钨/二氧化硅/脲醛树脂多组分复合材料制备与表征

以钨粉为核芯材料,利用溶胶-凝胶法在其表面包覆二氧化硅壳层;通过硅烷化试剂(APTES)的修饰作用,在酸催化条件下,在钨/二氧化硅表面实施甲醛和尿素的缩聚反应,制备得到具有核-壳结构的钨/二氧化硅/脲醛树脂(W/SiO2/UF)多组分复合材料.通过扫描电子显微镜(SEM)、X-射线衍射(XRD)和傅立叶转变红外(FT-IR)等手段对复合材料的形态、结构和组成等进行了表征.复合材料的导电性测试结果表明,钨粉表面脲醛树脂层包覆后,其电导率由1.7×10-3S/m降低为1.2×10-8 S/m,即钨粉表面包覆层的包覆较为完整、致密,其导电性接近于绝缘材料.

Preparation and characterization of tungsten/silica/urea-formaldehyde resin multiful-component composite materials

The SiO2 layer coated on the tungsten powders(W/SiO2) by the sol-gel technique was firstly carried out.After modification of(3-aminopropyl)-triethoxysilane(APTES) onto the W/SiO2 particle surface,W/SiO2/UF multi-component composites with core-shell structures were fabricated via polycondensation between formaldehyde and urea under acidic condition.The morphologies,the structures and the composition of composite materials were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),and Fourier transform infrared spectrometer(FT-IR) techniques.The conductivity of the prepared composite materials significantly decreased from 1.7×10-3 S/m to 1.2×10-8 S/m,after coating of urea-formaldehyde resin layer on the surface of W/SiO2.It was showed that the prepared W/SiO2/UF multi-component composites are of the quite full and dense coating layer,and the conductivity is nearly close to the insulating materials.