High-performance, Command-degradable, Antibacterial Schiff Base Epoxy Thermosets: Synthesis and Properties

Two diepoxies containing two-benzene-rings-conjugated Schiff base when cured with an aromatic diamine result in high-performance thermosets combining excellent controlled degradability, stability and antibacterial property. Epoxy resins have been widely used in coatings, adhesives, composites, electronic packaging materials, etc., but they are arduous to recycle and have no antibacterial activity. In this paper, two-benzene-rings-conjugated Schiff base diepoxy monomers were synthesized and further cross-linked with 4,4-diaminodiphenylmethane. The chemical structures of the diepoxies as well as their thermosets were characterized in detail. The property investigation manifested that the thermosets owned far higher glass transition temperature of ~206 °C, tensile strength of ~122 MPa, tensile modulus of~ 2646 MPa than a commonly-used high-performance bisphenol A epoxy resin. Moreover, they possessed excellent acidity and temperature-controlled degradability, and superior stability toward common solvents, thermal treatment and hygrothermal aging. Furthermore, they presented excellent coating properties (including hardness, adhesion, and solvent resistance) and antibacterial properties with bactericidal capability of ~91%.