Ring‐Opening/Expansion Rearrangement of Cycloprop[2,3]inden‐1‐ols Catalyzed by p‐Toluenesulfonic Acid

A divergent approach to generate either 1‐hydroxymethylindenes (which could then be converted to benzofulvenes through a dehydration reaction) or naphthalenes by the rearrangement of cycloprop[2,3]inden‐1‐ols is reported. The effect of the cyclopropyl ring substitution pattern on ring‐opening/expansion rearrangements of the substrates was systemically studied.

     

Synthesis of Chiral Cyclopropyl Carbocyclic Purine Nucleosides via Asymmetric Intramolecular Cyclopropanations Catalyzed by a Chiral Ruthenium(II) Complex

The synthesis of chiral cyclopropyl carbocyclic purine nucleoside analogues via the highly enantioselective intramolecular cyclopropanation reactions has been reported. With a chiral ruthenium(II)‐phenyloxazoline complex as the catalyst, cyclopropyl carbocyclic purine nucleoside analogues containing three contiguous stereocenters were obtained with up to 99% yield and 99% ee. Furthermore, a chiral cyclopropyl carbocyclic adenosine nucleoside having anti‐BLV activity could be synthesized in a concise manner using this strategy.

     

Multifunctional liquid‐like graphene@fe3o4 hybrid nanofluid and its epoxy nanocomposites

Novel multifunctional graphene@Fe₃O₄ hybrid nanofluid with liquid‐like behavior at room temperature and low viscosity (5.5 Pa.s at 25°C) has been developed by using GO@Fe₃O₄ as a core, sulfuric acid‐terminated organosilanes as corona, and polyether amine as canopy. The obtained nanofluid has been extensively characterized by various analytical techniques. The content of graphene@Fe₃O₄ reaches up to 13.78 wt% in the hybrid nanofluid, which is a superparamagnetism material with specific magnetization of 0.39 emu/g. In addition, it shows excellent dispersion and exfoliation in solvents and polymer matrixes. It is then compounded with an epoxy resin for the development of liquid‐like graphene@Fe₃O₄ hybrid nanofluid/epoxy nanocomposites. It is found that liquid‐like graphene@Fe₃O₄ hybrid nanofluid/epoxy nanocomposites demonstrate better mechanical property than those of unmodified graphite/epoxy nanocomposites at the same fraction. For example, the multifunctional liquid‐like graphene@Fe₃O₄ hybrid nanofluid at 1.5 wt% improves the impact toughness of epoxy by 125%. This new interface modification also enhanced the T_g of neat epoxy from 98.37 to 129.46°C. POLYM. COMPOS., 37:3474–3485, 2016. © 2015 Society of Plastics Engineers     

航空含氟树脂电缆燃烧及火蔓延特性研究

使用锥形量热仪和电缆垂直燃烧实验仪,对配有聚四氟乙烯(PTFE)护套和聚全氟乙丙烯(FEP)护套的两种航空含氟树脂电缆的燃烧和垂直火蔓延特性进行了研究.在三个热辐射强度下对航空含氟树脂电缆进行实验,比较分析了热释放速率、质量损失和烟气产生速率三个主要燃烧性能参数的变化规律,并对反应过程进行了分析.实验结果表明,绕包工艺...     

滑动轴承聚合物基自润滑材料的开发与应用进展

介绍聚四氟乙烯、聚醚醚酮、聚酰胺、聚甲醛、聚酰亚胺等滑动轴承用自润滑材料的研究开发情况、性能特点及用途,重点介绍了聚醚醚酮基复合材料的共混改性、纤维增强改性、填充改性和表面改性等方面的研究进展和应用情况,并提出了自润滑材料今后的发展方向。     

中国彩绘瓷影响下的日本古九谷风格彩绘瓷的发展过程

论述了日本古九谷风格的彩绘瓷器,是在借鉴中国明末清初彩绘瓷器技法的基础上产生并发展的,同时又融入了本民族的智慧,有了自己的独特风格。     

对氨基苯硫酚的合成和表征

以对硝基氯苯为原料,合成对氨基苯硫酚。根据亲核取代和还原反应的机理,有针对性的选择多硫化钠作为取代还原的反应试剂,在温度90℃,反应5h和还原温度150℃,反应3h,产率为85.4%。产品外观为白色粉末,熔点为39.1℃～40.9℃。     

共混聚合物界面相容性研究进展

综述了改善共混物界面相容性的3种方法。提高大多数不相容聚合物相容性的方法主要是加入嵌段或接枝共聚物等增容剂;对其中一相进行化学改性的方法在生物高分子领域有较多的应用;由于无机纳米粒子有增强增韧的作用且较容易获得,因此,加入无机纳米粒子改善共混聚合物相容性的方法具有很大的发展空间。     

WLAN与GSM／TD—SCDMA网络融合策略研究

数据业务需求的迅猛发展,使得对IP和高速数据业务的支持成为移动通信系统的发展方向,充分利用2G／TD网络与WLAN的特点进行融合是解决当前数据业务需求现状的有效方法之一。本文从WLAN与2G／TD移动通信系统的融合需求入手,比较了融合方案,讨论了网络的融合演进策略,并对演进中所采用认证及计费策略进行了分析。     

Polyaniline/carbon black composite as Pt electrocatalyst supports for methanol oxidation: Synthesis and characterization

Core/shell composites of polyaniline (PANI) and Vulcan XC‐72 Carbon (VC), in which the carbon represents the core and PANI forms the shell, were synthesized by in situ chemical oxidation polymerization. Platinum (Pt) particles were then deposited on the PANI/VC composites by chemical reduction method. The highest conductivity is obtained when a mass ratio of PANI/VC equals to 0.28, as proved by Fourier transform infrared spectra. And it is also proved that there are some reactions happened between PANI and VC. Scanning electron microscope, transmission electron microscope, and X‐ray diffraction measurements were performed to analyze their structure and surface morphology. It has been observed that the Pt particles are smaller in size and more uniformly distributed on these composite supports than on pure VC supports, considered as a reference. Methanol oxidation performed on the electrode modified by such a composite catalyst has been measured by cyclic voltammogram focusing on the attenuation of methanol oxidation current after 200 cycles. The attenuation degree for the composite catalyst is only one‐third of the one measured for a simple Pt/VC catalyst. It is proved that the composite catalyst better resist carbon monoxide poisoning in comparison with the Pt/VC catalyst, which may be due to the synergetic effects between the composite support and the Pt catalyst. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010