High microwave dielectric constant and improved thermal stability of functionalized Zn0.15Nb0.3Ti0.55O2-filled polyolefin composites

This paper investigated the structure, microwave dielectric properties and thermal properties of xZn _0.15Nb _0.3Ti _0.55O ₂ @VTMS/polyolefin composites in the range of x = 83–91 wt%. Zn _0.15Nb _0.3Ti _0.55O ₂ (ZNT) powder underwent conventional sintering process before being laminated with 1,2-PB/EPDM/SBS through hot-press process after being modified by Vinyltrimethoxysilane (VTMS). In this study, we analyzed the surface character, microstructure, microwave dielectric properties and thermal performances of the composite material. The findings indicate that a core-shell structure was formed to enhance the compatibility between ceramic particles and polyolefin matrix. Furthermore, the modified ceramic formed an interfacial layer with resin matrix that limited the movement of resin chain segments and improved the thermal stability of the composites. However, further increase of ceramic content more ceramic agglomerates and pores introduced more ceramic agglomerates and pores resulting in reduced cross-linking density of the resin. Consequently, a high-D _k composite was obtained when x = 89 wt% at 10 GHz: D _k = 16.79, D _f = 0.0023 and τ ε = −120 ppm/℃, which is promising for microwave applications.