WATER TRANSPORT IN A POLYKETONE TERPOLYMER

Water transport in a polyketone terpolymer was analyzed performing bot h sorption and permeation experiments. Water vapor sorption tests were conducted at four temperatures (35, 45, 55, and 65 degrees C) and at several activities. The analysis of sorption isotherms revealed the oc currence of water clustering. A reduction of the endothermicity of mix ing as the amount of sorbed water increased was observed which is cons istent with significant association of penetrant molecules in the poly mer. Permeation experiments performed at 35 degrees C at upstream pres sures ranging from 4 to 25 Torr showed evidence of a reduction in wate r diffusivity as function of sorbed water concentration which is a typ ical indication of penetrant aggregation. (C) 1995 John Wiley and Sons , Inc.