基于动态硼酸酯键改性黄原胶的性能

基于苯硼酸聚合物可以与存在于黄原胶糖环单元结构中的伯、仲醇羟基通过硼酸酯键形成动态共价微交联结构的性质对黄原胶进行改性。以偶氮二异丁基脒二盐酸盐（AIBA）为引发剂，通过水相自由基聚合，制备了不同共聚比的丙烯酰胺（AM）、N-(3-二甲氨基丙基)丙烯酰胺（DMAPAM）和3-丙烯酰胺基苯硼酸（AMBB）的三元共聚物P(AM-co-DMAPAM-co-AMBB)。通过1H NMR、FTIR、元素分析和光散射对聚合物结构及相对分子质量进行了表征，并对其与黄原胶复配体系的增黏性、流变性、抗老化性及抗干扰性进行了评价。结果表明：P(AM-co-DMAPAM-co-AMBB)与黄原胶复配后对黄原胶溶液具有明显的增黏性，其中苯硼酸单体的摩尔比为1.0 mol%的聚合物对黄原胶溶液的增黏幅度达43.8%，在8074 mg/L的矿化水中增黏幅度高达56.4%，且复配体系具有良好的抗老化降解性，对乙二醇和1,3-丙二醇具有较强的抗干扰性。     

Evidence of an oviposition stimulant for peachtree borer

Peachtree borer (PTB) cocoons, peach tree bark, and a mixture of frass and gum obtained arount PTB wounds were extracted with organic solvents of increasing polarity. Female PTB moths,Synanthedon exitiosa (Say), laid the greatest number of eggs on filter paper substrates treated with acetone extracts of PTB cocoons, ethyl acetate extracts of peach tree bark and acetone extracts of frass and gum mixtures. The extracts of cocoons or frass and gum mixture were separated by liquid chromatography and thin layer chromatography.Synanthedon exitiosa (Say).Mention of a commercial or proprietory product does not constitute an endorsement of this product by the USDA.     

新型加成型硅橡胶灌封胶的研究

本文合成了两种新型加成型硅橡胶：ＴＡＳ硅橡胶和ＭＤＡＳ硅橡胶。与通常使用的乙烯基加成型硅橡胶相比，ＴＡＳ或ＭＤＡＳ硅橡胶的固化条件与之相似，但ＴＡＳ－ｐｔ和ＭＤＡＳ－ｐｔ固化体系对许多能阻滞乙烯基加成型硅橡胶固化的物质不敏感。另一方面，ＴＡＳ－ｐｔ和ＭＤＡＳ－ｐｔ固化体系对许多材料（尤其对金属）呈现良好的粘接性能，且当样品浸于水中１５天后，仍保持其粘性。上述性能，使之具有许多用途。本文还讨论了ＴＡＳ和ＭＤＡＳ生胶的合成方法，以及影响ＴＡＳ、ＭＤＡＳ固化的若干因素。     

黄原胶的结构、性能与应用

简要介绍了黄原胶的结构、性能;综述了它在化学工业及食品工业中的应用;重点论述了黄原胶作为悬浮剂、乳化剂、稳定剂、增稠剂等在日用化学工业中的应用,具有优良的悬浮性、乳化性、流变性、热稳定性及酸、碱稳定性;最后指出了我国在黄原胶应用方面的不足及以后的发展方向。     

Studies on graft copolymerization of 4‐vinylpyridine onto guar gum

Graft copolymerization of 4‐vinylpyridine (4‐VP) onto guar gum (GOH) using potassium monopersulfate (PMS)/thioacetamide (TAA) as a redox pair was studied in an aqueous medium under inert atmosphere. The concentration of potassium monopersulfate and thioacetamide should be 1.0 × 10^?2 and 5.0 × 10^?3 mol dm^?3, respectively, for highest grafting ratio and efficiency. Efficient grafting was observed at 19.25 × 10^?2 and 4.87 × 10^?2 mol dm^?3 concentration of 4‐vinylpyridine and sulfuric acid, respectively. The optimum temperature for grafting is 30°C. As the time period of reaction is increased, the grafting ratio increases, whereas efficiency decreases. The plausible mechanism of grafting has been suggested. A sample of guar gum and guar‐ g‐4‐vinylpyridine were subjected to thermogravimetric analysis with the objective of studying the effect of grafting 4‐vinylpyridine on the thermal stability of guar gum. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2380–2385, 2002     

Transport of Gellan Gum Microbeads in Soil Columns of Various Grain Size Distributions

The transport of gellan gum microbeads as potential cell carriers was investigated in horizontal columns packed with different grain size classes of gravel (2–16 mm) and sand (0.25–2 mm). A suspension of microbeads was pulsed into each column for 6 h, followed by injection of water for 42 h. In general, the total amount of microbeads travelling across a given section of the column increased with injection time but decreased towards the column outlet, varying as a direct function of grain size. The results of this study demonstrate the feasibility of the transport of gellan gum microbeads through medium sand to medium gravel across distances up to 110 cm.     

季铵盐型阳离子瓜尔胶的制备

以瓜尔胶为原料,3-氯-2-羟丙基三甲基氯化铵为醚化剂,氢氧化钠为催化剂,乙醇为溶剂,制备了季铵盐型阳离子瓜尔胶,考察了乙醇浓度、醚化剂用量、pH值、反应温度、反应时间对季铵盐型阳离子瓜尔胶取代度和反应效率的影响,得出较佳制备条件为:乙醇质量分数为85%,pH11.0,反应温度70℃,反应时间4h,在较佳条件和醚化剂与瓜尔胶质量比为7∶100的条件下,阳离子瓜尔胶取代度为0.1651,反应效率86.79%.     

微电解-混凝沉淀-生化法处理松脂加工废水

介绍了采用微电解-混凝沉淀-生化法处理松脂加工废水的调试操作．在微电解处理过程中,当进水CODcr为976～2012mg／L时,出水CODcr为262～296mg／L,CODcr的平均去除率为79．3％;在生化处理过程中,当进水CODcr为342—415mg／L时,出水CODr,控制在100mg／L以下,CODcr的平...     

液晶微囊化制备及光学性能的研究

为解决液晶分子在应用时封装复杂、难以成膜的问题,采用复凝聚法,利用液晶为囊芯材料,阿拉伯胶与明胶为璧材,对向列液晶5CB进行了微囊化.分析了溶液pH值、反应温度、反应时间、壁材浓度、搅拌速率等因素对微胶囊产品质量的影响.通过偏光显微镜和紫外分光光度计对形貌及包囊情况进行表征.研究结果表明:制备液晶微胶囊的最佳工艺条件为明胶与阿拉伯胶浓度均为2%,且两者质量比为1:1,pH值为4.0,搅拌速度为1 500r·min-1,反应温度为55℃,凝聚时间为15~20min,固化温度为10℃,固化时间60min.     

Fine grinding of thermoplastics by high speed friction grinding assisted by guar gum

High speed friction grinding has been used to grind plant and food substances in water but never been explored for grinding of thermoplastics like polylactic acid (PLA), low and high density polyethylene and polypropylene. Such grinding was investigated in this work and was made possible by using 0.5% guar gum solution instead of just water because increasing the viscosity of water reduced their settling and the speed of passing through the grinder. Tensile, flexural, and impact strengths of the plastics were studied and higher grinding efficiency of PLA could be explained by its low elongation-at-break compared to low density polyethylene, high density polyethylene, and polypropylene. The microplastics (2000–45 μm) were studied for mass and particle size distributions and by scanning electron microscopy, ¹³C CP/MAS NMR, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. In addition, viscosity of guar gum and contact angles was measured. This new technology can produce finely ground microplastics (710–45 μm) for a variety of applications.