The high cost of mineral-based fillers and their processing difficulties have necessitated the search for alternative and cheaper filler materials, usually agro-waste materials such as coconut shells. The coconut shells were carbonized, pulverized, and sieved into four particles sizes, namely; 63 μm, 150 μm, 300 μm, and 425 μm. The carbonized coconut shell particles of each particle size were used as fillers in the preparation of polypropylene-filled composites at filler loadings of 0, 10, 20, 30, and 40 wt. %. The control was the neat polypropylene of 0% filler addition. The polypropylene/carbonized coconut shell particles composites were prepared via melt blending of polypropylene and the filler in an injection molding machine to obtain composite sheets. The influence of filler loading on the mechanical properties was evaluated. The addition of fillers was found to improve the yield strength, tensile strength, tensile modulus, flexural strength, flexural modulus, and hardness of polypropylene as these mechanical properties increased with increase in filler loading. The elongation at break and modulus of resilience of the prepared polypropylene/carbonized coconut shell particles composites were, however, observed to decline with an increase in the filler loading. Compared with the neat polypropylene, the filler showed enhanced mechanical properties in the prepared composites. SEM revealed good filler–matrix interaction because of good interfacial adhesion. The incorporation of more filler resulted in the formation of more spherulite-producing nuclei, reduction of pore sizes, and enhanced particle size distribution with improved mechanical properties. Experimental data modeling showed the addition of more than 48% carbonized coconut shell particles to polypropylene would compromise property enhancement.

中文翻译：

---

填料用量对炭化椰壳颗粒增强聚丙烯复合材料力学和形态性能的影响

矿物填料的高成本及其加工困难迫使人们必须寻找替代且更便宜的填料，通常是椰子壳等农业废料。将椰壳炭化、粉碎、筛分成四种粒径，即；63 μm、150 μm、300 μm 和 425 μm。在聚丙烯填充复合材料的制备中，每种粒径的碳化椰子壳颗粒用作填料，填料量为 0、10、20、30 和 40 重量％。%。对照是添加了 0% 填料的纯聚丙烯。聚丙烯/碳化椰壳颗粒复合材料是通过聚丙烯和填料在注塑机中熔融共混得到复合片材而制备的。评估了填料负载对机械性能的影响。发现添加填料可以提高聚丙烯的屈服强度、拉伸强度、拉伸模量、弯曲强度、弯曲模量和硬度，因为这些机械性能随着填料用量的增加而增加。然而，观察到制备的聚丙烯/碳化椰子壳颗粒复合材料的断裂伸长率和回弹性模量随着填料负载的增加而下降。与纯聚丙烯相比，填料在制备的复合材料中表现出增强的机械性能。由于良好的界面粘附性，SEM 显示出良好的填料-基质相互作用。加入更多的填料导致形成更多的球晶核、孔径减小、粒度分布增强、机械性能提高。