Due to the advantages of long use time,energy saving and environmental protection,LED develops rapidly and is widely applied in display and lighting fields such as large scale display and white light illumination.Nowadays,epoxy resin is one of the most common used packaging materials for LED devices because of its low cost and excellent properties.However,it's characteristic of large thermal expansion coefficient (CTE) usually causes inconsistency of thermal expansion behaviors between the chip or other metal parts inside the LED and packaging materials during using,which may cause damage to the LED chip and finally resulting in the failure of devices or other reliability issues.In order to reduce the thermal expansion coefficient of LED packaging materials,negative thermal expansion powder of tungsten zirconium phosphate (ZWP) was synthesized by microwave hydrothermal method,which was filled into bisphenol A epoxy resin to prepare ZWP/E-51 epoxy composites with different filling content.The effect of microwave hydrothermal process on the morphology,structure and property of ZWP powder was studied.And the thermal expansion properties,optical and thermodynamic properties of epoxy composites under different filling contents were also studied.The main results showed that:(1)compared with hydrothermal method,the ZWP powder prepared by microwave hydrothermal method was smaller and more uniform in size,giving better property of negative thermal expansion;(2)With the increment of ZWP powder,the thermal expansion property of ZWP/E-51 was improved significantly,and a 40wt% ZWP loading gave a 42.7% (about 30.5×10-6/℃) reduction of CTE at a temperature range of 30～90℃.And in addition,ZWP/epoxy composite with 10wt% loading showed better comprehensive properties.
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