Cellular thermoplastic fibre reinforced composite (CellFRC): A new class of lightweight material with high impact properties

In many high performance composite applications, specific properties could be more valuable than absolute ones and each reduction of density in composite structures could represent a fundamental goal. Cellular lightweight fibre reinforced composites (CellFRC) were prepared embedding gas bubbles of controlled size within a thermoplastic matrix reinforced with continuous fibres. A semicrystalline high performance polymer, poly(ethylene 2,6-naphthalate), and glass fibre fabrics were used for the preparation of both conventional and CellFRC structures. Pores were induced after the composite was first saturated with CO2 and then foamed by using an “in situ” foaming/shaping technology based on compression moulding with adjustable mould cavities. The presence of micro- or submicro-sized cells in the new CellFRC reduced the apparent density of the structure and led to significant improvements of its impact properties. Both structural and functional performances were further improved through the use of a platelet-like nanofiller (expanded graphite) dispersed into the matrix.