Preparation of Negative Thermal Expansion ZrW2O8 Powders and Its Application in Polyimide/ZrW2O8 Composites

Negative thermal expansion (NTE) ZrW2O8 powders were prepared by step-by-step solid-state reaction with ZrO2 and WO3 powders. The coefficient of thermal expansion (CTE) of the as-prepared ZrW2O8 was around −5.08×10−6 K−1 at 20–700°C. Different amounts of ZrW2O8 powders were added in BTDA-ODA polyamic acid to form polyimide/ZrW2O8 composites (PI/ZrW2O8). With the increment of ZrW2O8, experimental results show that ZrW2O8 powders can significantly enhance the thermal stability of the composites, and reduce the thermal expansion. A 50 wt pct ZrW2O8 addition can give rise to a 31% reduction of CTE. It is suggested that the PI/ZrW2O8 composites have potential applications in high performance microelectronic devices.