Catechol and epoxy functionalized ultrahigh molecular weight polyethylene (UHMWPE) fibers with improved surface activity and interfacial adhesion

In this work, a combination of bio-inspired poly(dopamine) deposition and epoxy grafting was proposed, aiming at improving the surface activity and adhesion property of ultrahigh molecular weight polyethylene (UHMWPE) fibers. Inspired by adhesive proteins in mussels, dopamine self-polymerization was used to deposit a thin adherent poly(dopamine) (PDA) film onto the surface of UHMWPE fibers. Ethylene glycol diglycidyl ether (EGDE) was then grafted through the reactions with amide and imino groups of poly(dopamine) surface via a “two-step” or “one-step” method. The chemical structure and composition of fiber surface were characterized by XPS and ATR-IR. The surface hydrophilicity and wettability was determined by water contact angle (CA) measurement. SEM images revealed the morphology changes of the fibers. TGA and gravimetric method were applied for quantitative analysis of the surface treatment of each step. Epoxy value of modified fibers was evaluated by the titration method. The results confirmed that PDA was deposited and EGDE was successfully grafted onto the surface of fibers. The interfacial adhesion properties of UHMWPE fibers/rubber composites were investigated by single-fiber pull-out test, and 67.5% improvement was achieved. Resorcinol–formaldehyde–latex (RFL) dipping further enhanced the improvement to 365.4%. Catechol and epoxy grafted UHMWPE fabrics after dipping with RFL exhibited excellent adhesion properties with satisfying aging and fatigue resistance.