Synthesis of copolymers based on divinylbenzene and dibenzocyclobutyldimethylsilane and a study of their functional characteristics

Abstract

Objectives. To create new polymer materials based on organosilicon derivatives of benzocyclobutene and to study the possibility of their use as insulating dielectric layers in micro- and microwave electronics devices.Methods. The synthesis of the dibenzocyclobutyldimethylsilane (diBCB-DMS) monomer was carried out from 4-brombenzocyclobutene through the production stage of the Grignard reagent. Copolymers based on divinylbenzene and dibenzocyclobutyldimethylsilane were obtained by means of thermal polymerization. The properties and structure of the copolymers thus obtained were studied using the following methods: thermogravimetric analysis, infrared spectroscopy, nuclear magnetic resonance (NMR), mass spectroscopy, and by means of high-frequency measurements of volt-ampere characteristics and volumetric resonator.Results. diBCB-DMS was synthesized with a yield of 81.5%. The composition and structure were confirmed by 1H and 13C NMR spectroscopy. The dielectric constant of the diBCB-DMS homopolymer is ~2.6. The tangent of the dielectric loss angle at 1 GHz of the diBCB-DMS homopolymer is 2.3∙10−4. The tangent of the dielectric loss angle at 10 GHz of the diBCB-DMS homopolymer is 2.6∙10−4. The study of divinylbenzene and diBCB-DMS copolymers in different molar ratios on a thermogravimetric analyzer showed that the copolymers are able to withstand temperatures up to 470°C. The dielectric permittivity of diBCB-DMS and divinylbenzene copolymers in a molar ratio of 1 : 1 was 2.6. The values of the loss tangent at 1 and 10 GHz of copolymers in a molar ratio of 1 : 1 were 4.0∙10−4 and 5.6∙10−4, respectively.Conclusion. Analysis of the obtained results shows that the samples of the diBCB-DMS homopolymer have the same dielectric characteristics as the samples based on diBCB-DMS and divinylbenzene, therefore, the introduction of divinylbenzene into the polymer structure does not worsen the dielectric parameters and such polimer materials can be used at high temperatures.