Multifunctional polybenzoxazine nanocomposites containing photoresponsive azobenzene units, catalytic carboxylic acid groups, and pyrene units capable of dispersing carbon nanotubes

Abstract

A new multifunctional benzoxazine monomer Azo-COOH-Py BZ includes an azobenzene unit, a carboxylic acid group, and a pyrene moiety.

Functional Silica and Carbon Nanocomposites Based on Polybenzoxazines

“…TGA analysis revealed that, without UV irradiation, the poly(dicoumarin Py BZ)/SWCNT (3 wt%) nanocomposite had a higher decomposition temperature and char yield than those of the coumarin‐containing PBZ, presumably because of the effect of the increased crosslinking density and nano‐reinforcement. We also prepared a trifunctional Azo‐COOH‐PyBz monomer through condensation of Azo‐COOH, 1‐aminopyrene (pyrene‐NH 2 ), and paraformaldehyde . Because Azo‐COOH‐PyBz contained a pyrene unit, it improved the dispersion of CNTs through π‐stacking; because of the presence of the carboxyl group and the catalytic effect of the SWCNTs, the maximum exothermic curing peak for the Azo‐COOH‐PyBz/SWCNT hybrid complexes shifted to lower temperature, compared with that of poly(Azo‐COOH‐PyBz), based on DSC thermograms.…”

“…We also prepared a trifunctional Azo-COOH-PyBz monomer through condensation of Azo-COOH, 1-aminopyrene (pyrene-NH 2 ), and paraformaldehyde. [94] Because Azo-COOH-PyBz contained a pyrene unit, it improved the dispersion of CNTs through π-stacking; because of the presence of the carboxyl group and the catalytic effect of the SWCNTs, the maximum exothermic curing peak for the Azo-COOH-PyBz/SWCNT hybrid complexes shifted to lower temperature, compared with that of poly(Azo-COOH-PyBz), based on DSC thermograms. TGA analysis was used to investigate the effect of SWCNTs and MWCNTs on the thermal stability of Azo-COOH-PyBz after thermal curing polymerization; it revealed that the char yield and value of T d of poly(Azo-COOH-PyBz) increased to greater degrees in the presence of SWCNTs than in the presence of MWCNTs, possibly because of the greater thermal conductivity of the SWCNTs within the PBZ matrix.…”

Synthesis and Application of Arylaminophosphazene as a Flame Retardant and Catalyst for the Polymerization of Benzoxazines

“…The high curing temperature of benzoxazines is one of the problems that limits their widespread application [ 23 ]. The main way to solve this problem is to use catalysts [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ] such as phenols [ 24 , 25 ], strong acids [ 26 ], carboxylic acids [ 27 , 28 ] and Lewis acids [ 29 , 30 , 31 , 32 , 33 ]. All listed compounds are effective catalysts for the homopolymerization of benzoxazines; however, due to their high catalytic efficiency, one cannot use them in a mixture with the most common reactive compounds, such as epoxy resins, since they cause earlier curing of epoxy oligomers, thereby complicating the polymerization of benzoxazine.…”

Coumarin- and Carboxyl-Functionalized Supramolecular Polybenzoxazines Form Miscible Blends with Polyvinylpyrrolidone

“…The physical characteristic of PBZs can be improved using three main approaches. First, through the addition of inorganic materials (e.g., clay [ 6 ], polyhedral oligomeric silsesquioxane (POSS) [ 7 , 8 ], carbon nanotubes [ 9 , 10 , 11 , 12 ], graphene [ 13 ]) to form PBZ nanocomposites. Second, through use of functionalized BZ monomers presenting, for example, allyl, vinyl, pyrene, nitrile, methacryloyl, benzoxazole, and carboxylic acid groups [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

“…Third, through blending with other thermal plastics or thermoset resins (e.g., poly( N -vinyl-2-pyrrolidone) (PVP), polyurethane, epoxy resin) [ 21 , 22 , 23 ]. As an example of the second approach, the Azo-COOH BZ monomer contains both azobenzene and COOH units, with the latter serving as a catalyst that lowers the curing temperature relative to that of traditional BZ monomers [ 11 ].…”