Interfacial Shear Strength Studies of Plasma-Treated Ultra-High Molecular Weight Polyethylene Fibers

One particular aspect of research surrounding fiber reinforced polymer composites has been the engineering of the interphase that exists between the fiber and polymer matrix. Surface treatment of fibers is a commonly used route to improve the adhesion of the fibers to the polymer matrix. Based on prior work, atmospheric plasma treatments have shown to successfully functionalize the surfaces of ultra-high molecular weight polyethylene (UHMW-PE) fibers with polar groups such as hydroxyl, carboxylic, and amines groups. These functional groups serve as reactive sites where covalent bonds can form between the fibers and polymer matrix to improve upon the interfacial strength. In this investigation, different plasmas – N2, O2, and N2+H2 gases and various treatment conditions were utilized to surface treat UHMW-PE fibers. The interfacial shear strength (IFSS) of these plasma-treated fibers was assessed using a single-fiber Microdroplet shear test. X-ray Photoelectron Spectroscopy (XPS) was used to correlate the interfacial strength to the type of chemical functional group.