Vinyl Acetate → Vinyl Acetate

This Example shows the preparation of high TFE content copolymer. The conditions of Example III were repeated except that a total of 470 mg of APS was added, the TFE addition rate was 0.01 lb/min (4.5 g/min), the vinyl acetate addition rate was 2 ml/min., and the final agitation rate was 80 rpm. 2580 g of a 25.0 wt % solids colloidal dispersion was obtained. To 100 g of the isolated, dried polymer was added 500 ml of methanol and 40 ml of concentrated ammonium hydroxide. After several weeks at room temperature with occasional shaking, the resulting solution was heated to remove the reaction by-products and there was obtained a hazy, viscous solution of 19 wt % solids of approximate composition 82 wt % TFE, 16 wt % vinyl alcohol, and 2 wt % vinyl acetate. Upon evaporation of the solvent at 50° C. in a vacuum oven for one day, a clear, somewhat rubbery melt fabricable polymer was obtained.