Study On Preparation Of AlN/Epoxy Resin Composites And Performance On Low-temperature Insulation And Radiation Resistance

The epoxy resin composite material with high thermal conductivity,excellent mechanical properties and insulation properties is very important to ensure the stability of the superconducting coil in the low temperature and strong radiation environment.Epoxy resin has many excellent properties,but epoxy resin also has low intrinsic thermal conductivity(0.1～0.2 W/m K),brittleness at low temperature,high filling dispersibility and poor mechanical properties.In order to solve these problems,this paper adopts the solution blending method,uses aluminum nitride(Al N)with high thermal conductivity as the filler,and successfully prepares Al N@KH-560/E-51 resin composites by designing and synthesizing different structures.Al N@KH-560/alicyclic resin composite material and different content of cyanate ester/Al N@KH-560 composite material.By means of universal testing machine,SEM,TGA,DMA and broadband dielectric spectrometer,the mechanical properties,thermal conductivity,fracture morphology,thermal stability,and dynamic thermal properties of Al N@KH-560/epoxy resin composites have been systematically studied.Mechanical properties and dielectric properties.It is divided into the following three parts:(1)The silane coupling agent KH-560 was used to modify nano-Al N particles,and the structural changes of Al N nano-particles before and after the modification were explored through FT-IR,XRD,TGA,SEM and other means.The modified nano-Al N particles were successfully introduced into the E-51 epoxy resin matrix,and the curing reaction kinetics of Al N@KH-560/epoxy resin was studied.The characterization analysis of the modified Al N showed that the surface of Al N was successfully grafted with the silane coupling agent KH-560.When the content of Al N@KH-560 is 15 wt%,the tensile strength at 77 K is 88.67 MPa,which is 42.17%higher than the tensile strength at room temperature.When the content of Al N@KH-560 is 20 wt%,the thermal conductivity reaches the maximum,which is 0.5334W/m K.After filling Al N@KH-560 particles,the T_g of the composite material is slightly reduced.With the same filling amount of Al N@KH-560,the dielectric constant and dielectric loss of the sample at 77 K are lower than the dielectric constant and dielectric loss at room temperature.(2)In order to improve the electrical insulation performance of Al N composites at low temperatures,a cycloaliphatic resin with better dielectric properties and lower viscosity is selected to match the modified Al N nanoparticles.Successfully prepared Al N@KH-560/alicyclic resin composites with different contents,and the dielectric properties are better than Al N@KH-560/E-51 resin composites.When the content of Al N@KH-560 is 20 wt%,the thermal conductivity reaches the maximum,which is 0.4637 W/m K.The samples prepared by filling with 10 wt%Al N@KH-560 have the best thermal stability.The storage modulus of 10wt%sample is the largest at 2411 MPa,and the T_g at this time is the highest at 231.35℃.SEM shows that Al N@KH-560 is well dispersed in the alicyclic resin without obvious agglomeration.(3)On the basis of the previous two chapters,cyanate ester resin is introduced into E-51and alicyclic resin matrix to enhance the radiation resistance of composite materials.The cyanate ester/Al N@KH-560 composite materials with different relative contents were prepared.After irradiation,the breaking strength of the sample with a CE content of 40 wt%was the largest,which was 63.21 MPa,which was 32.52%higher than the sample without adding cyanate ester resin.When the CE content is 40 wt%,the dielectric constant of the sample reaches the lowest value at 10~3Hz,which is 3.75.The dielectric loss values of the irradiated samples are all lower than 0.08(10~2～10~6Hz),indicating that the dielectric loss performance of the irradiated samples remains excellent.