Unexpected Healability of an ortho-Blocked Polybenzoxazine Resin

Abstract

Ring-opening polymerization of bifunctional benzoxazine has long been thought to produce a permanent network structure without reprocessing ability. Here, we demonstrate that surprising healability can be achieved by a controlled polymerization of an ortho-blocked bifunctional benzoxazine poly(oC-hda). The cured resin possesses a crosslinked structure, but can be deformed, remolded from crushed pieces or healed from mechanical damage. Based on a series of intensive experiments, we show that the healability can be explained by a dynamic bonding exchange mechanism between the phenoxy structures existing during the curing process. Moreover, we verify the possibility to heal the fatigue damaged poly(oC-hda) based composite to extend its service life. Our study provides another dynamic covalent bond to synthesize healable polymers, offering a broad platform for combining healability and desired thermosetting features together.

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].…”

The Journey of Phenolics from the First Spark to Advanced Materials

“…Robust mechanical performance, especially high T g values, low flammability, high hydophobicity, rich hydrogen bondings etc . were obtained using phenolphthalein, aromatic ketone, imide, amide, and nitrile group containing phenols or amines . Likewise, benzoxazines from renewable reagents were synthesized, successfully .…”

“…were obtained using phenolphthalein, aromatic ketone, imide, amide, and nitrile group containing phenols or amines. [83][84][85][86][87][88][89][90] Likewise, benzoxazines from renewable reagents were synthesized, successfully. [91,92] It should be mentioned that naphthols can be used to replace phenols and several naphthoxazines were also synthesized accordingly.…”

Bio‐basedbenzoxazine from renewableL‐tyrosine: Synthesis, polymerization, and properties

“…As a result, developing bio‐based polymers from renewable resources are rapidly evolving 1–6 . Polybenzoxazine is a promising thermoset due to its outstanding comprehensive performance such as excellent thermomechanical properties, inherent low flammability, low surface free energy, low dielectric constants, and near‐zero shrinkage upon curing 7–14 . However, the commercial benzoxazines are mainly derived from petroleum.…”

“…[1][2][3][4][5][6] Polybenzoxazine is a promising thermoset due to its outstanding comprehensive performance such as excellent thermomechanical properties, inherent low flammability, low surface free energy, low dielectric constants, and near-zero shrinkage upon curing. [7][8][9][10][11][12][13][14] However, the commercial benzoxazines are mainly derived from petroleum. Considering the great flexibility of molecular design, various bio-based phenols and primary amines have been directly applied to prepare benzoxazines.…”