| As the electronic components in integrated circuits become more and more intensive,the electronic components in high frequency will generate more heat;The accumulation of heat is bound to affect the performance of the product,.Therefore,in order to ensure the normal and efficient operation of electronic equipment,high thermal conductivity polymer materials which can rapidly dissipate the accumulated heat are needed;In this paper,boron nitride(BN)was used as thermal conductive filler to fill the resin matrix to prepare the composites with high thermal conductivity.The research contents and results are as follows:1?First,the boron nitride / polyvinyl alcohol(BN/PVA)hydrogel was prepared by the ice template method,then the BN/PVA aerogel was obtained by freeze-drying,and then the BN/PVA composite was prepared by hot pressing operation of BN/PVA aerogel.When the content of BN in the composites is 31.73 wt%,the in-plane thermal conductivity can reach 3.45 W/m K,which is one of the relatively high thermal conductivity reported in the research of the same content of BN thermal conductive composites;When the content of BN/PVA composite reaches 67.74 wt%,the in-plane thermal conductivity can reach 10.04 W/m K.The results showed that when the BN/PVA hydrogel was frozen,the BN chips were extruded on the ice crystal interface due to phase separation,and the initial arrangement was completed.Secondly,through the hot pressing of the BN/PVA aerogels after freeze drying,the gap in the composites is reduced,and a good thermal contact between the BN sheets is formed.The preparation method of the composite improves the arrangement of BN sheet in the matrix and the utilization rate of thermal conductive filler.2?The effects of BN with different particle sizes on the properties of thermal conductive composites were studied.The BN/PVA composites were prepared by tape casting BN/PVA suspensions with two different particle sizes and hot pressing the BN/PVA films.The results show that the effect of BN with different particle sizes on the thermal conductivity of PVA matrix composites is the same,which increases with the increase of BN content;However,under the condition of the same filling mass fraction,the thermal conductivity of the composites with small BN particle size is better than that with large BN particle size.This is mainly due to the fact that in the PVA matrix dispersion system,the BN with small BN particle size has a greater chance to contact each other,and the increased contact between the BN particles will inevitably form more heat conduction network chains,So the thermal conductivity of BN/PVA composite can be further improved.The preparation of composite materials by tape casting is simple,rapid,low cost and has a wide application prospect.3?The effects of plasma modification on the thermal conductivity of BN/resin composites were studied.The properties of thermal conductive composites are not only related to the thermal conductive filler and resin matrix,but also closely related to the interface compatibility between them.According to the principle of similar solubility,the two phases with similar polarity have better interfacial compatibility.The compound was dissociated into free radicals in the gas phase by plasma discharge treatment,and then deposited on the surface of BN to form a coating film;The two molecular segments of the coating film and the resin matrix infiltrate each other at the two-phase interface to form a good adhesion,which improves the situation that the traditional filler is difficult to be compatible with the resin matrix and the dispersion is uneven,and further improves the thermal conductivity of the composite,and it provides a reference for the preparation of efficient thermal conductive materials. |
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