Preparation of Organic Solvent-Soluble Proteins and Their Application: Solute Permeabilities and Dyeing Properties of Polyacrylonitrile/Modified Protein Composite Membranes

Abstract

To understand the structure of composite membranes prepared from polyacrylonitrile (PAN) and modified milk whey (MMW) or egg white (MEW), obtained by reacting with 2,4-tolylen diisocyanate, we have investigated the membrane potential, solute perme ability, and dyestuff adsorption. The membrane potential measurements confirm that at least some parts of modified protein components in composite membranes with high modified protein contents are incorporated by passing through the membranes. Solute permeability, equilibrium adsorption, and the adsorption rate of some dyestuffs through/on the composite membranes increase with increased modified protein content in the membrane. The properties of MMW/PAN and MEW/PAN are quite different because their characteristic structures are different: the shape of "island" MMW in "sea" PAN is elliptical, and that of "island" MEW is flat and oriented parallel to the membrane. Furthermore, equilibrium Methylene Blue (MB) adsorption on the composite mem branes indicates that there are some interactions between PAN and MMW up to a ratio of about 6.5 g (MMW)/100 g (PAN), and the interacted MMW parts have no affinity for MB.