Synergistic effect of fiber surface treatment and nanoclays on the damping behaviors of polyester composites reinforced with palmyra fruit fibers

Fibers extracted from the fruits of plants are less investigated for engineering applications as composites along with the engineering polymers. This study holistically developed less explored palmyra fruit fiber/polyester composites with or without montmorillonite nanoclays inclusions. Fibers extracted from the Palmyra fruit through special process were either untreated or chemically surface treated to improve interfacial bonding via mechanical anchoring matrix into fiber surfaces for mechanical strength. Fiber composites were manufactured through compression molding route, and the nanoclays are dispersed into the matrix before being compressed. The effects of various surface treatments on the chemistry and morphology of fibers were studied using scanning electron microscopy and Fourier transform infrared spectroscopy. The effect of fiber surface treatment and nanoclay incorporation on free vibrational behavior concerning the natural frequency and damping factor was also examined. Free vibration tests reveal that fiber surface treatment substantially impacts the natural frequency and damping factor of palmyra fruit fiber-reinforced composites (PFFCs). Specifically, NaOH-treated PFFCs have the maximum flexural strength, corresponding to the highest natural frequency. In addition, introducing nanoclays increases the flexural modulus beyond that of original PFFCs. After fiber surface treatments and the addition of nanoclays, modal analysis revealed the increase in composite stiffness through the changes noted in the composite damping results.