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

Abstract

Abstract. Binary blends composed of 1,3-bis (3,4-dicyanophenoxy) benzene (3BOCN) and ionic liquids (ILs) with different molecular structures were prepared. The curing behavior of these 3BOCN/ILs blends were studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and rheological analysis. The study suggested that the blends possessed a wide processing window and the structures of ILs (anion, cation and alkyl chain length at cation) had an effect on curing behavior. The 3BOCN/[EPy]BF 4 resins were prepared at elevated temperature. IR spectra of the resins showed that there were triazine and isoindoline formed in curing process. The TGA and dynamic mechanical analysis (DMA) revealed that the resins have excellent thermal stability together with high storage modulus and high glass transition temperature (T g ). Dielectric properties, long term oxidative aging and water uptake measurements of the resins suggested the IL brought some unique properties to the resins.

Understanding curing dynamics of arylacetylene and phthalonitrile thermoset blends

“…Co‐curing of PN systems with different types of cross‐linking agents has provided tuning of material properties of the resulting composites 24 . Curing PNs with ionic liquids can improve their dielectric and long‐term oxidative stabilities, likely due to the ability of these additives to induce a higher degree of cross‐linking within the thermosets 29 . Experiments that co‐cured PNs with tetrafluoroborate‐ and hexafluorophosphate ‐containing imidazolium‐ and pyridinium‐based ILs demonstrated that the addition of boron‐containing anions yielded much higher curing rates than phosphorus anion chemistries, while pyridinium were more effective than imidazolium cations at cross‐linking PNs 29 .…”

Investigation on curing reaction of phthalonitrile resin with nanosilica and the properties of their glass fiber‐reinforced composites

“…These high stable units contributed to phthalonitrile resin with outstanding thermal stabilities, high T g , good flame retardancy and high mechanical properties, which could be applied as advanced structural materials 20–22 . However, pure phthalocyanine also showed high melting points and slow curing reactions without curing agents 23 . In order to improve the problems of pure phthalonitrile resin, phthalonitrile containing benzoxazine (BA‐ph) was synthesized in our previous researches with low melting point, wide processing window and self‐catalysis properties 24 .…”

“…[20][21][22] However, pure phthalocyanine also showed high melting points and slow curing reactions without curing agents. 23 In order to improve the problems of pure phthalonitrile resin, phthalonitrile containing benzoxazine (BA-ph) was synthesized in our previous researches with low melting point, wide processing window and self-catalysis properties. 24 The properties like curing reactions, processing properties, thermal stabilities and their fiber reinforced composites were investigated.…”

Deep eutectic solvent for curing of phthalonitrile resin: Lower the curing temperature but improve the properties of thermosetting

“…Consequently, several curing agents, including ionic liquid and metal complexes, have been developed to reduce the curing temperature of phthalonitrile. [8][9][10][11][12] Laskoski et al 8 designed a new curing system with Cu(II) acetylacetonate/p-toluenesulfonic acid as the curing agent, where the curing temperature of the phthalonitrile resin was observed to reduce to around 150 C as compared to the traditional aromatic diamine curing agent. Nonetheless, the glass transition temperature (T g ) of the resin was 205 C only at a curing temperature of 300 C. Zhao et al 9 employed melamine as the curing agent.…”