High temperature resorcinol-based phthalonitrile polymer

Abstract. Phthalonitrile and benzoxazine have been considered as high-performance materials in the field of heterocyclic chemistry. The polymerization of phthalonitrile and benzoxazine accelerated by active phenolic hydroxyl has attracted wide interests. In this work, self-promoted polymerization behavior and processability of phthalonitrile containing benzoxazine (BA-ph) with bisphenol-A (BPA) were investigated. Results revealed that BA-ph/BPA exhibited representative doublestage curing behaviors corresponding to the ring-opening polymerization of benzoxazine rings and ring-formation polymerization of nitrile groups. Compared with that of BA-ph, processability of BA-ph/BPA was improved and could be tuned by varying BPA contents, processing temperature and time. Then BA-ph/BPA/glass fiber (GF) composite laminates were prepared. In comparison with that of BA-ph/GF laminates (542 MPa and 25.8 GPa), the flexural strength and modulus were up to 789 MPa and 23.6 GPa, respectively. Moreover, double T g s were observed at temperature around 200~300°C and 300~380°C, indicating microphase separation during the polymerization of oxazine rings and nitrile groups, confirmed by the scanning electron microscopic (SEM) images. Thermal stabilities demonstrated that all BA-ph/BPA/GF composites exhibited high T 10% up to 510°C. The systematic study of BA-ph/BPA system could enrich our knowledge on phthalonitrile-based resins in industrial applications, especially in the areas which require excellent mechanical properties and high temperature resistance.

Section: Dynamic Thermomechanical Analysis Of the Ba-ph/bpa/gf Composmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Effect of bisphenol-A on the structures and properties of phthalonitrile-based resin containing benzoxazine

Xu¹,

Jia²,

Liu³

2015

“…The phthalonitrile monomer 3BOCN was synthesized depending on a reported literature [13]. (Figure 1 3 , and samples for oxidative aging studies were approximately 1.5×1.5×1.5 mm 3 .…”

Section: Synthesis Of 1 3-bis (3 4-dicyanophenoxy) Benzene 3bocnmentioning

confidence: 99%

“…In order to address this problem, considerable research efforts have been expended on the development for the curing agent. To date, lots of Lewis acids/bases curing agent, such as metallic salts, strong organic acids, strong organic acids/amine salts and active hydrogen-containing heterocyclic structures have been developed and used [8][9][10][11][12][13][14][15][16][17]. In addition to the traditional Lewis acids/bases, our laboratory also reported the cooperative curing effect between phthalonitrile and methyl tetrahydrophthalic anhydride end-capped imide compound (MODA) [18,19].…”

Section: Introductionmentioning

confidence: 99%

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

Cheng¹,

Lv²,

Z.³

et al. 2017

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.

“…There has been increasing interest in phthalonitrile polymers [1][2][3][4][5][6][7], owing to their excellent thermal and thermo-oxidative stability, high char yield, good chemical inertness, abrasion resistance, and flame resistance. But, there are several challenges to overcome with regard the processing of these materials with higher melting temperature and high processing temperature.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of a novel bisphthalonitrile containing benzoxazine

Cao¹,

Chen²,

Wei³

et al. 2007

Abstract. The novel bisphthalonitrile containing benzoxazine (BPNBZ) has been synthesized using bisphenol-A, 4-aminophenoxylphthalonitrile and paraformaldehyde. The structure of the monomer was supported by FTIR spectroscopy, 1 H-NMR, and 13 C-NMR spectra, which have exhibited that the reactive benzoxazine ring and cyano groups exist in molecular structure of BPNBZ. The cure reaction of BPNBZ was monitored by the disappearance of the nitrile peak and the tri-substituted benzene ring that is attached with oxazine ring peak at 2231, 951 cm -1 . The thermal polymerization of the BPNBZ was studied by differential scanning calorimetry (DSC) and dynamic rheometer. It was shown that the bisphthalonitrile containing benzoxazine had completely cured with two-stage polymerization mechanisms according to oxazine ring-opening and phthalonitrile ring-forming. The thermal decomposition behaviors of the polymer were examined by thermogravimetry analysis (TGA) in nitrogen and in air. The materials achieve char yields above 73% under nitrogen at 800°C and above 78% under air at 600°C, which exhibited the cured resin has good thermal stability and thermo-oxidative stability.