Synergistic effect of alkali and silane treatment on mechanical, flammability, and thermal degradation of hemp fiber/epoxy composite

Abstract

AbstractCurrently, natural fiber composites are used in many applications (industrial, automotive, and construction) where fire resistance is a critical factor. The main objective of this research work is to investigate the thermal degradation and fire performance of raw and treated fiber composites developed using hand layup with different fiber loadings of 5, 10, 15, and 20 wt%. Alkali treatment (5%, wt/vol) and silane treatment (5%, wt/vol) were used to improve the thermal stability and compatibility of hemp fiber with polymer matrix. The developed composites were characterized for thermal (thermogravimetric analysis), chemical (Fourier transform spectroscopy), morphological (scanning electron microscopy and X‐ray diffraction), and mechanical behavior. Further, the flammability behavior of the developed composites was investigated using vertical cum horizontal flammability test apparatus and limiting oxygen index (LOI) tester. The results of mechanical characterization reveal that alkali treated fiber composites (20% loading) have the highest tensile strength (24.4 MPa) and flexural strength (46.1 MPa). Composite reinforced with silane‐treated fibers have shown excellent flame retardancy with the lowest horizontal burning rate (16.11 mm/min) and higher LOI (23.5%). Scanning electron microscopy confirms the better fiber‐matrix compatibility of silane‐treated fiber with epoxy.