Controlled synthesis and evaluation of cyanate ester/epoxy copolymer system for high temperature molding compounds

Abstract

Epoxy molding compounds (EMCs) have become an integral component for high power electronics to work under harsh environment nowadays. For high temperature operation, polymer networks with high glass transition temperature (Tg) are required to ensure device stability. In this work, high Tg polymers were designed via controlled incorporation of in situ formed and thermally stable triazine structures into epoxy matrix. Reactions involved in the copolymer system of cyanate ester and epoxy (CE/EP) were investigated. Increasing ratio of cyanate ester dramatically promoted Tg of the copolymer up to 275 °C with improved heat resistance. High temperature aging and moisture absorption tests revealed that hydrolysis of polycyanurate network and rearrangement of cyanurate occurred during aging, especially for copolymers with higher than 75% of cyanate ester. Based on thermal properties and aging performance, the composition of CE/EP system was optimized. The formulated bisphenol A cyanate ester and biphenyl epoxy copolymer system has great potential to be applied as high temperature encapsulation materials in electronic packaging. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1337–1345

Polyimide incorporated cyanate ester/epoxy copolymers for high‐temperature molding compounds

“…S3). The increasing intensity and broadened peak around 3200 cm −1 suggested the formation of –OH during hydrolysis, and the broaden peaks around 1700 cm −1 was due to the formation of carbonyl groups via thermo‐oxidation . Resins with different content of polyimide exhibited similar IR spectra after aging and was similar with that of CE/EP.…”

“…During the high‐temperature aging, volatile products released from the polymer network and resulted in a mass loss of the resins . The degradation of CE/EP polymer network involves the hydrolysis reaction of polycyanurate, which breaks the triazine network and produces small molecules of CO 2 and NH 3 . In the CE/EP‐PI system, the incorporation of polyimide reduced the overall mass loss of the resins as polyimide itself had an excellent thermal stability.…”

“…In the design and development of high‐temperature EMCs, glass transition temperature ( T g ) and thermal stability have been used to evaluate their potential high‐temperature application . With this criterion, efforts have been made to incorporate thermally stable chemical structures into epoxy networks by copolymerization, such as s‐ triazine rings, poly (ether sulfone), cyclic imide, and so forth. Having focused on the effects of copolymerized chemical structures in epoxy, studies rarely look into the influence of physically tuned polymer structures, such as polymer blends.…”

Thermal and water absorption properties of cyanate ester resins modified by fluoride‐containing and silicone‐containing components

“…According to literature reports, the introduction of silicon‐ and fluorine‐containing components could efficiently reduce the overall polarity and void content within the resin matrix, hence reducing the water absorption of the materials . More importantly, silicon‐containing resins exhibited excellent heat resistance, weather resistance, and electrical insulation, while fluorine‐containing resins also have advantages in heat resistance, dielectric properties, chemical stability, weather resistance, and nonflammability. These features were made silicon‐containing and fluorine‐containing resins suitable components for the modification of high temperature dielectric thermosets, and some successful examples were already realized in CE resins.…”

“…As mentioned above, fluorine‐ and silicon‐containing resins have demonstrated positive effect on the hygroscopicity of CE resins. However, comprehensive evaluation should be considered during the modification of CE resins, where the suppression of water absorption should not be realized at big costs of thermal and mechanical properties . Herein in this paper, a series of novel silicone‐containing and fluorine‐containing components were prepared and introduced into CE resins, and the water absorption, thermal, mechanical, and dielectric properties were systematically characterized.…”