可生物降解的钻井液降滤失剂SPS的合成与性能研究

以淀粉为主要原料合成了一种可生物降解的钻井液滤失剂ＳＰＳ，考察了ＳＰＳ的生物降解性及其在淡水泥浆，盐水泥浆和海水泥浆中的性能。结果表明，ＳＰＳ具有良好的降滤失与抗温、抗污染性能，在海水中可被生物降解。     

An improved enzymic method for the determination of native and modified starch

An improved method for the determination of starch by sequential hydrolysis with thermostable bacterial α-amylase and fungal amyloglucosidase is described. Glucose was determined colorimetrically by a glucose oxidase-peroxidase-chromogen system at pH 7. Native normal and waxy starches, and distarch phosphate, gave quantitative yields of glucose with a high degree of precision (coefficient of variation less than 1%). Acetylated distarch phosphate, high-amylose starch and retrograded amylose were initially treated with 1M NaOH for 30 min, then neutralised and analysed successfully as normal starch. Oxidised starch did not give a quantitative yield of glucose because of the presence of dicarboxylic groups in the polymer. For samples containing normal and waxy starch the analysis was carried out in about 4 h. The method was applied to a range of starch-containing foodstuffs and the results are reported.     

瓦楞纸板用抗水淀粉胶配方及性能研究

简要分析了玉米淀粉胶的组成及对其质量的影响，重点对粘合剂的防水性进行了研究，叙述了瓦楞纸板用抗水粘合剂的配制及工艺过程，并与常规方法制备的粘合剂进行了性能比较，测定了抗水时间，得出了瓦楞纸板用抗水粘合剂的最佳配制比例。     

High performance LDPE/thermoplastic starch blends: a sustainable alternative to pure polyethylene

Thermoplastic starch (TPS), as opposed to dry starch, is capable of flow and hence when mixed with other synthetic polymers can behave in a manner similar to conventional polymer-polymer blends. This paper presents an approach to preparing polyethylene/thermoplastic starch blends with unique properties. A one-step combined twin-screw/single screw extrusion setup is used to carry out the melt-melt mixing of the components. Glycerol is used as the starch plasticizer and its content in the TPS is varied from 29 to 40%.Under the particular one-step processing conditions used it is possible to develop continuous TPS (highly interconnected) and co-continuous polymer/TPS blend extruded ribbon which possess a high elongation at break, modulus and strength in the machine direction. The PE/TPS (55:45) blend prepared with TPS containing 36% glycerol maintains 94% of the elongation at break and 76% of the modulus of polyethylene. At a composition level of 71:29 PE/TPS for the same glycerol content, the blend retains 96% of the elongation at break and 100% of the modulus of polyethylene. These excellent properties are achieved in the absence of any interfacial modifier and despite the high levels of immiscibility in the polar-nonpolar TPS-PE system. The 55:45 blend possesses a 100% continuous or fully interconnected TPS morphology, as measured by hydrolytic extraction. This highly continuous TPS configuration within the blend should enhance its potential for environmental biodegradation. The elongation at break in the cross direction of these materials, although lower than the machine direction properties, also demonstrates ductility at high TPS concentrations. At a glycerol content of 36% in the TPS, the blends demonstrate only very low levels of sensitivity to moisture. A high degree of transparency is maintained over the entire concentration range due to the similar refractive indices of PE and TPS and the virtual absence of interfacial microvoiding.Effective control of the glycerol content, TPS concentration and processing conditions can result in a wide variety of morphological structures including spherical, fiber-like, highly continuous and co-continuous morphologies. These various blend morphologies are shown to be the determining parameters with respect to the observed mechanical properties.This material has the added benefit of containing large quantities of a renewable resource and hence represents a more sustainable alternative to pure synthetic polymers.     

MODELING WATER LOSS DURING FRYING OF POTATO STRIPS: EFFECT OF SOLUTE IMPREGNATION

The effect of solute impregnation on water loss and oil uptake during potato strip frying was studied. Blanched potato strips were impregnated at 25°C by soaking in a solution of sucrose-NaCl-water, 20-5-75% by weight. After rinsing and air drying, strips were deep fried in sunflower oil at 160, 170 and 180°C. A control treatment, consisting of potato strips blanched but not soaked and later air dried was also conducted. Solute impregnation provided a decrease of the oil uptake. Two models, based on Fick's law were used to describe water loss during frying. The first one is the classic model with an effective moisture diffusion coefficient assumed a constant value. The second model considers that diffusion coefficient varies during the frying process. For a given frying temperature, constant diffusion coefficient for control potatoes resulted in lower values than the impregnated ones. The variable diffusivity model showed a two-stage behavior: during the first stage of frying, diffusion coefficient increased with frying temperatures, but from a given time on an inverse behavior began. This last fact was found to be related to an increase of the measured peak force needed to penetrate the potato crust.     

淀粉基干燥剂的化学性质与性能

讨论了淀粉、粗玉米粉及可以被淀粉所依附的纤维素框架的化学结构及性质,它们可能成为一系列用途广泛的干燥剂。     

Estimation of thermal diffusivity of foods using transfer functions

The effective thermal diffusivity of foodstuffs was estimated from time-temperature histories in the geometric center of samples exposed to heating and cooling processes.Transfer functions methodology was used as an alternative method to estimate the thermal diffusivity assuming that conduction was the main heat transfer mechanism. The samples were characterized as delayed first-order systems with unit gain, dead time (L) and time constant (τ).The results were compared with those obtained from the f_h value and with results reported in the literature.     

碘与淀粉的相互作用及在Vc分析中的应用

本文探讨了碘与淀粉的相互作用以及碘－淀粉显色体系的稳定性。结果表明：在碘量一定时，体系的吸光度随淀粉用量的增大而增大，最后趋向稳定；在淀粉量一定时，体系的吸光度随碘用量的增大而增大，最后亦趋向稳定。碘－淀粉显色体系很不稳定，吸光度随时间呈比较明显的下降趋势，但加入复合表面活性剂可以使显色体系的稳定性大大提高。在上述结果的基础上，我们建立了测定Ｖｃ的新方法，此法具有简单、快捷、试剂易得、灵敏度高以及对浑浊试液不必分离即可直接测定等优点。该法的灵敏度为０．２５μｇ／ｍｌ，对１μｇ／ｍｌ的Ｖｃ试液进行平行测定，１０次平行测定结果的相对标准偏差为８．８６％，加标回收率为９０．５％－９３．６％，用于番石榴汁饮料中Ｖｃ的测定，结果满意。     

热塑性淀粉加工过程的控制参数及塑化程度的表征方法

在介绍热塑性淀粉塑料加工原理的基础上,提出特殊机械能可以作为描述热塑性淀粉塑化过程的控制参数;并对表征热塑性淀粉塑化程度的各种方法进行了总结和评述。     

淀粉接枝作为精细化工设计性实验的尝试

以淀粉与丙烯酰胺接枝共聚作为精细化工设计性实验进行了尝试.从淀粉接枝的实验背景出发,设计以改变引发剂种类而形成多种实验方案的基本思路,制订了较为详细的实施方案,在实际教学中收效显著,同时,对存在的问题给予分析并提出建议.