纳米Fe3O4磁性复合丁腈橡胶用做中、高压轴封的研究

用混炼法制备纳米Fe3O4磁性复合丁腈橡胶,利用UTM摩擦磨损实验机进行摩擦磨损试验,用2206型表面粗糙度测量仪测试磨痕,用XY-I型橡胶硬度计测定邵尔A硬度.研究影响橡胶密封性能的一些因素、密封间隙与密封压力的关系等.结果表明磁性橡胶具有优良的抗磨减摩性能、自修复能力,提出一种新型的可用做中、高压或真空环境的纳米Fe3O4磁性丁腈橡胶轴封,提高轴封的压力应用范围.     

腈水合酶产生菌 Rhodococcus sp.HUST-1发酵条件的优化

Rhodococcus sp.HUST-1在Co2+的诱导下产腈水合酶,催化丙烯腈水合生成丙烯酰胺.对菌株HUST-1的产酶条件进行优化.研究表明,发酵过程中培养基中的碳氮源、诱导剂浓度以及培养条件影响腈水合酶的高效表达.在葡萄糖20 g/L、酵母粉10 g/L、Co2+0.08 mmol/L、酪氨酸0.2 g/L、pH7.0、培养温度28℃时,HUST-1所产腈水合酶总酶活达1 012.7 U,比优化前提高了47.1%.     

Regioselective Synthesis of 5-Trifluoromethyl 1,2,4-Triazoles via [3 + 2]-Cycloaddition of Nitrile Imines with CF3CN

We herein describe a general approach to 5-trifluoromethyl 1,2,4-triazoles via the [3 + 2]-cycloaddition of nitrile imines generated in situ from hydrazonyl chloride with CF₃CN, utilizing 2,2,2-trifluoroacetaldehyde O-(aryl)oxime as the precursor of trifluoroacetonitrile. Various functional groups, including alkyl-substituted hydrazonyl chloride, were tolerated during cycloaddition. Furthermore, the gram-scale synthesis and common downstream transformations proved the potential synthetic relevance of this developed methodology.     

The Impact of Nitrile-Specifier Proteins on Indolic Carbinol and Nitrile Formation in Homogenates of Arabidopsis thaliana

Glucosinolates, specialized metabolites of the Brassicales including Brassica crops and Arabidopsis thaliana, have attracted considerable interest as chemical defenses and health-promoting compounds. Their biological activities are mostly due to breakdown products formed upon mixing with co-occurring myrosinases and specifier proteins, which can result in multiple products with differing properties, even from a single glucosinolate. Whereas product profiles of aliphatic glucosinolates have frequently been reported, indole glucosinolate breakdown may result in complex mixtures, the analysis of which challenging. The aim of this study was to assess the breakdown of indole glucosinolates in A. thaliana root and rosette homogenates and to test the impact of nitrile-specifier proteins (NSPs) on product profiles. To develop a GC-MS-method for quantification of carbinols and nitriles derived from three prominent indole glucosinolates, we synthesized standards, established derivatization conditions, determined relative response factors and evaluated applicability of the method to plant homogenates. We show that carbinols are more dominant among the detected products in rosette than in root homogenates of wild-type and NSP1- or NSP3-deficient mutants. NSP1 is solely responsible for nitrile formation in rosette homogenates and is the major NSP for indolic nitrile formation in root homogenates, with no contribution from NSP3. These results will contribute to the understanding of the roles of NSPs in plants.     

Metal Free Access to Polysubstituted Pyrimidines via Nitrile Activation and [2+2+2] Cycloaddition

Tf₂O mediated intermolecular / intramolecular [2+2+2] cycloaddition between alkynes and nitriles has been developed for efficient construction of polysubstituted pyrimidines and bicyclopyrimidines. In presence of Tf₂O, aza-allene species were generated in situ through nitrile activation and subsequently participated in the [2+2+2] cycloaddition, which was fully supported by deuteration experiments. The reaction had good substrate extensibility with moderate to excellent yield including trimethylsilylalkynes. The method was utilized as a synthetic tool in the preparation of a luminescent metal complex.     

氟醚与丁腈橡胶在航空液压油中的老化行为对比研究

 以氟醚 FM-1D橡胶为研究对象，在高温的 15号航空液压油中进行了老化，对老化后的拉伸强度、拉断伸长率、压缩永久变形、质量变化、体积变化、表面及断口形貌等进行了研究，并与丁腈橡胶进行了对比。结果表明，氟醚橡胶具有优异的耐热空气及耐介质老化性能，其拉伸强度、拉断伸长率、压缩永久变形在170℃以下的液压油介质中长期老化后保持稳定，耐热性能基本保持不变，氟醚橡胶在液压油中的质量和体积变化随温度升高而增加，随时间的延长保持稳定，在质量、体积变化及稳定性方面优于丁腈橡胶胶料。另外，长时间老化过程中其压缩永久变形退化规律基本符合指数的衰减规律，但拉伸性能的退化规律则明显不符合指数的衰减规律，拉伸性能老化速度常数随温度的变化不适合采用常用的Arrhenius方程（P=Ae^-Kt）来进行寿命预测。     

Compatibilization of PA6/rubber blends by using an oxazoline functionalized rubber

The compatibilization of blends of polyamide 6 with a nitrile butadiene rubber has been investigated. The procedure consists of two steps: modification of the nitrile groups of the rubber into oxazoline in the melt through condensation of ethanolamine with formation of a molecule of ammonia, followed by use of the modified rubber as a compatibilizing precursor which is melt mixed with the polyamide to produce the compatibilized blend. The modification reaction has been detected by NMR analysis and a rheological, mechanical and thermomechanical characterization has been carried out on the all the blends. The results indicate that the modification reaction occurs but the conversion of nitrile into oxazoline is relatively low. Use of the modified rubber in the preparation of binary polyamide/rubber blends, leads to an increase in viscosity, which is typical of compatibilized systems, and to enhanced tensile, impact and thermomechanical properties. These phenomena can be explained by the formation of in situ rubber/polyamide copolymers that act as compatibilizers, due to the reaction between oxazoline and the end groups of the polyamide. The presence of residual low molecular compounds, from the modification or from the purification of the rubber worsens all of the properties and inhibits the compatibilizing effect of the modified rubber.