Ecological PLA/PBAT-g-GMA Nanocomposites Reinforced with Carbon Nanotubes for Electrostatic Charge Control: Evolution of Morphology, Electrical Conductivity and Mechanical Properties

Ecological and flexible polymeric nanocomposites are essential for sustainable development, considering their technological potential for the production of new materials with enhanced and multifunctional properties. At the same time, they help mitigate environmental impacts, thereby promoting innovation in packaging, electronics, and other applications, as well as assisting in the transition to a greener and more circular economy. In this study, poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) grafted with glycidyl methacrylate (PBAT-g-GMA) nanocomposites were processed by extrusion and injection molded, using multi-walled carbon nanotubes (MWCNT) as conductive fillers. The tested MWCNT contents were 0.5, 1.0, 3.0, and 5 parts per hundred resin (phr) in the PLA/PBAT-g-GMA (70/30% by weight) system, aiming to evaluate impact strength, tensile strength, Shore D hardness, electrical conductivity, and morphological evolution by scanning electron microscopy (SEM). The use of 30% PBAT-g-GMA in the PLA matrix significantly increased impact strength by 556%, suggesting an improvement in the toughening process. Pure PLA and the PLA/PBAT-g-GMA blend exhibited typical insulating behavior, with electrical conductivity around 3.1 x 10⁻¹¹ S/cm. The incorporation of MWCNT into PLA/PBAT-g-GMA markedly enhanced the impact strength of the nanocomposites, especially at 5 phr, with a gain of 1085% compared to pure PLA. Furthermore, a transition to a semiconducting material occurred in the PLA/PBAT-g-GMA/MWCNT (5 phr) nanocomposite, with an electrical conductivity of 4.31 x 10⁻⁶ S/cm. In contrast, no improvements were observed in Shore D hardness and the elastic modulus of the nanocomposites. This behavior was explained by the preferential migration of carbon nanotubes to PBAT-g-GMA, promoting greater stability in the morphology and refinement of the dispersed phase in the PLA matrix, justifying the significant gain in impact strength. The results indicate potential as a flexible and conductive nanocomposite for antistatic applications.