Setswalo K, Oladijo O P, Namoshe M, Akinlabi E T, Sanjay M R
Department of Mechanical, Industrial and Energy Engineering, Botswana International University of Science and Technology, Palapye, Botswana.
Department of Chemical, Materials and Metallurgical Engineering, Botswana International University of Science and Technology, Palapye, Botswana.
Int J Biol Macromol. 2022 Sep 30;217:398-406. doi: 10.1016/j.ijbiomac.2022.07.075. Epub 2022 Jul 14.
The desire of producing marketable green bio-composites displaying good functional properties has increased. Biodegradable composites are a subject of interest as they respond to ecological concerns. In this study, an eco-friendly alkali-laccase modification was used to improve the interfacial adhesion of mukwa wood fiber and polylactic acid (PLA) matrix. The untreated and treated mukwa-PLA composites were fabricated via extrusion and compression molding technique and investigated. The mukwa wood fibers and mukwa-PLA composites were characterized by chemical composition, crystallite size, Fourier transform infrared spectroscope (FTIR), mechanical properties, and scanning electron microscope (SEM) respectively. The cellulose content was found to increase, while the hemicellulose, lignin, and extractives reduced after the surface modifications. The alkali-laccase, laccase, and alkali modifications increased the tensile strength of the untreated/PLA composites by 12.3 %, 5.2 %, and 3.8 % respectively. The flexural strength of the composites reached a maximum of 95.1 MPa following the alkali-laccase treatment. The alkali-laccase treated composites showed increased impact strength of 53.9 % on the untreated/PLA composites. Good correlations between the crystallite size and the mechanical properties were reported, with the highest R-square (R) value of 1 found between the impact strength and crystallite size. The modifications strengthened the interaction between mukwa and PLA as more voids, fiber pull-outs, and debonding characteristics were observed on SEM microstructures of untreated/PLA.
生产具有良好功能特性的适销绿色生物复合材料的需求日益增加。可生物降解复合材料因其符合生态关注而成为研究热点。在本研究中，采用了一种环保的碱 - 漆酶改性方法来改善穆夸木纤维与聚乳酸（PLA）基体之间的界面粘附力。通过挤出和压缩成型技术制备并研究了未处理和处理后的穆夸木 - PLA复合材料。分别通过化学成分、微晶尺寸、傅里叶变换红外光谱仪（FTIR）、力学性能和扫描电子显微镜（SEM）对穆夸木纤维和穆夸木 - PLA复合材料进行了表征。发现表面改性后纤维素含量增加，而半纤维素、木质素和提取物含量降低。碱 - 漆酶、漆酶和碱改性分别使未处理/PLA复合材料的拉伸强度提高了12.3%、5.2%和3.8%。碱 - 漆酶处理后复合材料的弯曲强度最高达到95.1MPa。碱 - 漆酶处理的复合材料相对于未处理/PLA复合材料的冲击强度提高了53.9%。据报道，微晶尺寸与力学性能之间存在良好的相关性，冲击强度与微晶尺寸之间的决定系数（R）值最高为1。改性增强了穆夸木与PLA之间的相互作用，因为在未处理/PLA的SEM微观结构上观察到更多的空隙、纤维拔出和脱粘特征。
