Design of thermosetting polymeric systems based on benzoxazines modified with maleic anhydride

Abstract

A novel benzoxazine (BzPFA) with carboxylic acid groups in its structure was synthesized in a two-step process. First, BzPOH monomer was obtained from bisphenol A, paraformaldehyde, and ethanolamine with an initial molar ratio 1:4:2. Then, BzPOH was reacted with maleic anhydride using a stoichiometric 1:1 ratio of oxazine ring:maleic anhydride to produce a mixture of oligomeric species named BzPFA. The products were characterized by nuclear magnetic resonance, size-exclusion chromatography, and Fourier transform infrared spectroscopy. BzPFA presented a weight-average molecular weight of 50,000 g mol 21 . Mixtures of the novel precursor and the conventional benzoxazine based on bisphenol A (BzBA) (60:40 and 40:60 weight ratios) were prepared and three different curing conditions were considered in order to study the effect of BzPFA on curing and final properties. Blends exhibited improved properties respect to BzBA even at relatively low curing temperatures. These results can be associated to the network crosslinked by ester bonds that promotes a high rigidity.

Tuning morphology of siloxane bond‐based polybenzoxazines by controlling the sol–gel and curing processes

“…[ 1–5 ] Polybenzoxazine precursors are synthesized via one stage Mannich‐like condensation from a phenol derivative, formaldehyde, and a primary amine in a stoichiometric molar ratio of 1:2:1. [ 6–9 ] As benzoxazine chemistry offers high molecular design flexibility, some reactive functional groups have been incorporated into the molecular structure in order to afford materials with targeted properties. Aeronautical, electronic, and aerospace industries have focused on the use of these polymers as matrix systems due to their remarkable characteristics, such as: good thermal stability, high T g , long‐term dimensional stability, long‐term strength, low flammability, among others.…”

“…Aeronautical, electronic, and aerospace industries have focused on the use of these polymers as matrix systems due to their remarkable characteristics, such as: good thermal stability, high T g , long‐term dimensional stability, long‐term strength, low flammability, among others. [ 9–18 ] In particular, siloxane‐based polybenzoxazines have gained prominence due to their excellent thermal resistance and significant compatibility with organic compounds. [ 13,19–23 ]…”

Synthesis and characterization of polybenzoxazine/silica‐based hybrid nanostructures for flame retardancy applications

“…[21] Among the numerous benzoxazines developed, those derived from bisphenol A are the most investigated. [22][23][24][25][26] In this sense, functional groups such as phosphates, phosphine oxides, and silicon have been incorporated into their chemical structures in order to increase the fire performance of the final materials. [27][28][29][30][31][32][33][34][35] According to previous studies it could be concluded that the most effective systems to improve flame retardant properties are those based on phosphorous.…”

Bio‐based benzoxazines based on sesamol: Synthesis and properties

“…Although benzoxazine resin has various advantages as described above, it needs to be modified to broaden its range of applications. There are two main strategies for modification of benzoxazines: (1) selection of different phenolics and amines to alter the performance of benzoxazine resin and (2) preparation of composite materials by blending or copolymerizing with other materials …”

“…There are two main strategies for modification of benzoxazines: (1) selection of different phenolics and amines to alter the performance of benzoxazine resin and (2) preparation of composite materials by blending or copolymerizing with other materials. [19][20][21][22][23][24][25][26] However, most of the raw materials used for the synthesis of benzoxazine are derived from petroleum resources. To protect the environment and mitigate the depletion of petroleum resources, the use of renewable resources has become an important topic in various fields.…”