Effect Of Nanodiamond Composite Fillers On Properties Of Epoxy Resin

Thermal conductive polymer materials play an irreplaceable role in chemical equipment,aerospace,electrical packaging and other modem high-tech fields due to its excellent thermal insulation property.It is a new type of thermal conductive material,and it has broad prospects for development.In addition to the excellent mechanical properties of polymers,thermal conductive polymer composites can improve the thermal conductivity of polymer materials to a certain extent.Generally most of polymer have poor thermal conductivity,thermal conductivity of epoxy resin is only 0.20W/(m*K)at 25oC.Preparing high polymer materials with high thermal conductivity and excellent performance has become a hot issue in the field of electronic packaging.In order to develop low cost and high thermal conductivity composites,boron nitride and nanodiamond were used as conductive composite filler,and high thermal conductivity of epoxy resin composite material with more excellent properties were prepared.Applications such as thermal conductivity tester,pull and compression machine and SEM were used for analyzing the thermal conductivity,mechanical properties and thermal stability of the composites.And the effects of surface modification,the ratio of composite fillers and the amount of filler on the properties of composites were studied.Firstly,MgO/ND,Al2O3/ND,BN/ND are used as composite filler,Then the effect of the type of thermal conductive filler on mechanical and thermal property is analyzed.It is found that the tensile strength and elongation at break of epoxy composites were decreased with the addition of thermal conductive fillers.The tensile strength of 37%Al2O3+3%ND/EP,37%BN+3%ND/EP,37%MgO+3%ND decreased 44%,47%,52%compared with pure epoxy resin.And thermal conductivity of EP composite material increased,the thermal conductive coefficient of 37%BN+3%ND/EP is the highest,which can be amount to 0.4769 W/(m K).Base on the experimental research,BN/ND were used as composite filler,and the optimum condition for preparation of thermal EP composite was determine through orthogonal experiments:the mass ratio of filler to EP was 5:5,the mass ratio of BN to ND was 10:1,the mass ratio of diluent to EP was 1:2,curing temperature was 65?,the dosage of curing agent was leq.Under this condition,the thermal conductive coefficient of BN+ND/EP was up to 1.3 W/(m·K).It is found that the tensile strength of the BN+ND/EP decreased 45%compared with pure epoxy resin,but the 5%weight loss temperature was increased 19oC compared with pure epoxy resin,since decompose temperature of diamond is above 800?.To sum up,BN+ND/EP composites have broad application prospects in the field of sophisticated electronic equipment due to its excellent thermal conductivity and mechanical properties.