Flame-retardant properties and synergistic effect of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber composites

The flammability behaviors of ammonium polyphosphate/aluminum hydroxide/mica/silicone rubber (APP/Al[OH]₃/mica/SiR) ceramifying composites containing APP, Al[OH]₃, and mica are investigated by cone calorimeter test. The thermal degradation and the synergistic effect of APP/Al(OH)₃/mica/SiR composites are investigated by thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. APP/Al(OH)₃/mica/SiR composites with 25 wt% of APP, 20 wt% of Al(OH)₃, 25 wt% of mica, and 30 wt% SiR presents a much lower total heat release, the value of peak heat release rate (PHRR), the maximum average heat release rate, the longest time to ignition, and time to the PHRR (t_PHRR), compared with the flame-retardant properties from composites with filler of APP and mica or APP and Al(OH)₃ alone. The results indicate that there is an excellent synergism in APP, Al(OH)₃, and mica, which endows APP/Al(OH)₃/mica/SiR composites with both good flame retardancy and fire prevention. The study on the synergism effect between fire prevention and flame retardancy of APP/Al(OH)₃/mica/SiR composites indicates that compounds containing P-O-Al are formed due to the reaction between APP and Al(OH)₃ during combustion in the early stage and a coherent, dense, and sealed structure is formed due to the reaction in mica, phosphates, and the thermal decomposition products of SiR during combustion in the later stage.     

纯环氧酸酐树脂体系配套用国产少胶粉云母带的性能研究

主要对国产含促进剂少胶粉云母带DECJX的电气绝缘性及包扎工艺性等方面进行研究,采用该云母带制作试验定子线圈,并对定子线圈的各项性能进行测试分析。结果表明:该国产含促进剂少胶粉云母带DECJX的各项性能均达到国外同类产品的技术指标要求,生产的定子线圈各项性能优异,可逐步在高压交流电机上推广应用。     

一种新型H级少胶粉云母带的研制

该H级少胶粉云母带采用改性环氧树脂为胶粘剂,无碱玻璃布浸渍树脂后先后分别复合粉云母纸和聚酰亚胺薄膜(耐电晕处理或不耐电晕处理),经烘焙、收卷、分切、包装而成的一种电机主绝缘材料。探讨了该材料的常规电气性能及与不同类型的浸渍树脂配套绝缘性。     

云母和页岩对铁尾矿基多孔保温材料微观性能的影响

为了高附加值地利用铁尾矿,实验以铁尾矿、页岩和云母为基材并添加适量的长石和发泡剂,通过烧结的方法制备铁尾矿基多孔保温材料。采用TGA法分析云母和页岩掺量对粉料低共熔温度和烧成温度的影响,利用XRD、SEM研究云母和页岩比例的变化对铁尾矿基多孔保温材料矿物组成和形貌的影响。结果表明云母-页岩二元体系中云母含量的增加会降低试样的低共熔温度和烧成温度;页岩含量的增加能促使更多的石英参与反应生成斜长石,试样中斜长石的含量略有增加,石英则有所降低;试样内部含有大量分布均匀的气孔,最大孔的孔径约为2mm,在大气孔之间和内部存在许多小气孔。     

Experimental and theoretic studies on sound transmission loss of laminated mica‐filled poly(vinyl chloride) composites

The effects of dioctyl phthalate and inorganic filler, mica, on the sound insulation property of poly(vinyl chloride) (PVC) were investigated in this work. The stiffness and mass laws, which are the common theoretic tools to predict the soundproof properties of materials, were used to analyze the sound transmission loss (STL). The experimental results revealed that the stiffness and mass laws can describe well the sound insulation property of PVC/mica composites. The stiffness and surface density are important factors influencing the improvement of STL. With the increase of content of mica, STL and resonance frequency, f_mn, of PVC/mica composites increase. Moreover, the change of STL in the stiffness‐ controlled region is more obvious than that in the mass‐controlled region, because the addition of mica in PVC leads to a greater increase in the stiffness. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Atomically Thin Mica Flakes and Their Application as Ultrathin Insulating Substrates for Graphene

By mechanical exfoliation, it is possible to deposit atomically thin mica flakes down to single‐monolayer thickness on SiO₂/Si wafers. The optical contrast of these mica flakes on top of a SiO₂/Si substrate depends on their thickness, the illumination wavelength, and the SiO₂ substrate thickness, and can be quantitatively accounted for by a Fresnel‐law‐based model. The preparation of atomically thin insulating crystalline sheets will enable the fabrication of ultrathin, defect‐free insulating substrates, dielectric barriers, or planar electron‐tunneling junctions. Additionally, it is shown that few‐layer graphene flakes can be deposited on top of a previously transferred mica flake. Our transfer method relies on viscoelastic stamps, as used for soft lithography. A Raman spectroscopy study shows that such an all‐dry deposition technique yields cleaner and higher‐quality flakes than conventional wet‐transfer procedures based on lithographic resists.     

产业化生产优质系列云母珠光颜料

常州涂料化工研究院以优质白云母为原料,开发出净化分级、云母活化、四氯化钛控制水解包膜 和连续化煅烧等技术,在100t/a工业装置上生产出系列优质云母珠光颜料,质量接近国外名牌产品水平,产品 性价比高,80％以上用来出口。     

Adsorption of As(III), As(V), Cd(II), Cu(II), and Pb(II) from Aqueous Solutions by Natural Muscovite

Various parameters were tested for the application of natural muscovite (NM) in the removal of metals from aqueous solutions: contact time, pH, ionic strength, and initial metal concentrations. Kinetic studies showed that the pseudo-second-order model explains well the sorption process. The adsorption of metals was greatly influenced by solution pH but not by ionic strength. The results from isotherm studies agreed more with the Freundlich isotherm model than with the Langmuir isotherm model. The adsorbed quantity of metals by NM was lower than that by the purified mica. These results suggested that the composition and surface characteristics of natural minerals may seriously influence applications for water purification.     

钠离子交换法从黑云母中提钾及水钠云母的电化学性能

为了解决我国钾资源短缺的问题,从难溶性钾矿物中提取可溶性钾元素的技术需要被进一步研究。以钾含量相对较高的黑云母为研究对象,通过钠离子交换法从黑云母中提取出可溶性钾元素并制备出水钠云母负极材料。在80 ℃的水热反应温度下,钾离子与钠离子发生交换,通过过滤反应液从滤液中获取可溶性钾盐并得到水钠云母负极材料。X-射线衍射结果表明:反应后的云母层状硅酸盐结构未被破坏,8 h内提钾率高达92.3%。通过电化学工作站测定黑云母及提钾后水钠云母的电化学性能,在0.4 A/g电流密度下进行恒流充放电,测得水钠云母负极材料的首次放电比电容为9.8 F/g,较黑云母原矿的电化学性能有明显的提高。     

云母钛珠光颜料制备过程中TiCl_4与尿素水解反应动力学

测定均匀沉淀法制备云母钛珠光颜料过程中TiCl4与尿素水解反应浓度的变化规律,建立其水解动力学方程.通过实验研究,得出TiCl4水解反应的级数a为1.3级,其活化能Ea1为284.01kJ/moL;尿素水解反应的级数a为零级,其活化能Ea2为131.03kJ/moL.通过尿素与TiCl4的动力学方程进行分析,得出一次加入尿素,连续加入钛盐的新加料方法.