Mechanical,wear, and dielectric behavior of TiO2 reinforced high-density polyethylene composites

Almost fully dense high-density polyethylene (HDPE) reinforced with submicron-sized titanium dioxide (TiO₂) ceramic filler (up to 40 vol %) was fabricated using compression molding. More than 98.5% ρ_th (theoretical density) could be obtained for all the HDPE compositions and its measured density varied between 0.94 and 2.25 g cc⁻¹. The hardness of HDPE increased considerably from 32.6 to 69 MPa (i.e., by two times) with the addition of 40 vol % TiO₂. The compression strength (19.03–34.16 MPa) and modulus of elasticity (0.49–1.05 GPa) of HDPE were also found to increase with the addition of TiO₂ filler. However, the HDPE exhibited good ductility (59% strain) up to 20 vol % TiO₂ and it was reduced with the further addition of TiO₂. The strain decreased drastically to 7.6% for HDPE-40 vol % TiO₂. Addition of TiO₂ filler leads to a considerable decrease in wear rate and coefficient of friction (COF). The wear studies revealed that the HDPE-40% TiO₂ composite exhibited a low wear rate of 1.82 × 10⁻⁵ mm³ N m⁻¹ and COF of 0.13. The dielectric constant of HDPE (at 10 kHz) was also considerably increased from 5.31 to 20.02 with the addition of TiO₂ up to 40 vol %. Achievement of such high dielectric constant for HDPE materials is the highest ever reported for HDPE. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47610.