Shah Atta Ur Rehman, Jalil Abdul, Sadiq Atiya, Alzaid Meshal, Naseem Muhammad Shoaib, Alanazi Rakan, Alanazi Sultan, Alanzy Abdullatyf Obaid, Alsohaimi Ibrahim Hotan, Malik Rizwan Ahmed
Department of Mechanical Engineering, COMSATS University Islamabad, Wah Campus, Wah Cantt 47040, Pakistan.
Department of Mechanical Engineering, HITEC University, Taxila 47050, Pakistan.
Polymers (Basel). 2023 Oct 9;15(19):4031. doi: 10.3390/polym15194031.
Given the rising consumption of plastic products, it is becoming imperative to prioritize the recycling of plastic items as a solution to reducing plastic waste and environmental pollution. In this context, this research focuses on assessing the impact of incorporating rice husk and wood flour into recycled high-density polyethylene (rec-HDPE) to analyze its mechanical properties, flammability, and thermal stability. The combined rec-HDPE content of wood flour and rice husk varied between 0% and 20%. The rec-HDPE content of maleic anhydride grafted polyethylene (MAPE) was fixed at 3%. Mechanical characteristics such as flexural, tensile, and impact strengths were assessed. Cone calorimetry (CC) tests, limited oxygen index (LOI) tests, and horizontal and vertical burning tests were performed to determine the flammability or fire retardancy of these composites. On the other hand, to characterize the thermal characteristics of these composites, thermogravimetric analysis (TGA) was used. To further characterize the fluctuation in these characteristics, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) studies were carried out. The mechanical characteristics were found to be increased in response to adding rice husk or wood flour. An 8% increase in tensile strength and a 20% increase in elastic modulus enhancement were recorded for a 20% rice husk-added composite. SEM revealed the reason for the variation in tensile properties, based on the extent of agglomeration and the extent of uniform distribution of fillers in rec-HDPE. Following these lines, the 20% rice husk-added composite also showed a maximum increase of around 6% in its flexural strength and a maximum increase of 50% in its flexural modulus. A decrease in impact strength was recorded for rice husk and wood flour-reinforced composites, compared with unreinforced rec-HDPE. Hybrid composites displayed a lack of mechanical strength due to changes in their nature. FTIR tests were performed for a much more elaborate analysis to confirm these results. Twenty percent of rice husk-added rec-HDPE displayed the best thermal properties that were tested, based on TGA and derivative thermogravimetric (DTG) analysis. This 20% composite also displayed the best fire-retardancy characteristics according to UL 94 tests, cone calorimetry tests, and limited oxygen index tests, due to the barrier created by the silica protective layer. These tests demonstrated that the incorporation of both fillers-rice husk and wood flour-effectively enhanced the thermal, mechanical, and fire-retardant attributes of recycled HDPE.
鉴于塑料制品的消费量不断上升，将塑料物品的回收作为减少塑料垃圾和环境污染的解决方案变得势在必行。在此背景下，本研究聚焦于评估将稻壳和木粉掺入再生高密度聚乙烯（rec-HDPE）中的影响，以分析其机械性能、可燃性和热稳定性。木粉和稻壳的 rec-HDPE 组合含量在 0%至 20%之间变化。马来酸酐接枝聚乙烯（MAPE）的 rec-HDPE 含量固定为 3%。评估了诸如弯曲强度、拉伸强度和冲击强度等机械特性。进行了锥形量热法（CC）测试、极限氧指数（LOI）测试以及水平和垂直燃烧测试，以确定这些复合材料的可燃性或阻燃性。另一方面，为了表征这些复合材料的热特性，使用了热重分析（TGA）。为了进一步表征这些特性的波动情况，进行了扫描电子显微镜（SEM）和红外光谱（FTIR）研究。发现添加稻壳或木粉后机械特性有所提高。对于添加 20%稻壳的复合材料，拉伸强度提高了 8%，弹性模量提高了 20%。SEM 揭示了拉伸性能变化的原因，这基于 rec-HDPE 中填料的团聚程度和均匀分布程度。按照这些情况，添加 20%稻壳的复合材料弯曲强度也最大提高了约 6%，弯曲模量最大提高了 50%。与未增强的 rec-HDPE 相比，稻壳和木粉增强的复合材料冲击强度有所降低。由于其性质的变化，混合复合材料显示出机械强度不足。进行了 FTIR 测试以进行更详尽的分析来证实这些结果。基于 TGA 和微商热重（DTG）分析，添加 20%稻壳的 rec-HDPE 显示出所测试的最佳热性能。根据 UL 94 测试、锥形量热法测试和极限氧指数测试，这种 20%的复合材料还显示出最佳的阻燃特性，这是由于二氧化硅保护层形成的屏障所致。这些测试表明，同时掺入稻壳和木粉这两种填料有效地增强了再生 HDPE 的热、机械和阻燃性能。
