Making Benzoxazines Greener: Design, Synthesis, and Polymerization of a Biobased Benzoxazine Fulfilling Two Principles of Green Chemistry

Abstract

Sesamol and furfurylamine are used to synthesize a novel benzoxazine monomer as part of the quest to develop greener benzoxazine monomers simultaneously fulfilling two Principles of Green Chemistry, the use of renewable feedstocks and safer solvents and auxiliaries. Respecting principle 5, the so-called preferred solvents (ethanol and ethyl acetate) are used in both the syntheses and purification processes. The chemical structure of the synthesized monomer is verified by proton and carbon nuclear magnetic resonance spectroscopy (1H and 13C NMR), 2D 1H–13C heteronuclear single quantum correlation (HSQC) spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). The polymerization behavior of the monomer and the thermal stability of fully polymerized polybenzoxazine are studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A thermally stable polymer has been obtained as shown by the 5% and 10% weight reduction temperature (T d5 and T d10) values of 374 and 419 °C, respectively, and a char yield of 64%, making this thermoset a promising candidate for fire-resistant applications.

Bio‐based benzoxazines based on sesamol: Synthesis and properties

“…The methylene protons (CH 2 ) of furfurylamine, connecting with the oxazine ring, also seen a peak at 3.8 ppm. The results were consistent with the research of María L.S . The furan ring showed resonances at 6.59, 6.41, and 7.61 ppm.…”

“…It is reported that sesamol is an inhibitor of lipid metabolism in living organisms . However, the use of seasamol in the synthesis of benzoxazine has not received much attention …”

Low melting point, high thermal stable branched benzoxazines resin derived from mixed-substituted phosphazene core

“…1,3-Benzoxazine, a monomer of newly developed thermosetting resins called polybenzoxazines (PBZ), can be synthesized conveniently from primary amine, formaldehyde, and phenol by one-pot Mannich condensation [1,2]. Due to the wide range of selectivity of raw materials, it provides benzoxazines with molecular design flexibility and can meet the practical requirement by designing different monomer structures [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. For example, the tetra-functional fluorene-based benzoxazine resin (t-BF-a-c) was synthesized, which exhibits an exothermal peak at 276°C, and displays good processability and wide process window(60°C) due to the incorporation of cardanol [21].…”

Synthesis and properties of a novel bio‐based benzoxazine resin with excellent low‐temperature curing ability

“…With the extreme consumption of fossil energy, energy crises and environmental problems have become an issue that cannot be avoided and must be addressed positively. Therefore, the use of renewable bio‐based compounds instead of traditional fossil‐based compounds to prepare polymer materials has attracted many researchers . Benzoxazine monomer is prepared through dehydration to a ring by a Mannich condensation reaction based on a phenol source, an amine source and a formaldehyde solution or paraformaldehyde.…”

“…Therefore, the use of renewable bio-based compounds instead of traditional fossil-based compounds to prepare polymer materials has attracted many researchers. [1][2][3][4][5][6][7][8] Benzoxazine monomer is prepared through dehydration to a ring by a Mannich condensation reaction based on a phenol source, an amine source and a formaldehyde solution or paraformaldehyde. Benzoxazine resin is a kind of phenolic resin; furthermore it has better heat resistance, dielectric properties, low surface energy, low water absorption and no release of small molecules during processing compared with traditional phenolic resin, in addition to zero shrinkage and structure design flexibility.…”