Nanomaterials for advanced composites

Inclusion of carbon nanotubes (CNTs) into a polymer matrix provides potential for creating materials with multifunctional properties. However, several issues need to be overcome to successfully introduce electrically conductive nanoparticles into polymer composite laminates. For example, the increased viscosity of resin and the filtration of nanoparticles lead to defective laminates. Another important issue related to the increasing use of carbon fibre reinforced polymers (CFRPs) is the lack of reliable methods for quality control.

The EU-funded project ELECTRICAL (Novel aeronautical multifunctional composite structures with bulk electrical conductivity and self-sensing capabilities) worked on further developing the exciting potential of nano-reinforced resins in terms of their electrical and mechanical properties.

Scientists worked on alternative emerging methods for manufacturing nano-reinforced carbon-based composites compatible with current industrial manufacturing processes of composites. Various state-of-the-art fabrication technologies to convert CNT nanofillers into engineered multifunctional preforms, prepregs or buckypapers were considered for further use in CFRP structures. Incorporation of nanofillers into toughened thermoplastic fibres or non-woven veils helped overcome the resin-increased viscosity and filtration effects.

ELECTRICAL exploited the CNT properties as polymeric resin doping to develop novel multifunctional composite structures with bulk electrical conductivity and self-sensing capabilities.

Dielectric mapping helped monitoring and optimising the CFRP curing process. This technique takes advantage of the CNT electrical conductivity to perform non-invasive electrical measurements of the material in the vicinity of the dielectric sensor. Furthermore, the piezoresistive CNT behaviour enabled development of innovative CFRP structures with distributed or localised self-sensing capabilities, enabling quality assurance of the final component.

ELECTRICAL activities and outcomes should help increase the competitiveness of European aeronautical companies against their international counterparts. The primary market is composite fuselage parts for the next generation of large aircraft. In addition, the advanced composite materials may find applications in other markets such as space, automotive and rail.