer

The polycaprolactone (PCL)/starch blends were prepared by using the starch‐g‐PCL (SGCL) graft copolymers as compatibilizers, and their mechanical properties were correlated with the compatibilizing effect of the SGCL copolymers having various molecular structures. The modulus and strength of the PCL/starch blend were decreased, whereas the percent elongation and the toughness were increased remarkably with the addition of SGCL having appropriate graft structure. These property changes were analyzed in terms of the PCL crystallinity and the interfacial adhesion between the PCL matrix and starch dispersion phases, which were dominated by the compatibilizing effects of the SGCL copolymers. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2430–2438, 1999     

阳离子淀粉-壳聚糖-丙烯酰胺的接枝共聚研究

以硝酸铈铵为引发剂,合成阳离子淀粉(CS)-壳聚糖(CTS)-丙烯酰胺(AM)接枝共聚物,讨论了反应温度、引发剂浓度、单体用量、反应时间以及壳聚糖用量对接枝共聚反应的影响。结果表明:淀粉中葡萄糖环浓度(cAGU)为0.20 mol/L,mCTS/mCS=1/6,cAM=1.0mol/L,cCe4 =5 mmol/L,反应温度60℃,反应时间3 h时,转化率和接枝效率可分别达到88%和92%以上;转化率随mCTS/mCS增大而增大,接枝效率则随着CTS用量增大降低,CTS的存在使AM均聚的几率增大。     

PREPARATION AND SWELLING PROPERTIES OF SUPER-ABSORBENT POLYMER

A super-absorbent polymer is prepared by graft polymerizing acrylamide (AM) ontopotato starch using ceric ammonium nitrate (CAN) and N, N′-methylene-bis-acrylamide(bisAM) as an initiator and cross-linking agent respectively, and then subjecting the potatostarch-poly(acrylamide) (PAM) graft copolymer (SPAM ) to alkaline saponification. Thewater absorbency (WA) of the sample is nearly 5000 g H_2O/g for dry sample in 24 hat room temperature and is far larger than that of reported in the literature. Thevariables affecting the WA were investigated and optimized, they were: concentrations ofpotato starch, AM, CAN and bisAM were 26.3 g/L, 1.14 mol/L, 10.3 mmol/L and 0.53mmol/L, respectively. The amount of sodium hydroxide was 15 g and the temperatures ofgraft copolymerization and saponification reactions were 60℃ and 95℃. The time of graftcopolymerization and saponification reactions was 2 h, respectively.