Preparation And Dielectric Properties Of BaTi₄O₉/MSR Composites

With the development of science and technology and industrialization, the information throughput is gettting larger and larger. The data handling capacity and the information transfer rate of electronic product are more and more requiring. The electronic product and the communicating product are getting more and more high-frequent, high-speed, integrated and miniaturized. The high-frequent PCB substrate is required to process large mount of information under super-high-frequency. The common PCB substrate is used to be structural component or connector, but the high-frequent PCB substrate can also be used to be functional part. The high-frequent PCB substrate needs to have proper and stable dielectric constant, low dielectric dissipation fraction, high heat-durability and wet fastness.In this paper, under the background of the application of super- high-frequent PCB substrate, ceram/polymer composites with adjustable dielectric constant, low dielectric dissipation fraction, exceleent processing property and ductility are wish to be prepared, which can be used at 300℃for long-term. MSR is used as matrix for its mechanical properties and resistance to elevated temperatures. BaTi₄O₉ with low dielectric dissipation fraction is used to be the filled ceramic phase. The content of ceramic phase is adjusted to get proper dielectric constant. Xylol is used to be dissolvant. BaTi₄O₉/MSR composites with different content of ceramic phase are prepared by solution mixing method, then the change of organization structure and dielectric properties are researched.We use dynamic DTA to calculate cure kinetic paramertrs of the BaTi409/MSR blends, and then determined the composites'curing process: 140℃/4h+160℃/2h+ 180℃/2h.The results show that the dielectric properites of BaTi₄O₉/MSR composites display stability to the change of frequence from 18⁴0GHz.The dielectric contants and dielectric loss tangent of BaTi₄O₉/MSR composites at 21GHz and room temperature grow up with the incresing of frequence, the tanδwere much lower than the MSR matrix's.The contents and distribution of the ceramic particles had an significant impact on the composites'dielectric properites.KH550 silance coupling agent can effectively improve the compatibility between the BaTi₄O₉ powders and the MSR,and then improve the composites'dielectric properites.The optimal fration of KH550 was 1.0wt%.At last,we use different model about the dielectric contants of composite materials to analysis the BaTi₄O₉/MSR comgposites. The results show that the commonly used empirical model is not suitable for BaTi₄O₉/MSR,Yamada and EMT equation were in good agreement to fitting the composites with the unmodified BaTi₄O₉,the shape factors were 3.47953 and 0.28989,respectively,while the modified composites'dielectric is more close to the Jaysundere model.