Evaluating the acoustic and low-velocity impact behavior of sustainable polylactic acid (PLA)/poly(butylene adipate-co-terephthalate) (PBAT)/graphene nanoplatelet three-dimensional (GNP 3D) printed composites

Polymer-infused porous substances are lightweight porous materials, utilized in both internal and external elements, panels, electronic control units, and automotive suspension bushing components, thus paving the way for the rise of smarter, more efficient, and eco-friendly production techniques. The polylactic acid (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) represents a biodegradable polymer blend characterized by a bio-based composition, positioning it as a viable alternative to traditional petroleum-derived polymers. The inclusion of PBAT enhances the tear resistance of PLA while simultaneously mitigating its rigidity; therefore, nano material is incorporated as a filler within the composite blend to augment its properties. In this study, 35 wt% and 39 wt% of PBAT and 1 wt% and 5 wt% of graphene nanoplatelets (GNPs) are blended with PLA, and utilizing a twin-screw extruder, two different composite filaments are generated. Subsequently, six distinct composites are printed from the composite filaments employing the fused deposition modeling three-dimensional (3D) printing method by varying the infill densities (35%, 70%, and 100%). Investigations into the sound absorption characteristics and low-velocity impact performance of 3D printed composites are undertaken. Acoustic analysis of the printed composites is performed utilizing an acoustic testing apparatus, and the sound absorption coefficient (SAC) is computed employing MATLAB software. The composite with 35% infill density and 1 wt% GNP registered the highest values in SAC at low- and mid-frequency ranges. Whereas, the composite with 100% infill density and 1 wt% GNP registered the maximum SAC at the high-frequency range. In the low-velocity impact assessments, the composite with 1 wt% GNP markedly enhances the impact resistance, reflecting better energy absorption, stress transfer, and dissipation.