Mussel-inspired environmentally friendly dipping system for aramid fiber and its interfacial adhesive mechanism with rubber

To strengthen the interfacial adhesion between aramid fiber and rubber, inspired by mussel adhesion protein and mimicking adhesive molecule, a new environmentally friendly dipping system was developed. Specifically, water-soluble pyrogallic acid and polyethyleneimine are reacted to form a network structure, which is then mixed with rubber latex to prepare the dipping solution. We use blocked isocyanate and epoxy aqueous solution to activate the fiber, and then conduct the dipping treatment. The H pull-out force between modified aramid fiber and rubber reached 147 N, achieving the level of traditional resorcinol-formaldehyde-latex dipping system (154 N), while avoiding the utilization of harmful resorcinol and formaldehyde. In addition, we employed atomic force microscope for the first time to quantitatively characterize the modulus of the transition layer between the fiber and rubber. Results from this research provide new insights into the interfacial design of aramid fiber/rubber composites and will facilitate the development of aramid fiber/rubber composites.