Fenta Amanu Asmare, Ali Addisu Negash
Faculty of Mechanical and Industrial Engineering, Bahir Dar Institute of Technology, Bahir Dar University, P.O.Box26, Bahir Dar, Ethiopia.
Heliyon. 2024 Jan 11;10(2):e24424. doi: 10.1016/j.heliyon.2024.e24424. eCollection 2024 Jan 30.
The aim of this research is to develop high carbon-yielding biochar from pinewood, coffee husk, sugarcane bagasse, and maize cob and to characterize the biochar/HDPE composites for electromagnetic (EM) shielding application. During the biochar/HDPE composites fabrication, slow pyrolysis and compression molding manufacturing were used. The enhanced properties characterizations were conducted by using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), differential thermal analysis (DTA), Fourier transform spectrometry (FTIR), Brunauer-Emmet-Teller (BET) analysis, digital multi-meter, and proximity analysis. The results of biochar pyrolysis showed the maximum carbon yield of 74.6 %, 68.9 %, 68.4 %, and 40 % for pine wood, maize cob, sugarcane bagasse, and coffee husk respectively. The BET analysis showed the maximum specific surface area (734.5 m/g), pore volume (0.2364 cm/g), and pore radius (9.897 Å) from the pine wood biochar. The biochar loading analysis results showed that the 30 % and 40 % pine wood biochar significantly enhanced the electrical conductivity, thermal conductivity, thermal stability, crystallinity, and EM shielding effectiveness (SE) of the biochar/HDPE composites. In particular, the biochar/HDPE composite with 30 wt% pine wood biochar showed the highest thermal conductivity of 2.219 W/mK, and the 40 wt% pine wood biochar/HDPE composite achieved the highest electrical conductivity of 4.67 × 10 S/cm and EM SE of 44.03 dB at 2.1 GHz.
本研究的目的是利用松木、咖啡壳、甘蔗渣和玉米芯制备高碳产率的生物炭，并对生物炭/高密度聚乙烯（HDPE）复合材料进行表征，以用于电磁（EM）屏蔽应用。在制备生物炭/HDPE复合材料的过程中，采用了慢速热解和压缩成型工艺。通过热重分析（TGA）、扫描电子显微镜（SEM）、差示热分析（DTA）、傅里叶变换光谱仪（FTIR）、布鲁诺尔-埃米特-泰勒（BET）分析、数字万用表和邻近分析等方法对增强性能进行了表征。生物炭热解结果表明，松木、玉米芯、甘蔗渣和咖啡壳的最大碳产率分别为74.6%、68.9%、68.4%和40%。BET分析表明，松木生物炭的最大比表面积为734.5 m²/g、孔体积为0.2364 cm³/g、孔半径为9.897 Å。生物炭负载量分析结果表明，30%和40%的松木生物炭显著提高了生物炭/HDPE复合材料的电导率、热导率、热稳定性、结晶度和电磁屏蔽效能（SE）。特别是，含30 wt%松木生物炭的生物炭/HDPE复合材料的热导率最高，为2.219 W/mK，含40 wt%松木生物炭的生物炭/HDPE复合材料在2.1 GHz时的电导率最高，为4.67×10⁻⁴ S/cm，电磁屏蔽效能为44.03 dB。
