Fluorine and silicon-containing main-chain type polybenzoxazine with low dielectric constant and high thermal stability

Abstract

In this work, a fluorine and silicon-containing main-chain type benzoxazine (BAF-aptmds) was synthesized from bisphenol AF, 1,3-bis(aminopropyl)tetramethyldisiloxane (APTMDS) and paraformaldehyde. As a control, bisphenol A/APTMDS based benzoxazine (BA-aptmds) was synthesized. The hydrophobicity, thermal properties and dielectric properties of the two polybenzoxazines, PBAF-aptmds and PBA-aptmds, were investigated. The results showed that both polybenzoxazines had high hydrophobicity and low water absorption. Due to the presence of trifluoromethyl groups and siloxane segments, PBAF-aptmds was endowed with excellent low dielectric properties with a dielectric constant of 2.51 and a dielectric loss of 0.0053 at 1 MHz. Meanwhile, PBAF-aptmds exhibited high thermal stability with a glass transition temperature of 286 °C. In addition, the volume polarizabilities and the free volumes of polybenzoxazines were calculated by molecular simulation, which could help to further understand the relationship between their molecular structures and dielectric properties.