Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Preparation method of PLA-PTMEG blends and their nanocomposites, followed by their mechanical/thermal properties.

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 ~106-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.