Mussel‐mimetic, bioadhesive polymers from plant‐derived materials

Abstract Aim Mussel‐mimetic, bioadhesive polymers are synthesized from plant‐derived sources. The strong adhesive action is caused by interactions between the catechol groups at the end of the polymer terminal chains and the substrate surface. Here, we present a preliminary study of the adhesion properties and a discussion of the adhesion mechanism. Methods Two bioadhesive polymers were synthesized from natural plant‐derived monomers by the transesterification of: (a) caffeic acid (3,4‐dihydroxycinnamic acid; DHCA ) and p ‐coumaric acid (4‐hydroxycinnamic acid; 4 HCA ) to produce poly( DHCA ‐ co ‐4 HCA ); and (b) 4‐dihydroxyhydrocinnamic acid ( DHHCA ) and 3‐(3‐hydroxyphenyl) propionic acid (3 HPPA ) to produce poly( DHHCA ‐ co ‐3 HPPA ). Thermoplastic poly( DHCA ‐ co ‐4 HCA ) or poly( DHHCA ‐ co ‐3 HPPA ) was placed between glass, carbon, steel, or bovine dentin substrates, and a lap shear adhesion test was conducted to compare them using conventional cyanoacrylate glue and epoxy resin. Results The greatest adhesion for all tested substrates was exhibited by poly( DHHCA ‐ co ‐3 HPPA ), followed by epoxy resin adhesive, poly( DHCA ‐ co ‐4 HCA ), and cyanoacrylate adhesive. The adhesive strength of poly( DHHCA ‐ co ‐3 HPPA ) was greater than 25.6 MP a for glass, 29.6 MP a for carbon, 15.7 MP a for steel, and 16.3 MPA for bovine dentin. Conclusion The adhesion of poly( DHHCA ‐ co ‐3 HPPA ) might be the strongest reported for a mussel‐mimic adhesive system, and could be a feasible alternative to petroleum adhesives.