Characterisation of composite materials from aligned dry laid nonwovens based on rCF from hydrogen tanks
Topic(s) : Special Sessions
Co-authors :
Violetta SCHUMM (GERMANY), Frank MANIS (GERMANY)Abstract :
The use of fibre composites is becoming increasingly important in the manufacturing of hydrogen tanks for future mobility. The structural shell of Type 4 hydrogen tanks, are made from carbon fibre-reinforced plastics [1]. However, the use of this material class also requires a proper recycling concept to justify the use of such a high-energy consuming material [2]. This topic is addressed in the European research project called Cider (funding reference: 033RU018A).
In the project, the first step after the production of the tank is the fiber-matrix separation, including shredding of the tanks. The recycled carbon fibers are then processed into dry-laid nonwovens, which can be combined with various resin systems. These composites can be reused in the automotive or train industry. The aim of this study is to investigate the composite properties and their fibre orientation on the basis of rCF nonwovens.
The unique feature of these nonwovens is their continuous longitudinal orientation, allowing for anisotropic properties in the composites and the use of large-area textiles (up to 2m wide) as semi-finished products (can be seen in figure 1).
The dry-laid nonwoven technology is used for production, utilizing a carding machine in combination with a longitudinal lapper to retain the orientation along the production direction, achieved in the card pile. A ratio of approximately 3:1 (based on bending stiffness) is achieved. A comparison is made between different types of recovered fibers (pyrolysis and solvolysis).
The semi-finished products are impregnated using a wet compression moulding with an epoxy resin system and the thermoplastic Elium resin from the project partner Arkema (see figure 1). The composites are analysed in terms of their tensile and bending properties. Eddy current measurement provides information on the homogeneity and fibre orientation of the semi-finished products. The determination of the fibre volume content, micrographs, as well as individual fibre characterisation complete the test methods.
Initial results show promising bending properties: The flexural strength at 0° is around 430 MPa and flexural stiffness at 0° is around 26 GPa. The fibre volume content was set at around 30 %. For this test panel, rCF- based on solvolysis was used in combination with an epoxy resin system. A comparison of the fibre orientations shows the following: A ratio of 1.63:1 (0°:90°) is calculated on the basis of the eddy current measurement, a ratio of 2.11:1 on the basis of the flexural strength and a ratio of 2.27:1 on the basis of the flexural stiffness. Therefore, a longitudinal orientation can definitively be demonstrated in the nonwoven fabrics and this opens up a higher potential of mechanical properties as well as easier processing into composites because of an improved fiber packing density.
In the project, the first step after the production of the tank is the fiber-matrix separation, including shredding of the tanks. The recycled carbon fibers are then processed into dry-laid nonwovens, which can be combined with various resin systems. These composites can be reused in the automotive or train industry. The aim of this study is to investigate the composite properties and their fibre orientation on the basis of rCF nonwovens.
The unique feature of these nonwovens is their continuous longitudinal orientation, allowing for anisotropic properties in the composites and the use of large-area textiles (up to 2m wide) as semi-finished products (can be seen in figure 1).
The dry-laid nonwoven technology is used for production, utilizing a carding machine in combination with a longitudinal lapper to retain the orientation along the production direction, achieved in the card pile. A ratio of approximately 3:1 (based on bending stiffness) is achieved. A comparison is made between different types of recovered fibers (pyrolysis and solvolysis).
The semi-finished products are impregnated using a wet compression moulding with an epoxy resin system and the thermoplastic Elium resin from the project partner Arkema (see figure 1). The composites are analysed in terms of their tensile and bending properties. Eddy current measurement provides information on the homogeneity and fibre orientation of the semi-finished products. The determination of the fibre volume content, micrographs, as well as individual fibre characterisation complete the test methods.
Initial results show promising bending properties: The flexural strength at 0° is around 430 MPa and flexural stiffness at 0° is around 26 GPa. The fibre volume content was set at around 30 %. For this test panel, rCF- based on solvolysis was used in combination with an epoxy resin system. A comparison of the fibre orientations shows the following: A ratio of 1.63:1 (0°:90°) is calculated on the basis of the eddy current measurement, a ratio of 2.11:1 on the basis of the flexural strength and a ratio of 2.27:1 on the basis of the flexural stiffness. Therefore, a longitudinal orientation can definitively be demonstrated in the nonwoven fabrics and this opens up a higher potential of mechanical properties as well as easier processing into composites because of an improved fiber packing density.