Preparation And Properties Of Surface Modified Zr₂WP₂O₁₂ And Zr₂WP₂O₁₂/PI Composite Material

In order to obtain a polyimide?PI?-based composite material with low thermal expansion coefficient and low dielectric constant for electronic packaging,Zr₂WP₂O₁₂?ZWP?particles modified by the silane coupling agent KH570 were added to the PI matrix by in-situ compounding.The effects of surface treatment on the morphology,thermal expansion properties and dielectric properties of the composite materials were studied.The reaction process and mechanism of the modified ZWP?m-ZWP?were studied using X-ray diffractometer?XRD?,Fourier transform infrared spectrometer?FTIR?and contact angle measuring instrument.The results show that after modification,the contact angle of ZWP increases,from hydrophilic to hydrophobic,but the addition of KH570 does not change the crystal structure of ZWP.The adsorbed water stored on the surface of the ZWP particles provides hydroxyl groups for the modification of the silane coupling agent,and an association reaction occurs with the silanol after the coupling agent is hydrolyzed,and a water molecule is removed to form a hydrogen bond.Scanning electron microscope?SEM?,dilatometer and impedance analyzer were used to characterize the performance of ZWP/PI composites before and after coupling agent modification,and the following research results were analyzed:1.The negative expansion curve of the ZWP sample prepared by hydrothermal method at RT-400?,the average linear expansion coefficient is calculated to be-5.01×10^-6/K,and the expansion coefficient of the ZWP sample prepared by solid phase sintering method at RT The expansion coefficient in the range of-400?is-2.2×10^-6/K.The data of the sample with variable temperature XRD test shows that the volume expansion coefficient?_v=-4.6946×10^-6/K is calculated within the temperature range of 30-300?.The ZWP sample prepared by hydrothermal method has a larger negative expansion coefficient than the sample prepared by solid phase sintering method,and the negative expansion coefficient of ZWP prepared by hydrothermal method is closer to the intrinsic expansion coefficient.In the composite experiment,a larger negative expansion coefficient can reduce the thermal expansion coefficient of PI more,which is beneficial to the application to the microelectronics industry.2.Before the coupling agent is used,the ZWP powder will be directly dissolved in water;after the coupling agent is added,the silanol hydrolyzed by the coupling agent reacts with the adsorbed water on the surface of the ZWP to form a hydrogen bond,and the other end of the coupling agent is organic The functional group is oleophilic and will float on the water when it comes into contact with water.The contact angle test results show that when the addition amount of the silane coupling agent KH570 is0.50wt.%,the dispersibility of the m-ZWP sample is improved,and the contact angle increases from 2.46°to 134.39°.3.There will be adsorbed water on the surface of general inorganic substances.The silane coupling agent can react with the surface moisture to form silanol groups.This group can also form strong hydrogen bonds with the hydroxylated surface.The Fourier infrared test results show that the characteristic peaks of KH570?C=O,C=C and-CH₃?appear on the m-ZWP line,respectively 1716 cm^-1,2840 cm^-1 and 2940cm^-1.The results show that the surface modification is successful.4.The thermal expansion data of the sample modified by the coupling agent shows that the coupling agent effectively reduces the thermal expansion performance of the composite material ZWP/PI.KH570 has the most excellent modification effect on composite materials.When the addition amount of silane coupling agent KH570 is0.5wt.%,the expansion coefficient of the modified ZWP/PI composite samples in the RT-300?range is 28.47×10^-6/K,which is 50.04%lower than the pure PI(56.99×10^-6/K)of the control sample of the same group of experiments.5.The test results of the impedance analyzer show that different proportions of KH570 can effectively adjust the dielectric properties of PI.The dielectric constant of PI?_PI=3.28,and the sample with the addition amount of silane coupling agent KH570of 0.25 wt.%had a dielectric constant of 2.5,which reduced the dielectric constant of PI.The dielectric constant of the copper clad laminates produced now is about 2.7.A smaller dielectric constant can make the signal propagation faster.