Processing of Carbon Nanotubes by Press Molding
IGESTEK has extensive experience in the development of projects focused on the application of polymeric compounds. In this desire to maintain leadership, it draws on new developments from Technology Centers and companies in the sector to create applications close to the market. In this sense, the Agent of the RVCTI TECNALIA, has a technology for manufacturing nanomaterials called Buckypapers. This type of materials has a great potential for application in the industry, due to its excellent thermal and mechanical properties, so IGESTEK is aware of it.
A Buckypaper (BP) consists of a thin, light and flexible sheet, composed of 100% Carbon Nanotubes (CNTs) that are interconnected and randomly placed.
Due to its properties, BP can be used as a heating element in a resistive heating system, since it is capable of heating up evenly (in a short period of time) when an electric current is applied to it, as well as resisting high temperatures. This, together with its lightness (thicknesses in the range of 30-90 microns, with grammages of 30-60gsm), makes BP a very attractive material for use in the transport sector.
Knowing the multiple advantages that this material offers and its wide field of application, IGESTEK has developed a hybridization process of Nanomaterials (Buckypapers) with Thermoplastic Composite Materials through Press Molding, in order to obtain a functionalized BiW demonstrator, specifically , a bonnet of a car.
The hybridization process developed consists of sandwiching a Buckypaper (carbon nanotube film) between two sheets of thermoplastic composite (fiberglass-reinforced polypropylene). Through temperature, pressure and tooling strategy, it is possible to obtain a single component with a built-in heating element.
The increase in the number of pedestrian and cyclist accidents has increased the demand for new safety elements such as “external airbags” for automobiles. This, together with the need to manufacture lighter vehicles to reduce fuel consumption or increase the autonomy of electric vehicle batteries, gave rise to the concept of the bonnet developed by IGESTEK.
The proposed solution is based on a bonnet formed from two sheets of thermoplastic composite to which a buckypaper is inserted in the area where the airbag system would be housed. The buckypaper acts as a heating element to keep the system at an adequate temperature (in any atmospheric and weather condition, especially in cold climates) and thus offer optimal and controlled panel rupture in the event of a collision when the external airbag is activated. The buckypaper would be powered by the car’s battery and would be managed through the ECU.
Several prototypes were manufactured in order to validate, through thermal and mechanical tests, the developed technology. It was possible to obtain an electro-thermal system embedded in a thermoplastic composite structure, capable of providing homogeneous and stable heating.
The processing of carbon nanotubes into thermoplastic composites by press molding is a completely new process with great exploitation potential. Nanomaterials, which have extraordinary properties, open up a wide range of possible applications for IGESTEK, and not only for the automotive sector but also for the industry in general.