Novel epoxy-benzoxazine water-based emulsions with reactive benzoxazine surfactants for coatings

Abstract

Abstract. Novel epoxy-benzoxazine emulsions designed for water-based coatings were prepared and investigated. Bisphenol#A-based epoxy resins with molar weights of 340, 377 and 1750 g/mol along with epoxidized soybean oil were emulsified using mono-and bi-functional benzoxazine surfactants, which are able to react with epoxy resins at their cure temperature. The structure of synthesized surfactants carrying one or two polyether chains was confirmed using Fourier transform infrared spectroscopy, 1 H nuclear magnetic resonance and differential scanning calorimetry. Stability of emulsions was verified by particle diameters measurements. Coatings, made directly from emulsions, were dried and cured at elevated temperature using 3,3$-dimetoxybenzidine as curing agent to ensure a highly cross-linked structure of thermosetting films. Curing process, thermal properties and hardness of cured films were investigated. It was found that benzoxazine molecules were well incorporated into the epoxy network upon curing, which ensures no void structure of cured copolymer and enhanced coating properties.

Thermally Assisted Self‐Healing and Shape Memory Behavior of Diphenolic Acid‐Based Benzoxazines

“…A synthesis of two benzoxazine precursors (DaSa‐BOX and DaJa‐BOX) was performed by Mannich‐type polycondensation reaction ( Figure ) according to our previous reported procedures. [ 37–39 ] Great flexibility in (poly)benzoxazine molecular design and its unique chemical structure should meet specific requirements needed for self‐healing and/or shape memory applications. For instance, extensive intramolecular and intermolecular hydrogen bonding, typically present in polybenzoxazine molecule, assists repetitive supramolecular attractions, and so repair of polymer material.…”

Polybenzoxazine/carbon nanotube nanocomposites as a polymeric sensing material for volatile organic compounds

“…The easy processability of benzoxazine can explain development of benzoxazine chemistry. Benzoxazine have the simple preparation method of amine, phenol, and formaldehyde in one pot [15][16][17][18][19][20]. PBZ also has characteristics that are unusual for many resins, such as low water adsorption, which appears to contradict the phenolic nature of the resin, and limited or no shrinkage upon curing [21][22][23].…”

Study on an amine-containing benzoxazine: Homo- and copolymerization with epoxy resin

“…The related mechanism was later clarified by Sun et al [16], who purposed that the promotion effect is based on the basicity of amines. Moreover, Ambrožič et al [17] used o-dianisidine to prepare novel Ep-Bz emulsions for water-based coatings to ensure a highly cross-linked structure. Meanwhile, Zhao et al [18] and Wang et al [19] studied a Bz/Ep/imidazole ternary system, through which the curing steps were optimized to motivate reaction-induced phase separation so that toughness can be enhanced.…”