The effect of modifiers on the stability of a vinyl acetate/ethylene copolymer dispersion

This paper examines the effect of modifiers on the stability of a vinyl acetate/ethylene copolymer dispersion adhesive upon aging. Eighteen common modifiers were added to a well-characterized vinyl acetate/ethylene copolymer dispersion (Dur-O-Set^® E-150) in known concentrations and dry-film samples were subjected to 16–17 years of dark aging and seven to eight years of light aging. Yellowing, pH, gloss, swelling, cohesive strength, and flexibility were monitored for changes upon aging. Generally, the neat Dur-O-Set^® E-150 (no additives) was found to become acidic on aging, but was fairly resistant to yellowing. It also swelled substantially in toluene, was of high gloss, medium strength, and flexible, and remained so on aging. No modifier was found to improve these properties. Various solvents, wetting agents, and thickeners did not alter the properties by much, while plasticizers, freeze-thaw stabilizer, glycerin, and certain fillers had a more negative effect.     

醋酸钙镁冰雪融化剂的制备及融冰效果小试

本文制备了醋酸钙美(CMA) 冰雪融化剂并在实验室小试了其融冰能力,并与氯化钠和氰化钙进行了比较。结果表明,CMA组成和环境温度对CMA融冰效果有很大影响。CMA适宜在环境温度-11℃以上使用,CMA中钙镁比为7:3时,融冰能力可以达到氯化钠和氯化钙的75％～80％,是一种优良的冰雪融化剂。     

磷钨杂多酸催化合成乙酸正己酯

以磷钨杂多酸为催化剂,通过乙酸和正己醇的酯化反应合成了乙酸正己酯,并对影响酯化率的因素进行了研究.结果表明:反应的最佳条件为:乙酸为0.1 mol时,醇酸物质的量比为1.4,催化剂用量为0.3 g,带水剂为15 mL,在温度为110~130℃下,反应30 min,酯化率可达99.6%以上.     

3,7-二甲基-2-十三碳醇乙酸酯的合成——松叶蜂Diprion pini性信息素活性组分

对松叶蜂 diprion pini性信息素活性组分 3,7-二甲基 -2 -十三碳醇乙酸酯的全合成进行了研究 .以丙二酸二乙酯和 2 ,3-环氧丁烷为原料 ,分别合成了两个重要结构单元—— 2 -甲基 -1-辛烷基锂和 3,4-二甲基 -γ-丁内酯 .2 -甲基 -1-辛烷基锂与 3,4-二甲基 -γ-丁内酯反应 ,得到的酮醇再经黄鸣龙还原 ,得到 3,7-二甲基 -2 -十三碳醇 ,经酯化 ,得到 3,7-二甲基 -2 -十三碳醇乙酸酯     

一水合硫酸氢钠催化合成乙酸正己酯

研究了以硫酸氢钠为催化剂，乙酸和正己醇为原料合成乙酸正己酯，并考察了反应条件对酯化率的影响．结果表明，在适宜条件下其酯化率可达97．6％．     

稀土复合固体超强酸SO_4~(2-)/TiO_2/Ce~(4+)催化合成乙酸环己酯及动力学研究

研究了以稀土复合固体超强酸SO42-/TiO2/Ce4+为催化剂合成乙酸环己酯的反应,在反应温度分别为100℃、110℃、120℃下,测出酯化反应的动力学参数,建立了动力学方程,并与无催化剂作用下合成乙酸环己酯反应的活化能及动力学方程进行了比较.实验结果表明,该催化酯化反应的优化合成条件是:乙酸用量为0.262 1mol时,醇酸摩尔比为1.5:1,催化剂用量为1.0g,带水剂环己烷的加入量为12mL.稀土复合固体超强酸SO42-/TiO2/Ce4+可使反应的活化能明显降低,是合成乙酸环己酯的有效催化剂.     

丙烯酸酯和醋酸乙烯酯二元共聚物的合成、表征与降凝助滤效果

主要介绍了丙烯酸酯和醋酸乙烯酯二元共聚物（简称AV）类柴油降凝剂的合成和降凝助滤效果。AV柴油降凝剂，是以丙烯酸酯、醋酸乙烯酯为原料，以甲苯为溶剂，以偶氮二异丁腈为引发剂，恒温聚合制得。该剂对胜利油田胜华炼油厂0＃柴油的纯降凝度可达19℃，冷滤点降低可达9℃，对东明、濮阳、汤阴、大庆等地的柴油也有很好的降凝和降冷滤点效果。     

Effects of short-term hormone replacement on atherogenic indices in Indian postmenopausal women

Indian ethnicity by itself is a strong risk factor for development of CAD in Indian postmenopausal women due to lower HDL levels as compared to Whites and women of oriental origin. We evaluated and compared the short-term effects of menopause, estrogen replacement therapy and combined estrogen and progestin replacement therapy on various atherogenic indices. 40 postmenopausal women, both surgical and natural (20 each) were selected. 10 surgical postmenopausal women were given 0.625 mg conjugated estrogens daily for 6 months and 10 natural postmenopausal women were given 0.625 mg conjugated estrogen with 2.5 mg medroxyprogesterone acetate daily. 20 women were included in the control group and given placebo. Fasting venous blood samples were analyzed for extended lipid profile and calculated atherogenic indices before starting the therapy and after 1,3 and 6 months. LDL and Apolipoprotein B increased (p<0.05) and those of Apolipoprotein A1 and HDL decreased in the control groups. In both the study groups levels of serum cholesterol and LDL decreased (p<0.05) and those of HDL and Apolipoprotein A1 increased (p<0.01). LDL/HDL, Apo B/ApoA1, Total Cholesterol/HDL decreased significantly (p<0.05) in both the study groups compared to the control groups. The effect of estrogen alone was more significant as compared to combination therapy. Log Triglycerides (TG)/HDL ratio showed a decrease in women on estrogen alone but the difference was not significant. Our study confirms that short term HRT has a favorable effect on atherogenic indices in Indian postmenopausal women.     

扁担杆乙酸乙酯部位镇痛作用

研究扁担杆乙酸乙酯部位的镇痛作用。采用化学方法制备扁担杆乙酸乙酯部位。采用热板法和醋酸致小鼠扭体实验观察乙酸乙酯部位对小鼠的镇痛作用。结果发现低浓度扁担杆乙酸乙酯部位能能明显提高小鼠痛域值并减少醋酸致小鼠扭体次数;中浓度乙酸乙酯部位可以减少醋酸致小鼠扭体次数,但对小鼠痛域值并没有影响。实验结果提示扁担杆乙酸乙酯部位具有一定镇痛作用。     

无机盐催化合成乙酸正丁酯的研究

实验研究了FeCl3·6H2O、Fe(So4) 3·XH2O、CuCl2·2H2O、NaHSO4·H2O、TiSO4、SnCl4·5H2O、AlCl3·6H2O、ZnSO4·7H2O、CuSO4·2H2O等几种无机盐对乙酸与正丁醇酯化反应的催化剂的催化性能的影响.结果表明:FeCl3·6H2O、Fe(SO4)3·XH2O、CuCl2·2H2O、NaHSO4·H2O、TiSO4、SnCl4·5H2O、AlCl3·6H2O都是较好的催化剂,同时,研究了以上几种无机盐催化剂合成乙酸正丁酯的最佳反应条件、特点并得出用以上催化剂重新组合的FeCl3-CuCl2,Fe(SO4)3-CuCl2按质量的2:1组合成混合催化剂重复性更好.