Bioinspired Design Provides High‐Strength Benzoxazine Structural Adhesives

Abstract

A synthetic strategy to incorporate catechol functional groups into benzoxazine thermoset monomers was developed, leading to a family of bioinspired small‐molecule resins and main‐chain polybenzoxazines derived from biologically available phenols. Lap‐shear adhesive testing revealed a polybenzoxazine derivative with greater than 5 times improved shear strength on aluminum substrates compared to a widely studied commercial benzoxazine resin. Derivative synthesis identified the catechol moiety as an important design feature in the adhesive performance and curing behavior of this bioinspired thermoset. Favorable mechanical properties comparable to commercial resin were maintained, and glass transition temperature and char yield under nitrogen were improved. Blending of monomers with bioinspired main‐chain polybenzoxazine derivatives provided formulations with enhanced shear adhesive strengths up to 16 MPa, while alloying with commercial core–shell particle‐toughened epoxy resins led to shear strengths exceeding 20 MPa. These results highlight the utility of bioinspired design and the use of biomolecules in the preparation of high‐performance thermoset resins and adhesives with potential utility in transportation and aerospace industries and applications in advanced composites synthesis.

Catechol‐Based Molecular Memory Film for Redox Linked Bioelectronics

“…From a bioelectronics perspective, the memory can respond to biologically relevant redox contexts and engage biological redox-activities (e.g., enzyme-catalyzed redox reactions) through thermodynamically controlled electron transfer reactions. Overall, this work further extends the functional possibilities of catecholbased materials that are of increasing interest in biology (e.g., melanin [40][41][42][43][44][45][46][47] ) and technology (e.g., polydopamine [48][49][50][51] ).…”

Biobased Bisbenzoxazine Resins Derived from Natural Renewable Monophenols and Diamine: Synthesis and Property Investigations

“…Utilizing naturally sourced chemicals to synthesize biobased polymers has been more and more important in order to satisfy the demand of sustainable development. − Replacing petroleum-derived raw materials by natural sustainable sources for synthesizing novel benzoxazines is also attracting great interests from both industry and academia . Recently, bio-benzoxazine resins based on various sustainable phenols such as catechol, urushiol, cardanol, magnolol, guaiacol, daidzein, resveratrol, , coumarin, − and ferulic acid are extensively investigated in benzoxazine resin filed. However, bio-benzoxazine resins based on renewable amines have rarely been reported.…”

Chrysin-Based Bio-Benzoxazine: A Copolymerizable Green Additive for Lowering Curing Temperatures and Improving Thermal Properties of Various Thermosetting Resins

“…In order to scale up the resin synthesis, such a synthesis approach with complex reaction steps is not acceptable due to the high cost and environmental issues. Hence, it is meaningful to develop a simple synthesis method to achieve phenolic hydroxyl-containing benzoxazines . Chrysin contains two phenolic hydroxyl groups, and one of which is expected to be bonded in an intramolecular six-membered ring.…”

“…Hence, it is meaningful to develop a simple synthesis method to achieve phenolic hydroxyl-containing benzoxazines. 51 Chrysin contains two phenolic hydroxyl groups, and one of which is expected to be bonded in an intramolecular sixmembered ring. Therefore, we hypothesized that only one phenolic hydroxyl group in chrysin shows the reactivity to form oxazine ring in the Mannich condensation.…”