Thermoplastic composites are in many ways very different from conventional thermoset composites.

Placement and Consolidating

The matrix system is thermoplastic which doesn't need curing. It can be melted and cooled time and time again, which allows for much faster processing and assembly techniques. Prepreg tapes are joined together by melt-fusion to form the laminate. With fibre placement methods and in-situ consolidation, the tapes are placed on the product and are fused together in one step, which elimates a subsequent consolidation or curing step. We use this method at Airborne Composite Tubulars to manufacture thermoplastic composite tubulars, with our unique Continuous Winding technology. An alternative technology is a two-step process, in which a fast lay-down is used with a secondary fast consolidation cycle in oven, autoclave or heated mould. Both methods are much faster than the chemical curing of thermosets.

Welding

Parts can be assembled by welding or co-consolidation. Airborne is developing proprietary welding techniques for fast and simple assembly. Welding of thermoplastic composites gives the optimal composite-composite interface strength, since the matrix material itself is used for the weld, instead of a separate adhesive layer as with thermosets. If one part of the assembly is made in a consolidation step for example with oven consolidation, other parts can be joined by co-consolidation which eliminates an extra assembly step.

Material behaviour

The materials have ductile behaviour as opposed to the brittle nature of thermoset composites such as carbon-epoxy. This greatly improves the toughness and impact behaviour of the composite part, a critical issue with thermosets. For example in aerospace applications, the design allowables are improved with thermoplastics which leads to lighter designs. The ductile behaviour also allows for much larger deformations, which is a important feature of the spoolable thermoplastic composite tubulars that Airborne has developed. This ductile behaviour can also dramatically improve the fatigue resistance. Another advantage of thermoplastics is the superior chemical resistance, especially for the high-performance thermoplastic materials. For very low, cryogenic temperatures thermoplastics outperform thermosets by maintaining adequate mechanical properties.

Experience

Airborne works with many different materials, from industrial grades such as HDPE, PP, PA11/12, PVDF up to high-performance polymers such as PPS, PEKK and PEEK. In our business unit Airborne Composite Tubulars we have a production line operational, and are scaling up to a full-fledged production facility. Our researchers of the Airborne Technology Centre are deeply involved in the international research community on thermoplastics, for example through the TAPAS and TC-SKAR programmes, and are developing new fast and cost-efficient production methods.

If you are interested in participating in our research programs, or have materials, processes or technologies that can support these topics, you are more than welcome to contact us, via our general contact details or directly via CTO This e-mail address is being protected from spambots. You need JavaScript enabled to view it