IMPROVED TOUGHNESS AND FATIGUE PERFORMANCE OF CARBON FIBER COMPOSITES FROM NANOSILICA MODIFIED FIBER SIZING.

Carbon-fiber composites are increasingly being considered to replace metals in both aerospace and automotive applications due to the relative weight savings they offer. In order to qualify for such demanding applications, composite materials are subject to meet the requirements of damage tolerance and durability. However, thermoset resins based carbon fiber composites are typically not at par with metals in these properties, measured as toughness and fatigue resistance. Solutions to improve such properties do exist and are used in aerospace parts, but they come at high loading levels of resin modifiers and significant additional cost, which makes them infeasible for high volume applications. Nanosilica based resin modifiers have been shown to improve toughness and fatigue properties in carbon fiber composites, when used to modify the epoxy resin used in its matrix. In this paper, we demonstrate that the toughness and fatigue performance of both glass and carbon fiber composites can be improved when nanosilica is used at less than 1% loading to modify the fiber sizing. This approach offers a cost-efficient method to improve the toughness and fatigue performance of composites for lightweight transportation applications, without any additional processing or cycle times. [ABSTRACT FROM AUTHOR]