Active diluents effects of 4-nonylphenoxy-1, 2-dinitrilbenzene on phthalonitrile containing benzoxazine and their copolymerization behaviors

Abstract

4-nonylphenoxy-1, 2-dinitrilbenzene (NP-ph), a novel kind of phthalonitrile containing flexible hydrocarbyl chains, has been synthesized. The structures of NP-ph were investigated by Nuclear Magnetic Resonance Spectroscopy (1H-NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Low viscosity NP-ph/phthalonitrile containing benzoxazine (BA-ph) blends were achieved by melt blending BA-ph with various content of NP-ph. Copolymerization behaviors and processability of NP-ph/BA-ph have been investigated by Differential Scanning Calorimetry (DSC) and Dynamic Rheological Analysis. Results indicated that NP-ph/BA-ph blends processability was improved and can be controlled by varying NP-ph contents, processing temperature and time. NP-ph/BA-ph polymers were prepared from the thermal polymerization with short curing time and low curing temperatures without addition of any other curing agents, which displayed high glass transition temperature (>360°C) and attractive thermal decomposition temperature (>420°C). The outstanding glass transition temperature and desirable thermo-oxidative stabilities, together with good processability and sound process conditions could enable the NP-ph/BA-ph polymers to be further explored in the fields under some practical critical circumstances with requirements of high wears and temperatures

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

“…Moreover, the absorption intensity of nitrile groups decreased with increasing the content of BPA, suggesting the obvious catalysis. The wide and intensive absorption band at around 3364 cm -1 corresponding to the association state of hydroxyl were observed in all of the samples, reported previously [15,16]. The absorption peak at 2969 cm-1 was assigned to the stretching vibration of -CH 3 and no obvious changes were observed.…”

“…On the one hand, the active phenolic hydroxyls generated from ring-opening of benzoxazine can be used as a kind of curing agent to achieve the cross-linking networks, thus realizing the self-promoted copolymerization. On the other hand, the active phenolic hydroxyls allowed BA-ph to be used as hydroxyl-functional phthalonitrile to achieve good processability and desirable properties of the composites [14][15][16]. In addition, the initial curing temperature and postcuring temperature of BA-ph were 200~220 and 280°C, respectively, which significantly improved the processibility of phthalonitrile-based resins.…”

“…The reason was that the ring-opening reaction reinforced by BPA monomer and the formation of the Mannich bridge structures via ringopening polymerization was the first priority [11,14,16]. The second exothermic peak corresponded to the polymerization of nitrile groups catalyzed by the extra hydrogen provided from the ring-opening of oxazine rings and BPA.…”

“…For thermosetting resin, long time curing and elevated temperature treatment were necessary. In the previous work, BA-ph/GF systems were treated for 11 h and the temperature was up to 280°C [15,16]. Phthalocyanine/GF systems were generally treated at 320°C for 2 or 4 h to obtain the laminates with good properties.…”

Synthesis, curing kinetics and thermal properties of a novel self-promoted fluorene-based bisphthalonitrile monomer

“…In inert atmospheres, the main degradation step is observed which starts around 350 C and reaches its maximum around 560 C. However, the thermal degradation in air is observed around 650 C, which can be obviously distinguished from the character of degradation in N 2 . In addition, a further thermal chain scission can also appeared at elevated temperatures [46], which are associated with the different degradation mechanisms corresponding to thermal stability and thermal-oxidative stability.…”