MOLECULAR-TRANSPORT OF ALKANES THROUGH THERMOPLASTIC MISCIBLE BLENDS OF ETHYLENE-PROPYLENE RANDOM COPOLYMER AND ISOTACTIC POLYPROPYLENE

A new experimental protocol based on the measurements of sorption (S), desorption (D), resorption (RS), and redesorption (RD) has been used to study the molecular transport of aliphatic alkanes through the misc ible blends of an ethylene-propylene random copolymer and an isotactic polypropylene over the temperature interval 25-70 degrees C. Diffusio n and activation parameters are evaluated and their dependencies on so lvent size, shape, and nature are discussed. Estimated values of the m olar mass between chain entanglements, kinetic rate constants, and ove rshoot index parameters have been influenced by the polymer-solvent in teractions. The sorption-diffusion mechanism is found to be of anomalo us type. (C) 1995 John Wiley and Sons, Inc.