Preparation And Study Of Polymeric Matrix Composites With High Dielectric Properties

Electronic materials as the backbone of electronic components must be met many of the new requirements and new indicators in order to adapting changes in market.It also must have higher plasticity for facilitation and miniaturization of the device,but production cost constrains the processing of electronic materials.At the same time the needs of users challenge to the properties of the material. Polymeric matrix composites can meet a variety of requirements as a kind of new materials,With the deepening of the study,properties of materials is rising.In this paper,composite prepared by carbon black and barium titanate mixed epoxy resin.Study the effects of modified powder on the dielectric properties of composites and dielectric mechanism.Obtain composite materials with dielectric constant greater than 52,the dielectric loss is less than 0.08.Articles in the first chapter introduces the research status of polymer matrix composites,theoretical model and factors.It has guiding significance for this paper.The second chapter describes the experimental reagents and equipment in the experiment,introduces some simple principles and applications of the test equipment.In the third chapter,we study the modified barium titanate and coated carbon black.The surface groups of barium titanate modified by KH550 changed,it has better compatibility with the polymer.The dispersion of carbon black improve a lot after the oxidation. Especially oxided by nitric acid,group content of-OH and-COOH changed significantly.By electron microscopy and thermal gravimetric analysis,found that carbon black has many advantages like oxidation resistance,coated evenly and size unity.In chapter IV,CB/EP composites were prepared,we studied the impact of curing agent,CB content,coated thickness and doping on composite properties.The results show,these factors have a direct impact on the internal structure of the composite material,it has a complex influence on polarization and conductivity loss in materials.When the carbon black content increases,composites appear optimized structure,it has minimum loss,the polarization and conductivity caused by structural changes has a significant impact on material properties in low frequencies.Structural changes has greater impact on conductivity in low levels,polarization is more important in the other hand.With the increasing of CB content,polarization effects become increasingly,but when over the percolation threshold,conductance loss become the main one.The change of thickness of the cladding layer also have an impact on the structure of the material,the proportion between conductance influence and polarization impact is always changing.When doped some uncoated carbon black in the composite material,the small particles present three forms:agglomerates with the large particles, agglomerates each other and dispersed uniformly in the matrix.They form a connection between the particles,at the same time,material is restructuring.In the fifth chapter,we study the effect of filler content and lamination process for CB/BT/EP composite material properties.The results show,30%BT-30%CB composite material has a large number of dipole orientation polarization,establish polarization time is short and has low loss at high frequency.The increase of carbon black or barium would undermine this orientation polarization,dielectric constant will decreases.When carbon black and barium carbonate is added to a certain amount,with increasing spatial polarization will produce another orientation polarization.However,it has different mechanism of this polarization,establish polarization time is long and has obviously fluctuation with frequency. Its contribution to the dielectric properties of the composite material is weaker than the first one.In lamination process,we find B/C/B model has good dielectric properties.With the increase of BT/EP layer and CB/EP layer,the dielectric constant of the composite material has greatly improved while the dielectric loss is reduced.Especially the increase of CB/EP layer enhance the dielectric properties of the composites is more obvious.