Characterization of the Mechanical and Morphological Properties of Cow Dung Fiber-Reinforced Polymer Composites: A Comparative Study with Corn Stalk Fiber Composites and Sisal Fiber Composites

Natural fibers and their composites have attracted much attention due to the growing energy crisis and environmental awareness. In this work, a natural lignocellulosic fiber was extracted from cow dung waste and its potential use as reinforcing material in resin-based polymer composites was evaluated. For this purpose, cow dung fiber-reinforced composites (CDFC) were fabricated, and their mechanical and morphological properties were systematically investigated and compared with corn stalk fiber composites (CSFC) and sisal fiber composites (SFC). The results showed that the addition of cow dung fibers reduced the density of the polymer composites, increased the water absorption, and enhanced the impact strength and shear strength. The highest impact and shear strengths were obtained at 6 wt.% and 9 wt.% of fiber loading, respectively, which increased by 23.8% and 34.6% compared to the composite without the fibers. Further comparisons revealed that at the same fiber addition level, the CDFC exhibited better mechanical properties than the CSFC; notably, the CDFC-3 (adding 3 wt.% of fiber loading) had an impact strength closer to the SFC-3. Furthermore, an SEM analysis suggested that the cow dung fibers exhibited a rough and crinkly surface with more node structures, and presented good interfacial bonding with the composite matrix. This work revealed that cow dung fibers are a promising candidate as reinforcement for resin-based polymer composites, which promotes an alternative application for cow dung waste resources in the automotive components field.