Tunable Adhesion Properties of UHMW-PE Fiber/Matrix Interface Using Plasma Surface Treatments

Fiber-reinforced polymer composites are ubiquitous materials used to impart toughening or energy absorbing properties. The performance of these materials is highly dependent upon the micromechanical response at the fiber/matrix interface. A major limitation on the overall performance of fiber-reinforced composites is the adhesion failure at the fiber/matrix interface. Efforts has been focused on enhancing the adhesion at the interface by means of chemical bonding through the introduction of reactive groups on the surface of the fibers where the adhesional strength have show significant improvements. These reactive groups mainly consist of hydroxyl, carboxylic, and amine groups.

We report the use of atmospheric pressure non-thermal plasma surface treatments to functionalize the surfaces of ultra high molecular weight polyethylene (UHMW-PE) fibers along with the effects of the treatments on the micromechanical behavior at the fiber/matrix interface. Different plasma treatment conditions were implemented and a micromechanical test model, the microdroplet test was used to quantify the shear strength and total energy absorption. X-ray photoelectron spectroscopy (XPS) coupled with conventional titration methods were used to complement the results obtained from the microdroplet test and to quantify the surface concentration of the reactive groups. Doing so will provide an insightful understanding towards achieving tunable interfacial properties based on optimized surface treatment conditions to selectively create specific functional groups on the surfaces of the fibers.