Mechanism of Self-Sizing of Paper

Abstract

Investigations on the self-sizing of a pure cellulose paper show that surfactant acts to prevent self-sizing by solubilizing fatty acid molecules and forming a physical barrier to chemical bond formation between cellulose and fatty acid molecules. The acceleration of self-sizing by alum has a mechanism similar to that of conventional rosin-alum sizing: the formation and polymerization of aluminum soaps on the fibre surface. It is suggested that the reaction between cellulose hydroxyl groups and aluminum soaps, as proposed in the literature, is not likely. Instead, material that is not solvent-extractable is either extensively polymerized or reacted with residual carboxyl groups on the fibre surface.