A comparison of physical properties of glass fibre epoxy composites produced by wet lay-up with autoclave consolidation and resin transfer moulding

Comparisons are reported for composite samples of similar resin and fibre systems which were processed using the wet lay-up with autoclave consolidation and resin transfer moulding (RTM) by vacuum impregnation. Similar degrees of cure were obtained for laminates using the two methods of processing and the arising thermal and physical properties (tensile, flexural, interlaminar shear strength (ILSS), void content and thickness variation) were measured. The fibre dominated properties (i.e. flexural and tensile strength) were found to be higher for the autoclaved samples due to the higher volume fraction arising from the superior compaction pressure, although when normalised on the basis of fibre volume fraction the results were similar. The matrix dominated ILSS values were higher for the RTM samples and this was attributed to improved wetting, reduced void content and a slightly lower degree of cure. Thermal analysis also indicated that the autoclaved (60% glass fibre by volume) composite attained a slightly higher glass transition temperature than that achieved by RTM (50% fibre by volume) for similar cure times and cure temperatures. The significance of the results in an industrial context is discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.