Electrical properties of an insulating varnish

A systematic dielectric study was carried out over a frequency range 60 Hz–300 kHz and at temperatures between 5 and 90°C on dehydrated castor oil mixed with different concentrations of styrene monomer to produce an insulating varnish. The volume resistivity was also studied. The results show that, when dehydrated castor oil is mixed with 10% styrene content by weight of the oil, epoxidised and then chemically treated with melamine resin and other additives, a varnish is produced with favourable electrical insulation properties.     

Ceramer coatings from castor oil or epoxidized castor oil and tetraethoxysilane

New inorganic-organic hybrids were synthesized through the reaction of castor oil (CO) or epoxidized castor oil (ECO) with tetraethoxysilane (TEOS). The mass proportions of ECO/TEOS varied from 90∶10 to 60∶40, and films of the material were thermally cured. An IR spectroscopy analysis was performed, and macro- and microscopic properties such as adhesion, hardness, swelling in toluene, microstructure (scanning electron microscopy), and T _g were investigated as a function of the proportion of their inorganic-organic precursor. Morphologic studies showed that the hybrid films were homogeneous when lower proportions of the inorganic precursors were used. Hardness and tensile strength increased with TEOS concentration, whereas swelling in toluene decreased with TEOS concentration. Good adhesion was observed throughout the hybrid series.     

Bacterial contents of the anal and castor glands of beaver (Castor canadensis)

Bacterial contents of both the anal gland and castor gland of the beaver (Castor canadensis) were determined. Using our culture methods, no bacteria were isolated from the castor glands, but the anal gland contained high numbers of the aerobeEscherichia coli and the anaerobeBacteroides fragilis. The latter may be represented by several variants but facilities were not available for advanced anaerobic analysis. The relative numbers of each bacterial group and the group present were constant regardless of sex, age class, or colony of beaver. The bacterial fermentation hypothesis is rejected for castor gland section but remains possible for anal gland secretions based on variations seen inB. fragilis. The role of the products of both the castor gland and anal gland are discussed in relationship to scent communication in beaver.     

Ethanolysis of castor and cottonseed oil: A systematic study using classical catalysts

Several classical catalytic systems for the transesterification reaction have been used to produce FA ethyl esters (FAEE) from castor and cottonseed oils The effects of the amount and nature of the catalyst, and of the reaction temperature, on the yields of FAEE were determined. The most efficient transesterification of castor oil was achieved in the presence of methoxide and acid catalysts, whereas for cottonseed oil, which has a composition that is much more similar to most vegetable oils than is castor oil, the highest yields of FAEE were obtained following base-catalysed ethanolysis.     

天然原料合成水性聚氨酯的研究

采用天然的蓖麻油与聚醚(N 210)、聚乙二醇(Mn=1000)、甲苯二异氰酸酯、二乙烯三胺、环氧氯丙烷、马来酸酐等为原料,通过丙酮法制得稳定的水性聚氨酯乳液。提出了聚合反应的机理,研究了亲水单体对聚氨酯乳液的粘度、稳定性、乳液成膜的干燥时间、膜的耐水性的影响。结果表明,通过改变亲水单体的含量,可以制得稳定、适用的聚氨酯乳液。     

化学改质蓖麻油的流变性能和摩擦学特性研究

通过对天然蓖麻油进行化学改质，利用异构化反应增加分子侧碳链的长度，以提高其粘度指数和降低其倾点；考察了改质蓖麻油的流变性能和摩擦化学性能。实验结果表明，天然蓖麻油经化学改质后流变性能得到了较大改进，其抗磨减摩性能优于同粘度的矿物油，相当于季戊四醇酯或癸二酸二异辛酯。     

Preparation,morphology, and thermoelectric property studies of BaTiO3 superfine fiber/castor oil polyurethane‐based IPN nanocomposites

A series of castor oil polyurethane/poly(methyl methacrylate) interpenetrating polymer networks (IPNs) and gradient IPNs, cured at room temperature, were prepared by a simultaneous IPN method. The polymerization processes were traced through IR techniques; results for the morphology and miscibility among multiple phases of materials, obtained by transmission electron microscopy, indicated that the systems belonged to graft‐mode IPNs, and the domains between two phases were controlled on a nanometer scale. Thermomechanical analysis detection results showed that through interpenetration between networks, the glass‐transition temperatures of the systems could be linked up effectively. Furthermore, the systems were combined with selected barium titanate superfine fibers. The composite techniques were determined, and the thermoelectric and mechanical properties were examined in detail. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 709–715, 2002; DOI 10.1002/app.10024     

Castor‐Oil‐Based Waterborne Polyurethane Dispersions Cured with an Aziridine‐Based Crosslinker

Castor‐oil‐based anionic PU dispersions are post‐cured using a multiaziridine‐based crosslinker CX‐100. Thermal and mechanical properties of the resulting films are studied by DMA, DSC, TGA, and tensile tests. Mechanical properties are dramatically improved by the crosslinker. For example, the Young's modulus and tensile strength increase from 14.5 to 125 MPa and 13.1 to 18.1 MPa, respectively, when the aziridine fraction increases from 0 to 100%. The onset decomposition temperature of the films, T₅, increases from 162 to 209 °C, indicating a significant increase in the thermal stability as the amount of aziridine is increased. This work provides an effective way of curing biorenewable anionic PU dispersions to prepare high performance, environmentally friendly coatings.

     

新型汽车防锈底漆蜡的合成研究

以油脂、甘油、己二酸和1,6己-二胺等为主要原料,采用脂肪酸溶剂法和酰胺化改性,合成出了能够用于汽车防锈底漆的韧性酰胺蜡。结果表明其最佳合成工艺条件为:酯化温度200℃,酯化时间3 h;酰胺化温度190℃,酰胺化时间3 h;反应物最佳配比为油脂质量分数10%,m(己二胺实际添加量)∶m(己二胺理论添加量)=1∶1。在该工艺条件下产品滴熔点大于100℃,酸值与胺值均小于10 mg(KOH)/g,蜡膜明度L*大于80,表面平整细密,反复弯折不脱落、不断裂,达到了汽车防锈底漆的性能要求。     

蓖麻毒蛋白提取

介绍了蓖麻毒蛋白提取的方法。通过对不同条件下实验所得的蓖麻毒蛋白提取率，进行比较、分析，得到提取率较高的方法和条件。