Polyamine-Diazirine Conjugates for Use as Primers in UHMWPE-Epoxy Composite Materials

Ultra-high-molecular weight polyethylene (UHMWPE) fibers show promise for use in fiber-reinforced polymer composites but have poor interfacial adhesion to the epoxy resin that would serve as the polymer matrix. Here, we describe the development of a diazirine-grafted polyamine that can be used as a topically applied primer for UHMWPE fibers. Activation of the diazirine groups on the primer initiates C-H bond insertion on the polyethylene fiber, leading to strong covalent bonds between the fiber and the polyamine coating. The covalently functionalized surface can then engage in nucleophilic addition reactions with epoxy resin-resulting in increased bonding to the epoxy matrix (demonstrated through lap-shear experiments) and increased performance for fiber-reinforced composite materials (demonstrated through lamination rates and short-beam stress measurements).