Research On The Non-thermal Effect Of Microwave And Its Application In The Preparation Of Multifunctional Electromagnetic Shielding Materials

Microwave curing is a fast and effective curing technology that the microwave radiation is generates energy to chemically crosslink the resin to form a three-dimensional network.It has the advantages of uniform curing,fast speed,easy control,and energy saving,and improves material performance.At present,there are still different controversies about the mechanism of microwave irradiation.The main problems are:whether there is a "non-thermal effect" in microwave radiation,how does affect the reaction process,how to improve the efficiency of microwave utilization,and how to use microwave to prepare high-performance material.In this project,through the quantitative characterization and mechanism research of the "non-thermal effect",and the further use of the non-thermal effect of microwave energy distribution mechanism,the microwave irradiation improves the filler surface wettability and excellent interface bonding,and induces the generation of a flexible interface layer.Excellent absorbing electric/magnetic nano-reinforced material’s electrical and thermal conductivity synergy and the combination of two-dimensional graphene oxide nanosheets and zero-dimensional nano-barium ferrite’s multi-dimensional and multi-scale combination,in-depth study of the interface between the reinforcement and the matrix in the composite material Performance and synergy between reinforcements and other aspects,to achieve high dispersion stability of multi-dimensional nano reinforcements in resins and higher functional performance requirements of composite materials as electromagnetic shielding materials,from the perspective of designing the structure/performance of multifunctional materials Set out,the use of advanced microwave curing mechanism to build a well-dispersed,strong electromagnetic shielding characteristics and multi-functional three-dimensional network composite materials,promote the application of microwave in the field of resin/composite materials and improve the performance of resin and composite materials.The main research contents of this paper are as follows:(1)In the second chapter,we constructed an isothermal microwave curing reactor to track the reaction rate of the resin in the isothermal microwave curing reactor in real time,the effects of amine(D230)and acid anhydride(MHHPA)curing agents on bisphenol A epoxy resin were studied respectively.(DGEBA)The non-isothermal kinetics during the curing process and the enhancement mechanism of the mechanical properties of the cured product.By calculating the apparent activation energy,the non-thermal effect of microwave was quantitatively evaluated.As the reaction temperature decreases and the content of polar functional groups increases,the "non-thermal effect" becomes more obvious.DMA,TGA and mechanical tensile tests show that microwave irradiation selectively Activating polar functional groups produces a network structure that is not restricted by the migration of reactive groups,resulting in a higher degree of crosslinking.SEM observation of the fracture surface shows that microwave radiation increases the stress concentration area of resin curing.This chapter clearly discusses the non-thermal effects of microwave irradiation on EP-D230 and EP-MHHPA resins,which is beneficial to improve the efficiency of microwave applications and has guiding significance.(2)This chapter,based on the research of the "non-thermal effect" of microwave in the previous chapter,realizes that microwave irradiation can improve filler surface wettability and strong interface bonding,induce a flexible interface layer,increase resin crosslinking density,and enhance load stress transfer.Excellent absorbing electric/magnetic nano-reinforced material’s electrical and thermal conductivity synergy and the multi-dimensional and multi-scale combination of two-dimensional graphene oxide nanosheets and zero-dimensional nano-barium ferrite,using nano-barium ferrite particles with a unique lattice structure It is combined with graphene to achieve impedance matching characteristics,produce high interface polarization loss,improve dielectric loss and magnetic loss capabilities,and enhance the thermal and electrical conductivity of composite materials.In-depth study of the interface performance between the reinforcement and the matrix in the composite material and the synergy between the reinforcements,etc.,to achieve the high dispersion stability of the multi-dimensional nanoreinforcement in the resin and the higher functional performance of the composite as an electromagnetic shielding material Requirements,successfully prepared high-performance thermal conductivity,hydrophobic and electromagnetic shielding materials.