Improved synthesis of oligomeric phthalonitriles and studies designed for low temperature cure

Abstract

An improved synthetic method has been developed for oligomeric aromatic ether ketone‐based phthalonitrile (PN) resins. A new curing additive was studied that lowers the cure temperature of the PN resin to around 150 °C and compared to the traditional high‐temperature aromatic diamine. Mechanical and thermo‐oxidative analyses of polymeric samples from both systems were determined and compared under various curing conditions. The PN polymer exhibited low water absorption regardless of the chosen cure system. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1662–1668

Synthesis of bisphenol A‐free oligomeric phthalonitrile resins with sulfone and sulfone‐ketone containing backbones

“…6 Three classes of resins have emerged from this research; cyanate esters, 7,8 polyimides, and phthalonitriles (PN). 9,10 Cyanate esters are a class of resins that are easy to process, cure at low temperatures, and can exhibit high T g s, but suffer from long term hydrolytic stability issues and have upper temperature limits around 400 8C. 11 Polyimides, on the other hand, are more difficult to process than other resins, although they have a high T g , long-term thermal stability and good mechanical properties.…”

“…The PN resins are prepared through a two-step, one-pot nucleophilic displacement reaction between activated or unactivated dihaloaromatic compounds and an appropriate bisphenol, followed by end-capping with 4-nitrophthalonitrile. 10,[20][21][22][23] More recently, we have developed an improved synthesis of a sulfonyl-containing PN resin composition by reacting 4-(chlorophenyl) sulfone with an excess of bisphenol A followed by end-capping with 4-nitrophthalonitrile. 23 Although this PN resin had excellent properties, the inclusion of bisphenol A limited the thermal stability to 400 8C.…”

The curing behavior and properties of phthalonitrile resins using ionic liquids as a new class of curing agents

“…Then they were heated in distilled water for 48 h at 100°C, and the weight increases were noted. The maximum amount of water absorbed over this time period were approximately 3.24 and 6.89% by weight for Resin-1 and Resin-2, respectively, which were relatively higher than PN cured by aromatic diamine [1]. The result indicated that the content of [EPy]BF 4 , as a kind of ILs easy to absorb water, has an influence on the water absorption of resulting resins.…”

“…These excellent high-temperature properties make the PN resins attractive for many military and civilian advanced technological applications, such as composite matrices [3,4], adhesives [5], electrical conductors [6], and carbon precursors [7]. However, the polymerization of neat PN compound is extremely sluggish, the high curing-temperature of PN resins limited their further applications [1]. In order to address this problem, considerable research efforts have been expended on the development for the curing agent.…”

“…As a class of high-temperature/performance polymer, phthalonitrile (PN) resins have many excellent properties such as high thermal and oxidative stability, flame retardance, the absence of a T g before the thermal decomposition temperature, water and chemical resistance [1,2]. These excellent high-temperature properties make the PN resins attractive for many military and civilian advanced technological applications, such as composite matrices [3,4], adhesives [5], electrical conductors [6], and carbon precursors [7].…”