Understanding the curing behaviors and properties of phthalonitrile containing benzoxazine with a new type of aniline curing agent

Promoted polymerization of Phthalonitrile containing benzoxazine (BA-ph) was designed on basis of the catalysis performance of a type of aniline curing agent (2,6-bis(4-aminophenoxy)benzonitrile (BAB)). The curing processes and curing behaviors of BA-ph with BAB were investigated by differential scanning calorimetry (DSC) and gelatin time. With the assistance of orthogonal test analysis method, main factors that affected the prepolymerization of BA-ph were studied and the appropriate pre-polymerization conditions were determined. According to the results of dynamic rheological analysis (DRA) and Fourier transform infrared spectroscopy (FTIR), possible curing mechanism of BA-ph with BAB were proposed. The results show that BAB could reduce the prepolymerization temperature of BA-ph resin, and increase its polymerization rate and crosslinking degree, and the BA-ph/BAB polymer mainly formed the aromatic heterocyclic structure of triazine rings, phthalocyanine rings and polyisoindoline rings. Then, thermal stability of BA-ph (BAB15%) polymers pretreated at different temperatures and prepared at 200 degrees C was analyzed to understand the cross-linked structures. Results indicated that BA-ph (BAB15%) polymers exhibit outstanding thermal properties (T-5(%)>410 degrees C and integral program decomposition temperature (IPDT) reached 3342 degrees C). Mechanical properties and thermomechanical properties of glass fiber reinforced BA-ph composites were also investigated and exhibited excellent mechanical properties, to further reveal the effects of BAB on the polymerization of BA-ph resin and expand the application of high-performance resin-based composites.

Automated summary

A promoted polymerization method for a phthalonitrile-based polymer was designed and its curing processes and behaviors were investigated. The results showed that this method could reduce the prepolymerization temperature, increase the polymerization rate and crosslinking degree, and form specific aromatic heterocyclic structures. The polymer exhibited outstanding thermal and mechanical properties.