Tuning multifunctional behavior of PLA/POE‐g‐GMA/MWCNT nanocomposites: Mechanical, rheological, thermal, thermomechanical, and electromagnetic properties

Abstract

Nanocomposites of polylactic acid (PLA) and poly(ethylene‐octene) grafted with glycidyl methacrylate (POE‐g‐GMA) were prepared using multi‐walled carbon nanotubes (MWCNT) as conductive nanofillers. The PLA/POE‐g‐GMA/MWCNT nanocomposites were processed through extrusion and injection molding for rheological, mechanical, electromagnetic, thermal, thermomechanical, and morphological characterization. The carbon nanotubes were dispersed in the PLA/POE‐g‐GMA chain, as seen by Raman spectroscopy. With higher MWCNT content, the complex viscosity (η*) and storage modulus (G') significantly increased in the nanocomposites, suggesting percolation formation. The nanocomposites melt flow index (MFI) results indicated lower fluidity, confirming the trend in η*. Electrical conductivity was optimal for PLA/POE‐g‐GMA/MWCNT (5 phr), reaching a value of 2.21°×°10−6 S/cm and providing electromagnetic shielding of 8 dB across the entire Ku band (12.2–18 GHz). The impact strength of the nanocomposites was higher than that of pure PLA and the PLA/POE‐g‐GMA blend, while the heat deflection temperature (HDT) remained stable at around 56°C. Increased MWCNT content in the nanocomposites promoted recovery of the elastic modulus, tensile strength, and Shore D hardness compared to PLA/POE‐g‐GMA blend. Overall, the results indicate that the PLA/POE‐g‐GMA/MWCNT (5 phr) nanocomposite has potential antistatic applications.