双性磁屏蔽复合材料的制备与效能

Preparation and efficiency of dual magnetic shielding composites

将Fe(OH)3与可膨胀石墨GIC共膨化制备了Fe3O4-GIC微集料,并将不同含量微集料与苯并恶嗪单体(BA-a)复合,固化后得到Fe3O4-GIC/PBA-a复合材料。采用傅里叶红外光谱、X射线衍射仪、示差扫描量热分析、扫描电镜、电导率、磁感应强度及电磁屏蔽效能测试研究了制备条件对微集料结构和性能的影响以及微集料含量不同的Fe3O4-GIC/PBA-a复合材料的固化及固化物的各项性能。结果表明,微集料的最佳制备条件如下:膨化温度1000℃,Fe(OH)3与GIC质量比1∶1。微集料可催化BA-a的固化,并与其发生交联反应。微集料与BA-a具有较好的相容性,随着微集料含量增多,复合材料的电导率以及磁感应强度均随之增大。在低频下,复合材料具有较高的磁屏蔽效能,微集料加入质量分数为2.5%时复合材料的电磁屏蔽效能最高达到22.3 dB。同时,微集料的加入可显著提高复合材料的热稳定性。

The Fe3O4-GIC micro-aggregates were prepared by co-expansion of Fe(OH)3 and expandable graphite GIC,and different content of micro-aggregates were combined with benzoxazine monomer(BA-a)to obtain Fe3O4-GIC/PBA-a composites.The Fourier infrared spectroscopy,X-ray diffractometer,differential scanning calorimetry,scanning electron microscope and tests of electrical conductivity,magnetic induction intensity and electromagnetic shielding effectiveness were used to study the influence of preparation conditions on the structure and performance of micro-aggregates,curing of GIC/PBA-a composites with different content of micro-aggregates and the properties of the cured products.The results showed that the optimal preparation conditions of micro-aggregates were as follows:expanding temperature 1000℃,and the mass ratio of Fe(OH)3 to GIC 1∶1.The micro-aggregate could catalyze the curing of BA-a and undergo crosslinking reaction with it.The micro-aggregate had good compatibility with BA-a.With the content of the micro-aggregate increasing,the electrical conductivity and magnetic induction of the composite material were increased.At low frequencies,the composites had high magnetic shielding effectiveness.When the mass fraction of micro-aggregate was 2.5%,the electromagnetic shielding effectiveness of composites could reach 22.3 d B.At the same time,the addition of micro-aggregates could significantly improve the thermal stability of the composites.