A facile method for the preparation of aliphatic main-chain benzoxazine copolymers with high-frequency low dielectric constants

Abstract

The designed aliphatic main-chain benzoxazine copolymer oligomers were synthesized by the Mannich reaction. It should be noted that increasing the ratio and polarity of a polar solvent is an effective strategy to prepare an aliphatic main-chain copolymer oligomer with a relatively satisfactory dispersity index (2.63). Accordingly, a copolymer prepared under the optimized toluene/N,N-dimethylformamide heterogeneous solvent conditions has the highest glass transition temperature (195 °C) and the minimum high-frequency dielectric constants (2.65, 5 GHz; 2.54, 10 GHz). Therefore, this work not only provides a simple route for improving the processing and high-frequency dielectric properties of main-chain benzoxazine but also gives some insight into the effects of the polar solvent on the formation of copolymers.