Synthesis and characterization of phthalonitrile resins from ortho -linked aromatic and heterocyclic monomers

Abstract

This article describes the synthesis and properties of phthalonitrile polymers prepared from three different ortholinked monomers, namely 2,2 -bis(3,4-dicyanophenoxy)biphenyl, 1,2-bis(3,4-dicyanophenoxy)benzene and 2,2 -bis(3,4dicyanophenoxy)-1,3,4-oxadiazole. The resins exhibited a low complex viscosity, with a varying range of processing temperatures for all three systems. Thermogravimetric analysis showed that the synthesized polymers exhibited high thermal and thermo-oxidative stability. The high char yields, which ranged from 64 to 69% at 900 • C under nitrogen atmosphere, and the high glass transition temperatures of the polymers indicated a high crosslinking density in the network structure. Dynamic mechanical measurements demonstrated that the fully cured monomer 2,2 -bis(3,4-dicyanophenoxy)-1,3,4-oxadiazole exhibited no change in glass transition temperature or in storage modulus up to 500 • C.

Branched phenyl‐s‐triazine moieties to enhance thermal properties of phthalonitrile thermosets

“…Growth in the aerospace, marine and microelectronic industries increasingly requires the development of heat‐resistant materials . Phthalonitrile (PN)‐based resins, as a class of heat‐resistant materials, have sparked great interest and attention, due to their unique properties, including outstanding thermal stability, great flame retardancy, low moisture resistance and excellent mechanical properties . A factor that has impeded the application of neat PNs is their fairly sluggish curing condition .…”

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.…”

Phthalonitrile Blends: Simple Way to Improve Physical Properties by Increasing Crosslinking Density

“…132 °C) as the amine curing additive, a homogeneous mixture of the resin and additive can be achieved at a much lower temperature than that seen in previous research using p ‐BAPS (M.P. 192 °C) . The DSC thermogram of formulation 3a containing m ‐BAPS revealed a glass transition temperature ( T g ) of ≈75 °C, assigned to the PN resins, followed by an exothermic transition starting at 225 °C and peaking at 275 °C, attributed to the reaction of the PN resin with m ‐BAPS .…”

“…Phthalonitrile (PN) resins, which exhibit many desirable traits, can be grouped into either the first‐generation PN resins or the oligomeric second‐generation PN systems. The first‐generation PN consists of small crystalline molecules synthesized from the diphenolate salts of bisphenols (e.g., 4,4′‐biphenol, bisphenol A, bisphenol AF, etc.)…”