Preparation of high-performance hyperbranched polybenzoxazine with low dielectric constant

Abstract

A high-performance hyperbranched polybenzoxazine with low dielectric constant was prepared. A hyperbranched benzoxazine (HTTr-d) was synthesized from 1,1,1-tris(4-hydroxyphenyl) ethane, 1,12-dodecanediamine and paraformaldehyde through an A₂ + B₃ approach with p-tertbutyl phenol as an end-capping reagent. After thermal curing, hyperbranched polybenzoxazine (PHTTr-d) was obtained. For comparison, trifunctional polybenzoxazine (PTr-s) with long alkyl groups was also synthesized. The introduction of long alkyl chains can effectively reduce the dielectric constants of polybenzoxazines. Due to the presence of tertiary butyl groups and the forming of hyperbranched structure, the dielectric constant of PHTTr-d was 2.59 at 1 MHz, which was lower than 2.68 of PTr-s. Compared with PTr-s, PHTTr-d exhibited higher thermal stability with the glass transition temperature (T_g) of 197 °C. These results indicated that the hyperbranched polybenzoxazine has potential application as a low dielectric constant material in the field of electronic information.