苎麻骨基电磁屏蔽材料的制备与表征

Preparation and characterization of bone-based electromagnetic shielding materials for ramie

【目的】制备具有金属特征的电磁屏蔽木质功能材料,可拓展苎麻骨的高值利用空间。【方法】以苎麻骨粉末为基材,以纳米氧化铜和环氧树脂为增强因子,以活性炭为纳米氧化铜原位还原诱发剂,采用温压成形工艺对均匀混合物实施双向压制成形,制备苎麻骨基复合材料;用X射线衍射仪、体式显微镜和同步扫描电镜分析其金属化特征与微观结构,用立式法兰同轴电磁屏蔽效能测试装置对比分析苎麻骨基复合材料与苎麻骨粉末基材的温压试件的电磁屏蔽效能。【结果】苎麻骨基复合材料的XRD图谱在2θ=43.22°和50.36°处(类似于金属Cu面心立方结构{111}以及{200}晶面)出现明显的衍射峰,其体式显微结构可见均匀紫铜色物质(单质铜);其SEM断口形貌呈韧性断裂特征,其电导率峰值达到9.56×10^(-6) S/m,其电磁屏蔽效能突破70 dB。【结论】纳米氧化铜在苎麻骨基复合材料温压成形过程中得以充分原位还原,使苎麻骨基复合材料实现金属化而赋予其优良的电磁屏蔽效能,超过工业电磁屏蔽应用标准水平(30~60 dB),达到了军工用标准(60~120 dB),展现出纳米增强金属化木质复合材料的广阔应用前景。

【Objective】The preparation of electromagnetic shielding wood functional materials with metal characteristics can expand the high value utilization space of ramie bone.【Method】Using ramie bone powder as substrate,nano-copper oxide and epoxy resin powder as reinforcing factor,activated carbon as in-situ reduction inducer of nano-copper oxide,the uniform mixture was bi-directional formed by warm compacting process to prepare ramie bone-based composites.By using X ray diffractometer,stereomicroscope and synchronous scanning electron microscope,the metallization characteristics and microstructure were analyzed,and the electromagnetic shielding effectiveness of ramie bone-based composite and ramie bone powder substrate was compared and analyzed by vertical flange coaxial electromagnetic shielding effectiveness test device.【Result】The XRD patterns of ramie bone-based composites showed obvious diffraction peaks at 2θ=43.22°and 50.36°(similar to the metal Cu face-centered cubic structure{111}and{200}crystal plane).Its bulk microstructure can be seen uniform copper-colored material(simple copper).The SEM fracture morphology is ductile fracture.The peak electrical conductivity reached 9.56×10^(-6)S/m.The electromagnetic shielding effectiveness exceeded 70 dB.【Conclusion】Nano-copper oxide can be fully reduced in situ in the process of warm compaction of ramie bone-based composites,so that ramie bone-based composites can be metallized and give them excellent electromagnetic shielding efficiency.It exceeds the standard level of industrial electromagnetic shielding(30-60 dB)and meets the standard of military industry(60-120 dB).It shows a broad application prospect of nano-reinforced metallized wood composites.