KINETIC ASPECTS OF WATER SORPTION IN POLYESTER-RESIN GLASS-FIBER COMPOSITES/

Solubility and diffusivity of wafer in sheet-moulding compound (SMC) m aterials based on polyester-resin/glass-fibre composites with variable content of fibres, filler (CaCO3) and other low-molecular-weight addi tives have been studied The main scope is the finding of a realistic a pproach to describing water sorption behaviour as a function of the hy drophilic character of the matrix, the mechanical properties of the ma terial and the water solubility of fibres, fillers and low-molecular-w eight compounds (solutes). The model previously proposed for simultane ous water sorption in and solute release from moderately hydrophobic m aterials has been generalised here in order to take into account exper imental findings on chemical and physical processes induced by water p enetration into the composites A method is developed that is based on the use of thermodynamic and kinetic parameters of water sorption/deso rption for the physico-chemical characterisation of SMC materials. (C) 1997 Published by Elsevier Science Limited.