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1.
S-148芳醇不饱和聚酯树脂耐腐蚀机理研究   总被引:1,自引:0,他引:1  
合成了S-148芳醇不饱和聚酯树脂,研究了S-148树脂浇铸体和玻璃钢于不同温度下在不同介质中的耐酸、碱、盐腐蚀性能,并探讨了其耐腐蚀机理。结果表明,S-148树脂具有优异的耐腐蚀性能,可用作耐腐蚀制品的基体树脂。  相似文献   
2.
六水氯化镁的溶解度是镁盐综合利用的重要基础数据。采用静态平衡法测定了六水氯化镁在1,2-丙二醇、1,3-丙二醇、1,3-丁二醇、一缩二乙二醇、二缩三乙二醇、一缩二丙二醇6种多元醇中的溶解度(278.15~328.15 K)。实验结果表明,六水氯化镁在6种多元醇中的溶解度均随着温度的升高而增大,其中在一缩二乙二醇中的溶解度最大,在二缩三乙二醇中的溶解度随着温度的变化较其他多元醇变化更为明显。使用Apelblat方程、λh方程、Van′t Hoff方程和多项式方程对溶解度数据进行了关联,结果良好,其中Apelblat方程和多项式方程拟合结果优于其他方程。利用Van′t Hoff方程计算了6种体系的溶解焓、溶解熵和吉布斯自由能。这些结果对镁盐的分离提取及镁基功能材料的制备具有重要的参考价值。  相似文献   
3.
以含有不同离子基团的聚酯多元醇为软段,采用丙酮法合成了一系列水性聚氨酯乳液。研究了不同硬段结构和硬段含量和扩链剂对其干膜物理机械性能和吸水率的影响。  相似文献   
4.
(接上期第 2 3页 )3 膜分离Doraietal[16] 通过超滤除去低相对分子质量级份 ,使聚醚多元醇 ,尤其是聚四氢呋喃多元醇 ,具有较窄的分布 (Mw∶Mn=1 .2~ 1 .8)。该方法通过对多分散的熔融聚合物实施物理分级 ,达到降低相对分子质量分布的目的 ,可使最终产物的相对分子质量为 40 0~ 40 0 0 ,分散度为 1 .2~ 1 .8。该方法首先需要准备 1套交叉流动的膜分离系统 ,采用渗透膜或半渗透膜 ,膜的一边是滞留物 ,另一边是超滤液。然后 ,在起始聚合物的熔点以上 ,分解温度以下 ,且温度不大于膜的熔融和分解温度 ,将起始聚合物熔融 ,并流入该系统中…  相似文献   
5.
双金属氰化物催化剂的研究进展   总被引:3,自引:0,他引:3  
综述了近年来双金属氰化物(DMC)催化剂的研究进展,指出DMC催化剂是一类用于环氧化物的高效催化剂,与传统的环氧化物催化剂相比,其制得的聚醚多元醇具有分子量高、不饱和度低、分子量分布窄、平均官能度高等优点。但该催化剂在应用过程中仍存在一些缺点。针对这些缺点,国内外的高校、企业已进行了大量的改性研究工作。  相似文献   
6.
A series of soybean oil phosphate ester polyols (SOPEP) was prepared by reaction of fully epoxidized soybean oil with phosphoric acid and simultanoeous hydrolysis in the presence of a polar solvent. The polyols were characterized by determination of acid value, oxirane number, hydroxyl value, molecular weight (GPC), and FTIR spectra. These polyols with varying amounts of acid phosphate groups could be self-emulsified to form aqueous dispersions after neutralization with organic base. These aqueous dispersion showed varying degrees of stability and their appearance ranged from opaque dispersions to translucent to clear solutions. Waterborne coating compositions were prepared using these aqueous dispersions as principal components and their thermally cured film properties were studied. it was found that by careful selection and formulation, SOPEPs can be successfully used for low-VOC waterborne coating formulations. SOPEPs with 3.5% phosphate ester content showed visibly superior corrosion resistance properties.  相似文献   
7.
混杂增强聚氨酯复合硬质泡沫塑料的研制   总被引:5,自引:0,他引:5  
系统介绍混杂增强聚氨酯复合硬质泡沫塑料的制备情况,详细分析聚氨酯硬质泡沫塑料制备过程中的工艺问题,表征与分析其结构与性能,着重分析偶联剂对填充物增强性能的影响以及填充物含量对聚氨酯硬质泡沫塑料吸水性能的影响,介绍聚氨酯硬质泡沫塑料的应用,最后指出其发展前景。  相似文献   
8.
A series of liquid polyester polyols from adipic acid (AA), phthalic anhydride (PA), ethylene glycol, propanediol‐1,2, and trihydroxymethylpropane, varying in the molar ratio of PA to AA, were prepared. The effects of the o‐aromatic ring in the molecular chain, which came from PA, on the viscosity, glass‐transition temperature, and thermal degradation temperature of the polyester polyols were studied with viscometry, differential scanning calorimetry, and thermogravimetry. The intrinsic viscosity and glass‐transition temperature increased with the concentration of the o‐aromatic ring increasing. The temperature of the maximum thermal degradation rate for aliphatic polyester polyols was 434.20°C. Two steps of thermal degradation were found when there were o‐aromatic rings in the molecular chain. One thermal degradation temperature was 358.36–360.48°C, and the other was 412.85–427.18°C. Polyester polyols with o‐aromatic rings had higher stability at lower temperatures (<240.00°C). However, aliphatic polyester polyols had higher stability at higher temperatures (300.00–480.00°C). The activation energy and order of degradation were calculated from thermogravimetric curves. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1617–1624, 2002  相似文献   
9.
An empirical correlation is presented for the estimation of critical micellization concentrations (CMC) and critical micellization temperatures (CMT) for poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) copolymers in aqueous solutions. The CMC and CMT are expressed as a function of the polyol molecular weight, composition, and temperature (for CMC determination) or concentration (in the case of CMT). The correlation was developed from experimental CMT data for a set of 12 polyols that covered a wide range of molecular weights (2900–14600) and poly(ethylene oxide) contents (30–80 wt%) and is based on a simple expression for the standard free energy of micellization. Such a correlation should be useful to practitioners of the field as it allows easy prediction of CMC and CMT for a wide range of polyols with a minimal number of input parameters.  相似文献   
10.
This review presents the state‐of‐the‐art concerning the application of natural and artificial high‐intensity sweeteners, fructans and bulking agents such as polyols as sugar replacers in sweet‐baked goods and their effects on product characteristics. The recent much publicised attention given to weight gain of the population and its consequences on the occurrence of diet‐related diseases in developed countries has influenced the food manufacturers attempts to provide the consumer with reduced energy products. The replacement of sucrose in sweet bakery products by alternative natural or artificial sweeteners can be a challenging issue. Sucrose as a main ingredient in sweet bakery products contributes, aside from providing sweetness, to numerous processing and product characteristics. Intense sweeteners have a high sweetness compared with sucrose but lack in their contribution to the body of the product, whereas the replacement of sucrose with bulking sweeteners may result in products with a similar body but a lack in taste and flavour.  相似文献   
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