Fiber treatment impact on toughness and interfacial bonding in epoxidized soya bean oil compatibilized PLA/PBAT bamboo fiber composites

Biodegradable plastics such as Poly(lactic acid) (PLA) and polybutylene adipate terephthalate (PBAT) are commonly used in composite fabrication and applications. However, their inherent properties limit their use. In this study, Epoxidised soyabean oil (ESO) compatibilized PLA/PBAT was filled with modified bamboo fiber (BF). The BF was modified in a two-stage environmentally friendly process involving steam treatment followed by a new approach to hydrophobic natural fiber modification with naturally occurring fatty acid (myristic acid) (MA). Then, the ESO/PLA/PBAT/BF composite was fabricated, and the influence of the new fiber modification method on the toughness and interface bonding of the composite was studied. The composite was characterized using mechanical analysis, scanning electron microscopy (SEM), thermogravimetry analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), water contact angle measurement, and statistical methods. The melting behavior was also studied using Vicat softening and heat deflection temperatures. The ESO compatibilisation improved the compatibility of the PLA/PBAT blend, resulting in a continuous PLA/PBAT phase, as evidenced by the interface modulus, glass transition temperature, and fractured surface. The modification of BF enhanced its dispersion in the matrix and improved interfacial adhesion. Elongation at break and impact toughness were improved by more than double compared to neat PLA. Adding PBAT and modified BF to PLA resulted in a thermally stable composite. The statistical analysis results suggested that BF modification and BF loading significantly influenced the composite strength and toughness (P ≤ 0.05). The tough and flexible composite material can used in flexible/lightweight and impact-resistant applications, consumer goods, and heat shields.