Effect of graphene nanoplatelets and carbon nanotubes in peek and peek/carbon fibre composites

  1. Angel Alvaredo Atienza
Supervised by:
  1. Roberto Guzmán de Villoria Director
  2. Juan Pedro Fernández Blázquez Director

Defence university: Universidad Carlos III de Madrid

Year of defence: 2019

  1. Juan Carlos Cabanelas Valcárcel Chair
  2. Alvaro Ridruejo Secretary
  3. Horacio J. Salavagione Committee member

Type: Thesis

Teseo: 590086 DIALNET


Recently, some industries such as aeronautic, automobile or electronic require a new generation of polymeric matrix composite materials with new properties and functionalities. For example, high electrical and thermal conductivity, which keep their mechanical properties, thereby enabling use in structural applications. Another important aspect is the recyclability at the end of material life. An example of the new generation of polymeric matrix composite materials is the multiscale and multifunctional materials using a thermoplastic matrix in which the properties of the polymer matrix have been modified with the appropriate additives. As a previous stage to the development of the materials described above, the effects produced by the addition of two carbon-based nanofillers: graphene nanoplatelets and carbon nanotubes, using as a matrix a high-performance polymer, polyetheretherketone (PEEK) have been studied in this thesis. Furthermore, the composite materials used in the current work were fabricated using industrial processes (melt-compounding and injection-moulding). The multiscale materials (carbon fibre laminates) were created through a novel two-step film stacking process. Both nanofillers increased the viscosity of PEEK, making its processing even more challenging. In the case of the carbon fibre laminates, the high viscosity of the nanocomposite matrix produced an increase in the thickness of the laminate and the volume fraction of the matrix. The addition of graphene nanoplatelets and carbon nanotubes increased the mechanical properties, in addition to the thermal conductivity of PEEK. However, only high percentages of carbon nanotubes (5 and 10 wt.%) produced a significant improvement in the electrical conductivity of PEEK. In the case of carbon fibre laminates, the addition of nanofillers increased the elastic modulus, but the rest of the mechanical properties decreased. Both nanoreinforcements increased the electrical and thermal conductivity of the laminates in through-thickness direction. On the other hand, the volume fraction of carbon fibre played a key role in the in-plane electrical and thermal conductivity.