SURFACE MODIFICATION OF POLY(TETRAFLUOROETHYLENE-CO-HEXAFLUOROPROPYLENE) - INTRODUCTION OF ALCOHOL FUNCTIONALITY

The reduction of poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) was studied with regard to the kinetics of reaction and the product structure. The thickness of the resulting modified surface layer (depth of reaction) can be controlled by using reaction time and temperature. At -78°C the thickness can be controlled in the range of 250-800 A. The air-sensitive reduction product contains carbon-carbon double and triple bonds, aliphatic C-H bonds, alcohols, carbonyls, and very little fluorine. The sources of the oxygen and C-H functionality were studied. Hydroboration followed by oxidation introduces alcohol functionality to the surfaces. The alcohols exhibit low reactivity in esterification reactions, but yields can be improved by using acylation catalysts; their reactivity is analogous to hindered alcohols in solution. Base-catalyzed addition of ethylene oxide renders surface-bound primary alcohols, increasing the reactivity of the surface toward esterification. Lower yields of primary alcohols can be directly introduced to the surface by reaction of the reduced layer with 9-BBN, followed by carbonylation and reduction. © 1990, American Chemical Society. All rights reserved.