Surface modification of polymers by direct fluorination: A convenient approach to improve commercial properties of polymeric articles

Abstract

The fundamental features and industrial applications of the direct fluorination of polymers are reviewed. Direct fluorination of polymers (i.e., treatment of a polymer surface with gaseous fluorine mixtures) proceeds spontaneously at room temperature and is a surface modification process. More than 25 polymers have been studied with the aid of a variety of analytical and spectroscopic techniques. The fundamental features of the direct fluorination, such as influence of treatment conditions (composition of the fluorinating mixture, fluorine partial pressure, temperature, and fluorination duration) on the rate of formation, chemical composition, density, refraction index, and surface energy of the fluorinated layer, kinetics of formation of radicals during fluorination and their termination, texture of fluorinated layer, etc. were studied. It was demonstrated experimentally that direct fluorination can be effectively used to enhance commercial properties of polymer articles, such as barrier properties of polymer vessels, bottles, and packaging films and envelopes; gas-separation properties of polymer membranes; adhesion and printability properties of polymer articles; and mechanical properties of polymer-based composites.

Fluorine gas treatment improves surface degradation inhibiting property of alumina-filled epoxy composite

“…Among them, the direct fluorination has shown preferable results in a wide range of industry application because it can tailor the surface property of dielectric materials without compromising the bulk performance. [11][12][13] By controlling treatment factors during the direct fluorination process, a surface layer containing C-F bonds with preferable surface properties can be obtained. 14,15 In An's research, by controlling direct fluorination time and temperature, different surface conductivities are obtained in epoxy resins.…”

Suppression of surface charge accumulation on Al2O3-filled epoxy resin insulator under dc voltage by direct fluorination

“…14,15 Fluorination has been well developed from fundamental concepts to industrial applications for almost forty years and it is interesting to note that, via fluorination, excellent surface properties similar to those of fluoropolymers can be achieved without compromising the bulk characteristics of the original insulation. 16,17 The previous work focused on the surface potential decay phenomenon of the unfilled pure epoxy resin samples after corona charging. 18 In this paper, a downsized GIL disc insulator made of Al 2 O 3 -filled epoxy resin is fluorinated for investigation for the first time, of which the material and casting process are the same as industrial application.…”

Surface fluorinated epoxy resin for high voltage DC application

“…Through direct-fluorination treatment, the 'light' hydrogen atoms are replaced with 'heavier' fluorine atoms, so the density of the treated surface-fluorinated epoxy resins should be greater as compared with the density of the original materials [108]. In order to reduce the possibility of defect formations in the polymer during the fluorination treatment, namely the chain scissions, macro-and micro-defects, as well as caverns, a "mild" treatment condition is adopted at the industrial level, as well as in this research.…”