Role of interface on dynamic modulus of high‐performance poly(etheretherketone)/ceramic composites

High‐performance printed circuit board or electronic packaging substrate with low warping particularly at high frequency is the key demand of manufacturers. In the present work, poly(etheretherketone) (PEEK) matrix composites reinforced with untreated micron size aluminum nitride (AlN) and alumina (Al 2 O 3 ) particles have been studied for dynamic modulus in the temperature range varying from 30 to 250°C. At 48 vol % particles, the room temperature modulus of the PEEK/AlN composites increased by approximately fivefold (∼ 23 GPa), whereas it increased by twofold for PEEK/Al 2 O 3 composite. The reinforcing efficiency is more pronounced at higher temperatures. The significant improvement in modulus was attributed to the better adhesion between the matrix and the AlN particles. Scanning electron microscope (SEM) and Kubat parameter showed that the poor adhesion between the matrix and the Al 2 O 3 particles resulted in comparatively smaller increase in modulus of PEEK/Al 2 O 3 , despite higher intrinsic modulus of Al 2 O 3 than that of AlN. SEM showed almost uniform distribution of particles in the matrix. The experimental data were correlated with several theoretical models. The Halpin–Tsai model with ξ (xi) is equal to four correlates well up to 48 vol % AlN composites while ξ is equal to two correlates only up to 18 vol % Al 2 O 3 composites. Guth–Smallwood model also correlates well up to 28 vol % AlN and 18 vol % Al 2 O 3 ‐filled composites. Thereafter, data deviated from it due to the particles tendency to aggregate formation.