电磁屏蔽碳毡叠层型胶合板的性能研究

【目的】基于叠层型电磁屏蔽结构模型,将电磁屏蔽碳毡与杨木单板叠层复合制备抗电磁干扰的电磁屏蔽胶合板。研究了电磁屏蔽碳毡的碳纤维填充量对该胶合板的电磁屏蔽性能与胶合性能的影响, 进而探究双层叠层型电磁屏蔽结构模型的可行性。【方法】采用同轴测试方法和抗剪实验分别测试了电磁屏蔽碳毡叠层型胶合板的电磁屏蔽性能和胶合性能,通过微观结构表征分析了碳纤维在电磁屏蔽碳毡内的网络搭接状况。【结果】当碳纤维填充量达到25 g/m²时,电磁屏蔽碳毡内开始形成“三维电磁屏蔽网络”。电磁屏蔽碳毡叠层型胶合板的屏蔽效能随着碳纤维填充量的增加而逐渐增大; 当碳纤维填充量为120 g/m²时, 双层电磁屏蔽碳毡叠层型胶合板的屏蔽效能为52.61～68.37 dB(100 kHz～1.5 GHz),达到中等屏蔽效果(60～90 dB)。在碳纤维填充量相同的条件下,双层电磁屏蔽碳毡叠层型胶合板的屏蔽性能优于单层电磁屏蔽碳毡叠层型胶合板; 前者的电磁屏蔽优势随着碳纤维填充量与测试频率的增加而逐渐减小。此外,双层电磁屏蔽碳毡叠层型胶合板的胶合强度大于单层电磁屏蔽碳毡叠层型胶合板的胶合强度。电磁屏蔽碳毡叠层型胶合板的胶合强度大于GB/T 9846.3—2004 Ⅰ类胶合板标准所规定的杨木单板最低胶合强度值(0.7 MPa)。【结论】电磁屏蔽碳毡的双层叠层复合有效提高了电磁屏蔽碳毡叠层型胶合板的电磁屏蔽性能和胶合性能,证实了双层叠层型电磁屏蔽结构模型的可行性。

Research on properties of plywood laminated with electromagnetic shielding carbon felts

【Objective】Based on the structural model of laminated electromagnetic shielding, electromagnetic shielding carbon felts were laminated with poplar veneers to manufacture electromagnetic shielding plywood to efficiently minimize the hazard caused by electromagnetic interference. Effects of the carbon fiber filler content of the electromagnetic shielding carbon felt on electromagnetic shielding performance and bonding performance of the manufactured plywood were investigated. In addition, the feasibility of the double-layer laminated shielding structure was analyzed.【Method】Shielding effectiveness(SE)and shear strength of the plywood laminated with electromagnetic shielding carbon felts were investigated by using a coaxial test and shear test, respectively. Furthermore, carbon fiber distributions in the plane and cross-sections of the electromagnetic shielding carbon felt were observed by using a metallurgic microscope.【Result】It was observed that a “three-dimensional electromagnetic shielding network” was starting to form in the electromagnetic shielding carbon felt as the carbon fiber filler content increased to 25 g/m². The results revealed that the SE of plywood laminated with electromagnetic shielding carbon felts increased with increasing carbon fiber filler content. It was found that SE of the plywood, which was laminated with a double-layer electromagnetic shielding carbon felt(120 g/m²), ranged from 52.61 to 68.37 dB(100 kHz-1.5 GHz), and had a medium shielding performance(60-90 dB). Additionally, plywood laminated with the double-layer electromagnetic shielding carbon felts exhibited higher SE than the plywood laminated with the single-layer electromagnetic shielding carbon felt at the same total carbon fiber filler content. However, the SE advantage of the former was reduced with the increase in carbon fiber filler content and testing frequency. The results also revealed that the plywood laminated with double-layer electromagnetic shielding carbon felt exhibited greater shear strength than plywood laminated with single-layer electromagnetic shielding carbon felt. The shear strength of plywood laminated with electromagnetic shielding carbon felts exceeded the minimum value of 0.7 MPa, which is required by the Chinese plywood standard of GB/T 9846.3—2004. 【Conclusion】 Electromagnetic shielding performance and bonding performance of the manufactured plywood are effectively improved after the lamination of electromagnetic shielding carbon felts. Furthermore,the laminated structure model was proved to be feasible in this study.