Devolatilization of the polymerization by-products and the impregnation solvent during Vacuum Assisted Resin Transfer Molding (VARTM) of the polyimide polymers is analyzed using a combined continuum hydrodynamics/chemical reaction one-dimensional model. The model which consists of seven coupled partial differential equations is solved using a finite element collocation method based on the method of lines. The results obtained reveal that the main process parameters which give rise to lower gas-phase contents in the VARTM-processed polymer matrix composites are the vacuum pressure and the tool-plate heating rate. Lower tool-plate heating rates are found to be beneficial since hey promote devolatilization of the impregnation solvent at lower temperatures at which the degree of polymerization and, hence, resin viscosity are low. (C) 2003 Kluwer Academic Publishers