RADICAL CHLORINATION OF POLYETHYLENE FILM - CONTROL OF SURFACE SELECTIVITY

The heterogeneous (gas-solid) reaction of polyethylene film with chlorine gas has been studied with the objectives of controlling the thickness of the chlorinated layer (depth of chlorination) and the extent of chlorination (density of chlorine atoms on the polyethylene chain). A combination of X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (both transmission and attenuated total reflectance-ATR IR), and gravimetric techniques was used to study the reaction products. Control of chlorination depth and chlorine density was accomplished by varying the pressure Of Cl2 and the photointensity. Control was demonstrated by preparing four 'extreme" types of modified film sample: a shallow layer of lightly chlorinated chains (SL), a shallow layer of highly chlorinated chains (SH), a deep layer of lightly chlorinated chains (DL), and a deep layer of highly chlorinated chains (DH).