Preparation and Characterization of Cyanate Ester Copolymers Incorporating Naphthalene and Diaryl Ether Structure

ABSTRACT Cyanate ester resins are widely applied in technological fields such as aerospace and electronic information, attributed to their excellent dielectric properties, thermal stability, mechanical performance, and flame retardancy. With the rapid development of microelectronic technology, there is an urgent demand for further improvement in the comprehensive properties of the cyanate ester resins. In this study, a dicyanate ester monomer containing a naphthalene ring and diaryl ether (BCPON) was synthesized and copolymerized with bisphenol A dicyanate ester (BADCy), and the structure and properties of the resulting copolymers were systematically investigated. The results indicated that the BADCy/BCPON copolymer resin exhibited higher thermal stability, lower dielectric properties, and better dimensional stability compared with pure BADCy resin. Specifically, the 5% weight loss temperature of the BADCy/BCPON resin with 20 wt% BCPON reaches 434.8°C, which is 15.3°C higher than that of the pure BADCy resin (419.5°C). At a frequency of 10 GHz, the dielectric constant and dielectric loss of the copolymer resin with 30 wt% BCPON decrease to 2.79 and 0.0124, respectively, corresponding to a reduction of 4.5% and 17.9% compared to pure BADCy resin (2.92 and 0.0151). Additionally, the coefficient of thermal expansion (CTE) of the copolymer resin with 30 wt% BCPON in the temperature range of 40°C–220°C decreases from 65.6 ppm/°C (pure BADCy resin) to 61.6 ppm/°C. The BADCy/BCPON copolymer resin exhibits excellent comprehensive properties, which is expected to facilitate the development of high‐performance copper‐clad laminates and resins for electronic packaging.