Internal Reflectance Spectroscopy of Reacted Surfaces: Fluorinated Polyethylene and Polypropylene

Abstract

The measurement of the depth of reaction of F₂ into the surface of polyethylene and polypropylene is reported. The roughness of the reacted surface has required the development of a novel three-layer, coated sample and subsequent theoretical analysis and analytical techniques. The results with polypropylene can be confirmed by visible reflectance fringes; however, in polyethylene the three-layer method is, at present, the only easy way to measure the extent of fluorine modification of the polymer surface. The extent of fluorination was found to be proportional to the time of exposure to F₂ gas and to increase with elevation of the sample temperature.