Influence of preformed rubber particle size distribution on the structure and properties of prepreg systems

Model epoxy prepreg systems were modified using crosslinked preformed rubber particles that were segregated into different size distributions. Large differences in the structure of the unidirectional carbon fiber laminates were found with varying toughener particle size distributions. As the average particle size was decreased an absence of a distinguishable interlayer was observed and a more homogeneous structure was formed. This resulted in a significant difference in the fracture toughness of the laminates due to a change in the failure mechanism. In this study, it is shown that differences in the structure and properties of interlayer toughened prepreg composites result from changing only the preformed rubber particle size distribution in the interlayer.