Improved Thermal and Structural Performance of LDPE Reinforced With Bamboo Cellulose Nanocrystals via PE-g-MA Compatibilization

Abstract

This study investigates low-density green polyethylene (LDPE) nanocomposites reinforced with bamboo-derived cellulose nanocrystals (CNCs) and compatibilized with polyethylene-graft-maleic anhydride (PE-g-MA). Four materials were prepared by melt extrusion and injection molding (neat LDPE; LDPE with 1.0 and 1.5 wt% CNCs; and LDPE with 1.0 wt% CNC + 1.0 wt% PE-g-MA) and evaluated by thermal, mechanical, and structural analyses. Fourier-transform infrared spectroscopy (FTIR) indicated interactions between maleic- anhydride groups and CNC hydroxyls, supporting improved interfacial compatibility. X-ray diffraction (XRD) showed increased crystallinity in CNC-containing samples, consistent with a nucleating effect. Thermogravimetric analysis/derivative thermogravimetry revealed single-step LDPE decomposition with an upward shift of the degradation-rate peak upon CNC addition; residues remained below 2 % at these low loadings. Under uniaxial tension, stiffness increased significantly at 1.5 wt% CNC and in the compatibilized composite, while tensile strength improved only with PE-g-MA; elongation decreased with CNCs irrespective of compatibilizer, remaining highest for neat LDPE. After accelerated aging (UV + humidity), modulus and strength exhibited modest declines across all materials, comparatively larger in the compatibilized system, suggesting time-dependent changes at the CNC-matrix interface. Overall, bamboo-CNC/PE-g-MA provides a sustainable route to tailor thermal performance and load-bearing response of LDPE for applications that prioritize stiffness and thermal resistance over ductility.