Tailoring the Mechanical Properties of Nanocellulose/ ABS Composites by Tuning the Grafting Density on Nanocellulose

The interfacial structure between nanofillers and polymer matrices plays a critical role in determining the overall performance of polymer nanocomposites. In this study, we explored how varying the grafting density of flexible poly(oxyethylene/oxypropylene)‐2‐propylamine (MPOEA) chains on cellulose nanofibers (CNFs) influences the mechanical and thermal properties of CNF‐reinforced Acrylonitrile–butadiene–styrene (ABS) composites. The grafted MPOEA chains formed interfacial layers around the CNFs, with higher grafting densities yielding more interactive interphases. As a result, compared with the unmodified CNF/ABS composite, the optimized composite (J‐100%) exhibited an approximately 26‐fold increase in tensile toughness, from 0.90 ± 0.24 to 23.62 ± 7.47 MJ m −3 , while maintaining a Young's modulus of 1.52 ± 0.30 GPa, which remained comparable to that of neat ABS (1.41 ± 0.03 GPa). Thermomechanical analysis indicated that the addition of CNFs reduced the thermal expansion of the composites, and although this effect diminished at higher grafting densities, the coefficient of thermal expansion (CTE) values remained lower than that of neat ABS, ranging from (133.9 ± 0.3) × 10 −6 K −1 for J‐0% to (157.2 ± 4.4) × 10 −6 K −1 for J‐100%, compared with (169.5 ± 7.7) × 10 −6 K −1 for neat ABS.