Preparation And Study Of Polyarylene Ether Nitrile/Modified Boron Nitride Thermal Conductive Composites

With the development of electronic devices,printed circuits and other fields,equipment miniaturization and high power are required,therefore,materials with high insulation,workability and high thermal conductivity are required.The polyarylene ether nitrile(PEN)has excellent properties,such as high insulation,high toughness and high thermal stability.It has great application prospects in the fields of electronic devices and aerospace.However,the PEN with low thermal conductivity and high coefficient of thermal expansion can not directly meet the needs of the industry.The thermal conductive polymer composites can make up for the shortcomings of single polymer material and have new excellent properties.The hexagonal boron nitride(h-BN)is a two-dimensional insulating material with high thermal conductivity,high insulation and other properties.It is the research focus of high insulation and thermal conductivity materials in recent years.However,the non-modified BN is not uniformly dispersed in the polymer matrix and has poor interfacial compatibility with the matrix,which directly affects the properties of the composites.Therefore,the surface modification of boron nitride is very important.Firstly,the PEN terminated with phthalonitrile was synthesized.The sulfonated polyarylene ether nitrile(SPEN)was produced as h-BN surface modifier.The core-shell BN@SPEN was prepared by ultrasonic method combined with the post-treatment bonding process.The BN@SPEN fillers were added in the PEN to prepare the BN@SPEN/PEN composite films by solution casting method.The DMA test results prove that composite films have low thermal expansion coefficient and high dimensional stability.The thermal conductivity of the composite films increase obviously because of the addition of BN@SPEN.When BN@SPEN filler is 20 wt%,the thermal conductivity of the composite films reach 0.69 W/(m·K),which corresponds to 2.4 fold to that of the PEN.Dielectric property measurements show that the composite films maintain high insulation.Secondly,because of the better heat transfer performance of single or several layers of nanomaterials,the h-BN was exfoliated into nanosheets by ultrasound in N-methyl-2-pyrrolidinone(NMP),and the dispersed solution of boron nitride nanosheets(BNNSs)in NMP was added into the PEN dissolved in NMP to prepare composite films by solution casting method.The SEM observation shows that some BNNSs have self-aggregation.The mechanical property test results show that the tensile strength and tensile modulus of the PEN are enhanced by BNNSs.Finally,in order to improve the self-aggregation of the BNNSs,organic groups are grafted on the surface of boron nitride for preparing g-BN.Based on the principle of crosslinking reaction of nitrile groups,the g-BN/PEN composite films were treated for 4hours at 340 ~oC to increase the interfacial compatibility between BN and PEN matrix.The DSC,TGA and DMA results show that the g-BN can improve the thermal stability of the composite films.Dielectric property and thermal conductivity measurements show that the insulation of the PEN is not reduced.When the g-BN filler is 16 wt%,the thermal conductivity of the composites is 0.74 W/(m·K).In this paper,it can be seen that the modified h-BN can not only improve the thermal conductivity and reduce thermal expansion coefficient of the PEN,but also maintain the insulation and high thermal stability of the PEN.Therefore,the PEN has potential applications in the field of electronic devices.