Tahir Irfan, Rapinac John, Abutunis Abdulaziz, Menta Venkata Gireesh
Mechanical & Industrial Engineering, University of Minnesota Duluth, Duluth, MN 55812, USA.
Polymers (Basel). 2022 Feb 12;14(4):706. doi: 10.3390/polym14040706.
The utilization of eco-friendly materials, such as lignin, for higher value product applications became increasingly important as environmental concerns due to global warming increased. Melt blending is one of the easy ways to increase the usage of lignin in commercial applications. However, the degradation of the final product performance and increase in the production time and costs are of major concern. In the current work, the effects of blending lignin, extracted from tobacco plants, with polypropylene (PP) on the injection molding parameters, physical, thermal and mechanical properties are investigated. Blends of lignin (5, 15 and 30% by wt.) with PP were prepared using a Filabot single screw extruder. Results show that tensile strength decreases by 3.2%, 9.9% and 5.4% at 5 wt. %, 15 wt. %, and 30 wt. % of lignin addition, respectively. The tensile stiffness was almost unaffected by the addition of up to 15% lignin, but a 23% increase was observed at 30 wt. % loading. When compared to lignin processed via expensive processes, such as acetylation, tobacco lignin showed superior performance. The DSC results show unaffected crystallization and melting temperatures but a decrease in enthalpies and percentage of crystallinity. The SEM and optical micrographs of the coupon cross-sections show that the extrusion process has achieved a uniform distribution of lignin particles in the PP. Thermogravimetric analysis results show that tobacco lignin accelerates the onset decomposition temperature but does not influence the decomposition peak temperature. The increase in lignin content did not have a significant influence on the injection molding parameters, implying no additional processing costs for adding lignin to the PP. Overall, the performance of the tobacco lignin is comparable, if not better, than that of processed lignin reported in the literature.
随着全球变暖引发的环境问题日益严重，利用木质素等环保材料生产高价值产品变得愈发重要。熔融共混是增加木质素在商业应用中用量的简便方法之一。然而，最终产品性能的下降以及生产时间和成本的增加是主要问题。在当前工作中，研究了将从烟草植物中提取的木质素与聚丙烯（PP）共混对注塑成型参数、物理、热学和力学性能的影响。使用Filabot单螺杆挤出机制备了木质素（质量分数分别为5%、15%和30%）与PP的共混物。结果表明，添加5 wt.%、15 wt.%和30 wt.%木质素时，拉伸强度分别降低了3.2%、9.9%和5.4%。添加量高达15%的木质素时，拉伸刚度几乎不受影响，但在30 wt.%的添加量下观察到拉伸刚度增加了23%。与通过乙酰化等昂贵工艺处理的木质素相比，烟草木质素表现出更优异的性能。差示扫描量热法（DSC）结果表明，结晶温度和熔融温度未受影响，但焓值和结晶度百分比有所下降。试样横截面的扫描电子显微镜（SEM）和光学显微镜照片表明，挤出过程实现了木质素颗粒在PP中的均匀分布。热重分析结果表明，烟草木质素提高了起始分解温度，但不影响分解峰值温度。木质素含量的增加对注塑成型参数没有显著影响，这意味着向PP中添加木质素不会增加额外的加工成本。总体而言，烟草木质素的性能即使不比文献中报道的加工木质素更好，也与之相当。
