In this study, polylactic acid (PLA) nanocomposites reinforced with halloysite nanotubes (HNTs) were fabricated via melt extrusion followed by compression molding. Surface modification of HNTs was conducted using polyethyleneimine (PEI) and PN40 to improve interfacial interaction and dispersion of HNTs within the PLA matrix. The effects of HNT surface modification on the structural, thermal, and mechanical properties of the PLA matrix was systematically evaluated. Zeta potential and Fourier‐transform infrared (FTIR) analyses confirmed the successful functionalization of HNTs, with PEI treatment exhibiting a more pronounced surface charge modification compared to virgin and PN40‐modified HNTs. SEM and atomic force microscopy (AFM) images demonstrated that the dispersion and interfacial adhesion of HNTs in the PLA matrix were significantly enhanced in the nanocomposites containing PEI–modified HNTs. Thermal analyses revealed that the incorporation of HNTs led to a slight increase in the glass transition and melting temperatures, as well as enhanced thermal degradation resistance. Moreover, nanocomposites containing 3 wt% PEI–modified HNTs exhibited the highest thermal stability, with the temperature at 5 and 10 wt% weight loss, and the temperature of maximum degradation rate observed in the derivative thermogravimetric (DTG) curve measured at 349.9, 359.5, and 396.9°C, respectively. These values represent increases of 9.8, 10.5, and 14.4°C compared to pure PLA. Tensile testing demonstrated that the nanocomposites containing 1–3 wt% PEI–modified HNTs achieved the highest tensile strength, showing an increase of over 7% relative to pure PLA. Overall, the results demonstrate that surface modification of HNTs, particularly with PEI, effectively improves dispersion, matrix–filler adhesion, and the thermomechanical performance of nanocomposites.
Jang et al. (Thu,) studied this question.