Low Dissipation High Performance Thermal Management Material System Construction And Mechanism Research

With the rapid iterative development of modern electronic devices,the operating power of electronic devices is growing exponentially.However,these electronic devices will continuously generate heat during use,and excessive heat accumulation will cause irreversible damage to the electronic devices.Therefore,effectively solving the problem of thermal conductivity and heat dissipation in the thermal management system of electronic devices is a major research challenge nowadays.Polymer materials are very good plastics for engineering applications because of their low cost,lightweight and corrosion resistance.However,the low thermal conductivity characteristics of polymer materials do not allow them to be directly applied as thermal management materials.To meet the application requirements of future thermal management material systems for electronic devices,the thermal conductivity of polymeric materials can be improved by adding high thermal conductivity fillers or modifications.Based on the above research background,this topic proposes the construction of low dissipation high-performance thermal management material system.Firstly,we studied and summarized the thermal conductivity mechanism of polymer composites,and constructed low dissipation polymer thermal management materials in different systems from the three perspectives of co-blended material system,effective network construction,and introduction of 3D printing to expand the application scenarios of thermal interface material system.The main studies are as follows,(1)The effects of different factors on the thermal conductivity mechanism in polymer composites are analyzed.From the heat conduction theory,the polymer thermal conductivity mechanism is discussed and the factors influencing the thermal conductivity of polymer materials are investigated,and finally,the theoretical model of thermal conductivity of polymer composites is discussed and compiled.(2)Based on the Spatial Confining Forced Network Assembly(SCFNA)method proposed by the group,hexagonal boron nitride/paraffin/polydimethylsiloxane(hBN/PW/PDMS)phase change composites(PCCs)with shape stability,high thermal conductivity and mechanical strength properties were prepared.The P8-4 PCC samples could achieve a thermal conductivity of 1.44 W/m-K and an enthalpy of melting of25.84 J/g when the contents of hBN and PW were 28.6 and 14.3 wt%.The prepared polymeric thermally conductive composites can effectively combine the fast heat absorption/exhaustion ability of phase change materials and effectively reduce the dissipation of thermal management system.(3)Based on the preparation of low-dissipation polymeric thermally conductive composites from the blended system,a method is proposed to first prepare an effective thermally conductive network and further combine it with a forced assembly process to construct low-dissipation polymeric composites with good thermal conductivity networks.The specific method uses directional freeze-drying to prepare hBN-PVA thermally conductive networks and further combines with forced assembly to prepare hBN-PVA/PDMS composites to obtain polymer composites with low dissipation and high thermal conductivity.(4)Both of the aforementioned prepared polymeric thermally conductive composites are in sheet form and can only be applied in two-dimensional thermal interface management material systems.In order to further expand the application scenarios of thermal management material systems,a polymer composite with excellent overall performance is proposed based on 3D printing of a mechanically loadable skeleton combined with a thermally conductive composite filler.