Enhanced Mechanical, Thermal, and Electrical Properties of PLA via PTMEG Plasticization and MWCNT Reinforcement

ABSTRACT This study investigates the effects of polytetramethylene ether glycol (PTMEG) plasticizer and multi‐walled carbon nanotubes (MWCNTs) on the physical, mechanical, thermal, structural, and electrical properties of poly(lactic acid) (PLA)–based composites. PLA was first blended with varying PTMEG contents (10–20 wt%), followed by incorporation of surface‐modified MWCNTs (0.25–1 wt%). Miscibility evaluation using Flory–Huggins interaction parameters confirmed near‐miscible PLA/PTMEG behavior (χ < 0.5). Differential scanning calorimetry showed a significant reduction in glass transition temperature ( T g ) from 56°C in neat PLA to 24°C at 20 wt% PTMEG, accompanied by increased crystallinity. Tensile testing revealed striking ductility improvements, with elongation at break increasing up to 82‐fold, though strength and modulus decreased due to plasticization. Incorporation of MWCNTs improved modulus and tensile strength but reduced ductility; 0.75 wt% MWCNT yielded the optimal balance, with a 20‐fold increase in elongation compared to virgin PLA and a modulus 4.3× higher than plasticized PLA. XRD confirmed enhanced α‐phase crystallization, supported by FE‐SEM images showing uniform CNT dispersion with limited aggregation. Electrical testing revealed a ~10 6 ‐fold reduction in resistivity at 1 wt% MWCNT, indicating formation of conductive pathways. Overall, combined PTMEG and MWCNT addition significantly improved toughness, crystallinity, and electrical performance of PLA, providing a promising route for advanced biodegradable composite applications.