Xia Changlei, Zhang Shifeng, Ren Han, Shi Sheldon Q, Zhang Hualiang, Cai Liping, Li Jianzhang
Department of Mechanical and Energy Engineering, University of North Texas, Denton, TX 76203, USA.
MOE Key Laboratory of Wooden Material Science and Application, Beijing Key Laboratory of Wood Science and Engineering, Beijing Forestry University, Beijing 100083, China.
Materials (Basel). 2015 Dec 25;9(1):10. doi: 10.3390/ma9010010.
Kenaf fiber-polyester composites incorporated with powdered activated carbon (PAC) were prepared using the vacuum-assisted resin transfer molding (VARTM) process. The product demonstrates the electromagnetic interference (EMI) shielding function. The kenaf fibers were retted in a pressured reactor to remove the lignin and extractives in the fiber. The PAC was loaded into the freshly retted fibers in water. The PAC loading effectiveness was determined using the Brunauer-Emmett-Teller (BET) specific surface area analysis. A higher BET value was obtained with a higher PAC loading. The transmission energies of the composites were measured by exposing the samples to the irradiation of electromagnetic waves with a variable frequency from 8 GHz to 12 GHz. As the PAC content increased from 0% to 10.0%, 20.5% and 28.9%, the EMI shielding effectiveness increased from 41.4% to 76.0%, 87.9% and 93.0%, respectively. Additionally, the EMI absorption increased from 21.2% to 31.7%, 44.7% and 64.0%, respectively. The ratio of EMI absorption/shielding of the composite at 28.9% of PAC loading was increased significantly by 37.1% as compared with the control sample. It was indicated that the incorporation of PAC into the composites was very effective for absorbing electromagnetic waves, which resulted in a decrease in secondary electromagnetic pollution.
采用真空辅助树脂传递模塑（VARTM）工艺制备了掺入粉末活性炭（PAC）的红麻纤维-聚酯复合材料。该产品具有电磁干扰（EMI）屏蔽功能。将红麻纤维在压力反应器中进行脱胶处理，以去除纤维中的木质素和提取物。将PAC加入到刚脱胶处理后的水中的纤维中。使用布鲁诺尔-埃米特-泰勒（BET）比表面积分析来确定PAC的负载效果。PAC负载量越高，获得的BET值越高。通过将样品暴露在频率从8 GHz到12 GHz变化的电磁波辐射下，测量复合材料的传输能量。随着PAC含量从0%增加到10.0%、20.5%和28.9%，EMI屏蔽效能分别从41.4%增加到76.0%、87.9%和93.0%。此外，EMI吸收分别从21.2%增加到31.7%、44.7%和64.0%。与对照样品相比，PAC负载量为28.9%时复合材料的EMI吸收/屏蔽比显著提高了37.1%。结果表明，在复合材料中掺入PAC对吸收电磁波非常有效，这导致了二次电磁污染的减少。
