Enhanced Strength and Dimensional Stability of ABS via Shape‐Dependent TiO ₂ Whiskers Reinforcement

ABSTRACT Incorporation of various fillers alleviated acrylonitrile butadiene styrene (ABS) die swell but significantly reduced strength, with an urgent need for improved fillers. Further research is required on the extrusion rheological behavior disparities between nanosized whisker‐filled and spherical nanoparticle‐filled polymer composites. Herein, two rutile TiO 2 nanostructures, nearly‐spherical (ST) and rod‐like (RT), were melt‐blended with ABS to prepare nanocomposites, with their performance studied. RT simultaneously enhanced strength and dimensional stability, outperforming ST and other whisker fillers reported in the literature. Compared to ST, RT better enhanced the stiffness, dielectric constant, and heat resistance of ABS. Specifically, with 30 wt% RT, the tensile/flexural strength and modulus, dielectric constant, and heat deformation temperature were increased by 25%/9.7%, 176%/152%, 85.2%, and 6.2%, respectively. DMA confirmed the stronger stiffening and restrictive effect of RT. The strengthening mechanism of RT/ABS was associated with whisker pulling out and breaking, accompanied by matrix deformation. Dimensional stabilization resulted from a combination of the high confinement effect from high surface area and the shaping of sleeve‐like tubular skin‐core structure from high aspect ratio. The application of Halpin–Tsai, Ostwald–de Waele, and Carreau models offered theoretical validation of RT's stiffening effect, composite fluidity, and high dimensional stability imparted by RT.