Preparation And Properties Of Poly(Ether Ether Ketone) Resin Matrix Composites For Circuit Board

With the improvement of information technology,electronic products have changed to be flexible,multifunctional and lightweight.Especially with the development of 5G technology,the communication band has moved towards high frequency,which put forward higher requirements for copper clad laminate,the base material,such as lower dielectric constant,dielectric loss and higher thermal conductivity.Among them,the dielectric constant affects the transmission speed of the signal;high dielectric loss will cause signal distortion;circuit board substrate also generates a lot of heat at high frequency,which needs to improve the thermal conductivity to dissipate heat.In addition,the thermal expansion coefficient of the circuit board substrate,the bonding strength of copper foil and water absorption also have more requirements.In the traditional circuit board field,materials such as polyester and polyimide are often used as substrates.In order to cope with applications of high frequency,fluorine resins have attracted attention because of their excellent dielectric properties,but they cannot be used in practice because of their poor mechanical properties.Therefore,it is significant to prepare the circuit board substrate with the electrical and mechanical properties meeting the use requirements through the composite modification of poly(ether ether ketone)resin and fluorine resins.In this work,the blends of Polytetrafluoro ethylene(PFA)and PEEK were used as matrix materials,and low dielectric inorganic fillers were introduced into the system to study the effect of filler content on the properties of the composites.Then through the modification of the fillers,the PEEK resin matrix composites meeting the requirements of the circuit board were prepared.Firstly,a series of PFA / PEEK blends were prepared by melt blending,and 15wt% PFA / PEEK blend with the best comprehensive properties was used as resin matrix.Then CQF / PFA / PEEK,BN / PFA / PEEK and CQF / BN / PFA / PEEK composites were prepared by filling different content of short cut quartz fiber(CQF)and hexagonal boron nitride(BN),respectively,and the influence of the content of fillers on the properties of the composites was explored.The results show that CQF and BN,due to their high heat resistance,high strength and high modulus,restricted the movement of molecular chain,and improved the dimensional stability,thermal conductivity,thermal stability and storage modulus of the composite.And with the increase of the filling amount,the properties of the composites were further improved.When the content of CQF was 15wt% and BN was 5wt%,the linear expansion coefficient of the composite was the lowest,which was 36.1% lower than matrix,the thermal conductivity was 61.9% higher than matrix,and the tensile strength is 13.8% higher than matrix.However,due to the interface polarization between CQF and BN and the matrix,the dielectric properties of the composite decreased.In order to further improve the dielectric properties and dimensional stability of the materials,the fillers were modified under the same filling content.In this work,CQF and BN were grafted by silane coupling agent KH550 and wrapped by polyetherimide(PEI),which has good compatibility with PEEK,to obtain surface modified f-CQF and m-BN.Then,f-CQF / PFA / PEEK,m-BN / PFA / PEEK and fCQF / m-BN / PFA / PEEK composites were prepared and the effect of surface modification of fillers of composites properties was studied.The results show that the surface modification of fillers improved the compatibility between fillers and matrix and promoted their uniform dispersion in matrix.Then,the dielectric properties,dimensional stability,thermal conductivity,mechanical properties and storage modulus of the composite were improved.When the content of f-CQF was 15 wt% and m-BN was 5 wt%,the linear expansion coefficient of the composite was the lowest,26.46 ppm/K,which was 15.4% higher than that of the unmodified composite,similar to the linear expansion coefficient of copper 17.7 ppm/K,and its dielectric constant was also reduced by 11.8%.The comprehensive properties meet the requirements of the circuit board substrate and can be used in the field of three layers of flexible copper clad laminate(3-FCCL)and two layers of flexible copper clad laminate(2-FCCL).