Toughening of thermosetting composites with thermoplastic fibres

The use of thermoplastic fibres to provide an increase in toughness for laminates manufactured with brittle resins has been investigated. The thermoplastic fibres were dispersed into the preforms for the composite laminates, either by commingling with the structural fibres prior to fabric manufacture, or by inserting them in the form of veils in between the layers of structural fibres. In both cases the toughened laminates were shown to exhibit superior damage tolerance to the untoughened laminates manufactured with plain structural fibre reinforcement. Laminates produced using woven carbon fibres were found to exhibit dramatically increased modes-I and -II interlaminar toughness when commingled nylon fibres were used. Laminates manufactured with glass fibre and both PP and nylon commingled fibres exhibited superior impact resistance in terms of energy absorbed during penetration impacts, compared to plain glass fibre laminates. Laminates produced with a thermoplastic fibre that dissolved in the thermosetting matrix during cure did not exhibit any improvement in through penetration impact properties.