Effect of graphite, zinc borate and Prosopis juliflora fiber particulates on mechanical and thermal properties of Sida acuta natural fiber reinforced composites

The mechanical, water absorption, and thermal properties of Sida acuta fiber reinforced composites added with fillers such as graphite, zinc borate, and Prosopis juliflora (PJ) fiber particulates were investigated. Tensile strength of Sida acuta fiber reinforced composites attained a maximum value of 34.48MPa and 39.59MPa with addition of 7 wt. % graphite and 10 wt. % PJ fiber particulates. Flexural and impact strength also attained their maximum value at 7 wt. % graphite and 10 wt. % Prosopis particulate addition. Graphite added specimens exhibited better resistance against water absorption wherein zinc borate offered the least resistance. Fourier transform infrared spectroscopy (FTIR) analysis confirmed the existence of functional groups that govern good compatibility and dispersion of filler particles within the polymer matrix. X-ray diffraction (XRD) plots revealed a substantial increase in the crystallinity index with the addition of graphite and PJ particulates. The addition of filler particles increases the crystallite size of composites. Composite with zinc borate and graphite showed superior flame-retardant characteristics through the formation of char and subsequent suppression of flame propagation. The morphological analysis of graphite and PF fibers added specimens revealed existence of dense microstructure with less voids and less fiber pullout and debonding failures.