淀粉接枝共聚物制备的影响因素的研究进展

综述了制备淀粉接枝共聚物过程中,淀粉种类、其是否糊化,引发剂及单体的选择及其用量,以及反应温度和反应时间等因素对制备淀粉接枝共聚物的影响,指出应根据所需产物性能要求,综合考虑各方面因素的影响.并提出开发新的廉价而高效的引发剂成为市场所需,淀粉制备工艺的简约处理以及性能优良的淀粉衍生物产品的开发值得人们进一步的深入探讨.     

Biomimetic Robust Starch Composite Films with Super-Hydrophobicity and Vivid Structural Colors

The starch composite films (SCFs) will be one of the best alternative packaging materials to petroleum based plastic films, which mitigates white pollution and energy consumption. However, weak mechanical stability, water resistance, and dyeability has hindered the application of SCFs. Herein, a bioinspired robust SCFs with super-hydrophobicity and excellent structural colors were prepared by fiber-reinforcement and assembling SiO₂/Polydimethylsiloxane (PDMS) amorphous arrays on the surface of SCFs. The properties of the designed SCFs were investigated by various methods including scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), a tensile test, contact angle (CA) test, and an optical test. The results showed that the obtained SCFs possessed a higher tensile strength (55.17 MPa) attributed to the formed abundant hydrogen bonds between the molecular chains of the starch, cellulose fiber, and polyvinyl alcohol. Benefiting from the nanostructure with rough surface which were modified by materials with low surface free energy, the contact angle and sliding angle of the film reached up to 154° and 2°, respectively. The colors which were produced by the constructive interference of the coherent scattered light could cover all of the visible regions by tuning the diameters of the SiO₂ nanoparticles. The strategy in the present study not only reinforces the mechanical strength and water resistance of SCFs but also provides an environmentally friendly way to color the them, which shows unprecedented application potential in packaging materials of the starch composite films.     

木薯发酵制备酒精后剩余残渣的综合利用

木薯发酵制备乙醇会产生大量以淀粉和纤维素为主要成分的残渣。经实验证明,在浓硫酸(60%)、浓硝酸和催化剂共同作用下,经水解-氧化-水解可成功地将木薯渣制备成草酸。实验确定了用木薯渣制备草酸的较优条件,测定了产品的熔点,分析了剩余残渣、废水,结果表明剩余残渣和废水不会对环境造成污染,既为草酸的生产提供了新思路,又为农产品的残渣综合利用找到途径,发展前景广阔。     

The Potential Application of Starch and Walnut Shells as Biofillers for Natural Rubber (NR) Composites

The goal of this study was application of corn starch and ground walnut shells in various amounts by weight as biofillers of natural rubber (NR) biocomposites. Additionally, ionic liquid 1-butyl-3-methylimidazolium chloride (BmiCl) and (3-aminopropyl)-triethoxysilane (APTES) were used to increase the activity of biofillers and to improve the curing characteristics of NR composites. The effect of biofillers used and their modification with aminosilane or ionic liquid on the curing characteristics of NR composites and their functional properties, including crosslink density, mechanical properties in static and dynamic conditions, hardness, thermal stability and resistance to thermo-oxidative aging were investigated. Starch and ground walnut shells were classified as inactive fillers, which can be used alternatively to commercial inactive fillers, e.g., chalk. BmiCl and APTES were successfully used to support the vulcanization and to improve the dispersion of biofillers in NR elastomer matrix. Vulcanizates with starch, especially those containing APTES and BmiCl, exhibited improved tensile properties due to the higher crosslink density and homogenous dispersion of starch, which resulted from BmiCl addition. NR filled with ground walnut shells demonstrated improved resistance to thermo-oxidative aging. It resulted from lignin present in walnut shells, the components of which belong to polyphenols, that have an antioxidant activity.     

氧化芋头淀粉理化性质研究

以芋头淀粉为原料、过氧化氢为氧化剂,在碱性介质中制备了低氧化度芋头淀粉。经扫描电镜分析,氧化芋头淀粉颗粒呈多角状,平均颗粒直径18.09μm。X-射线衍射确定其晶体形貌为A型结构。流变学分析其糊化温度为79.5℃、特性粘度为2.505 Pa.s,粘弹性曲线显示其粘性大于弹性。其塑性测定结果符合Croass模型,稠度指数为85.56 s。     

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。     

Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril

Cellulose nanofibril (CNF) was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin (PAE) or cationic starch (CS) was used as the cationic component. Their strengthening effects were investigated for low-basis-weight (30 g/m²) paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio. Using the PAE/CNF or CS/CNF dual system, it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system. For example, the paper using the PAE (0.4%)/CNF (0.3%) dual system exhibited 89% higher wet tensile strength than the paper using the single PAE (0.4%) system, and the paper using CS (1.3%)/CNF (0.3%) dual treatment showed 21% higher dry strength than that using the single CS (1.3%) system. However, the PAE/CNF system only showed small improvement in the dry strength of paper (11% higher than that of paper using the single PAE system), so did the CS/NFC system on wet strength improvement (only 17% higher than that of paper using the single CS system).     

阳离子淀粉的合成

本文阐述了CS—3淀粉的反应机理,并结合工业生产指出阳离子淀粉的合成中重要的技术问题;另外还利用重复取样的方差分析方法确定了CS—3淀粉的工艺操作条件及主要影响因素。