Effects of carbon-based nanoparticles on the properties of poly(lactic acid) hybrid composites containing basalt fibers and carbon-based nanoparticles processed by injection molding

In this study, we developed composites with a poly(lactic acid) matrix and reinforced with basalt fiber, carbon-based nanoparticles (carbon nanotube [CNT] and expanded graphene [GNP]), and both basalt fiber and nanoparticles (hybrid composites). The composites were produced by extrusion, and then tensile specimens were injection molded from the composites. The hybrid composites exhibited enhanced mechanical properties. The reinforcing materials increased crystallinity; this was more pronounced for hybrid composites. We experienced significant increase in the glass transition temperature, which proves the better interaction between the reinforcing and the matrix phases. Dynamic mechanical thermal analysis showed that the nanoparticles increased the storage modulus both alone and in combination with basalt fibers. Furthermore, the basalt fiber-reinforced composites and hybrids exhibited significant modulus above the glass transition temperature. Based on scanning electron microscopy images of the fracture surfaces, we concluded that adding basalt fibers during compounding resulted in better dispersion of the nanoparticles.Highlights Poly(lactic acid) (PLA) reinforced with basalt fiber has good strength properties. Graphene hybrid exhibits notable tensile modulus improvement in hybrids. Graphene and carbon nanotubes are crystalline nucleating agents for PLA. Enhanced nanoparticle distribution was discovered for hybrid composites. The glass transition temperature of PLA increases with reinforcement. In the hybrid nanocomposites containing basalt fibre and carbon nanotubes, the microfibres hamper the mobility of the nanotubes and molecules, and the molecule can be entangled through the nanotubes. As a result, load transfer to the reinforcing materials is more efficient, which is reflected in the enhanced mechanical properties. image