Resin transfer moulding (RTM) is commonly used for the production of high-performance fibre-reinforced polymer composites. In numerous application areas, the addition of fillers is necessary to enhance some properties of the polymer matrix or provide it with additional properties, such as flame retardancy. As many of the applied additives are solid phase, the reinforcement layers may filter the solid phase additive particles during RTM, resulting in a non-uniform distribution and uneven performance. Consequently, the proper distribution of the solid phase additives in composites is of key importance. This review primarily aims at facilitating the production of flame retarded structural composites by RTM in cases where the required fire performance can only be achieved with solid additives. First, the parameters influencing the particle distribution, along with the models describing it, are reviewed. Then, analytical methods for determining the particle distribution in composites manufactured by RTM are presented. Finally, the possible solutions to improve the particle distribution of solid phase additives are outlined.
Keywords: fibre-reinforced composite; flame retardant; particle distribution; resin transfer moulding; solid phase additive.