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首先利用原位化学氧化聚合法将聚苯胺包覆在粉煤灰漂珠表面(FAFB/PAn),再利用低温溶胶凝胶-水热法制备BaTiO_3包覆FAFB/PAn的复合材料(FAFB/PAn/BaTiO_3),形成内核为空心漂珠、外壳依次为导电层、绝缘层的核/壳结构.采用FTIR、XRD、SEM、数字式四探针以及LCR介电谱仪对FAFB/PAn/BaTiO_3复合材料的结构与性能进行分析;以FAFB/PAn/BaTiO_3为分散相制备的电流变液,对其悬浮性及外加电场下的剪切应力进行测试.FTIR和XRD结果证明了利用本文的实验方法可成功将PAn和BaTiO_3引入到FAFB表面.电导率测试结果表明,复合材料电导率为7.8×10~(-4)S·cm~(-1),相对BaTiO_3提高了近2个数量级.在1~2000 k Hz交变电场频率测试范围内,FAFB/PAn/BaTiO_3具有相对较好的介电性能:当f=1 k Hz时εr最大为598,随电场频率的增加介电常数逐渐减小,对应的介电损耗tanδ最大为1.14,且随电场频率的增加介电损耗逐渐减小,当f=200 k Hz时tanδ=0.75,后趋于平稳.比较了7天的悬浮稳定性发现,FAFB/PAn稳定性最好,悬浮率可达88%,而包覆BaTiO_3后与纯BaTiO_3相当,仅为60%.在电场作用下FAFB/PAn/BaTiO_3表现出较明显的电流变性能,即当E=4.0 k V/mm时,剪切应力达631 Pa,且具有较好的抗击穿能力.
First, polyaniline was coated on the surface of fly ash floating beads (FAFB / PAn) by in-situ chemical polymerization and FAFB / PAn composite coated with BaTiO 3 by hydrothermal method / BaTiO_3), the core was hollow floating beads, the shell followed by the core / shell structure of the conductive layer and the insulation layer.The FAFB / PAn / BaTiO_3 composite was characterized by FTIR, XRD, SEM, digital four-probe and LCR dielectric spectrometer The structure and properties of the materials were analyzed, and the rheological fluid prepared from FAFB / PAn / BaTiO_3 dispersed phase was used to test the shear stress under suspension and external electric field.FTIR and XRD results show that the experimental method PAn and BaTiO_3 were successfully introduced into the surface of FAFB.The results of conductivity measurement showed that the conductivity of the composite was 7.8 × 10 -4 S · cm -1 and increased by nearly two orders of magnitude compared with that of BaTiO 3, FAFB / PAn / BaTiO_3 has relatively good dielectric properties in the frequency range of 2000 k Hz alternating electric field: the maximum εr is 598 at f = 1 k Hz, and the dielectric constant decreases with increasing electric field frequency The dielectric loss tanδ is 1.14, and the dielectric loss decreases with the increase of the electric field frequency. When f = 20 When tanδ = 0.75 at 0 k Hz, it tends to be stable. After 7 days of suspension stability analysis, FAFB / PAn showed the best stability with a suspension rate of 88%. BaTiO_3 coated BaTiO_3 was equivalent to pure BaTiO_3 60%. FAFB / PAn / BaTiO_3 exhibits obvious electrorheological property under the action of electric field, that is, shear stress reaches 631 Pa at E = 4.0 kV / mm, and has better anti-breakdown ability.