Material PropertiesDirect fluorination of UHMWPE fiber and preparation of fluorinated and non-fluorinated fiber composites with LDPE matrix

In this study, the surface of ultra-high-molecular-weight polyethylene (UHMWPE) fiber used as reinforcement in low-density polyethylene (LDPE)/UHMWPE fiber composites was modified by direct fluorination using elemental fluorine, (10% F2+90% He) mixture, at 25 °C. A polymer composite based on LDPE/UHMWPE fibers was prepared. We studied the influence of surface treatment of the fibers on properties of the composite. The fibers were first used as received, and then were used after fluorine (direct fluorination) treatment of their surface. Stress-strain behavior of the prepared samples was measured. Thermal properties and the trans-crystallization of the matrix over the fibers were observed. The crystallization of the matrix on the fiber surface was followed by scanning electron microscopy and by differential scanning calorimeter (DSC) analysis. The structure of the interface was then observed by X-ray diffraction. Surface energy was determined by contact angle measurement and it indicates that the wetting properties of the fluorinated fiber composites were improved.