Measurement of void collapse during resin transfer moulding

This paper considers the dissolution of cylindrical voids trapped between fibres during the resin transfer moulding process. To study the behaviour of the tiny voids, a system is used which consists of a transparent mould loaded with a glass fibre reinforcement. The mould is placed under a microscope and a small area of the preform is monitored during the injection of a vinylester resin. The length of the voids decreases at a relatively fast rate and they disappear in the order of minutes due to diffusion. The experimental results are rationalized through a theory showing how certain parameters influence the rate of dissolution. The investigation shows the significance of degassing the resin before injection. This is especially important when low pressures are utilized during injection. (C) 1997 Elsevier Science Limited.