Development and validation of recycled carbon fiber-based binder tapes for automated tape laying processes

Abstract

The current growth in use of fiber reinforced polymer composites causes a strongly increasing amount of waste. Current approaches for fiber reinforced polymer composites recycling usually not exploit the potential of endless fibers as they are shortened during recycling and will not be properly aligned in the final product. Considering this, the present work aimed at the development of a recycling process for long recycled carbon fibers, where fiber length is preserved and load-related fiber orientation is possible. The starting point for the presented work was so-called slivers, which are long bundles of fibers resulting from a carding process that has been applied to fiber scrap. The main focus of this work was on the development of a binder mesh application rig that processes the sliver to a binder tape, processable in an automated tape laying process, which in turn required modifications to adapt to the novel tape. The functionality of the binder tape manufacturing process was validated with long recycled carbon fibers slivers with linear density of 4 g/m and fiber lengths between 70 and 120 mm. With the binder tape preform manufactured this way, two alternative routes for composite manufacturing were tested. First, the amount of binder was set so high that direct thermoplastic pressing of the preforms was possible. Second, the amount of binder was minimized, and the preforms were infiltrated with a thermoset resin system via resin transfer molding. While the thermoplastic route showed very deficient fiber–matrix adhesion, with the thermoset route, ≈68% of stiffness and ≈31% of strength of virgin fiber-based composites could be achieved in fiber direction in a unidirectional lay-up.

A Review of Recent Developments in Composites Made of Recycled Carbon Fiber Textiles

“…Throughout these processes, careful consideration of applied forces must be made to ensure that the fiber length does not degrade to an unacceptable extent. The unspun slivers can be used to produce non-crimp fabrics [26] and tapes [27][28][29] for consolidation via compression molding. The spun yarns can be wrapped around a mandrel [30,31] or woven into fabrics [32,33] for compression molding.…”

“…They showed that a homogeneous blend was possible with minimal thickness variation and good tensile strength. Rimmel et al [29] at the Institute for Composite Materials in Germany produced highly aligned composites from 150 mm long recycled carbon fibers. The tapes were produced by carding the fibers mixed with PA6 fibers and drawing the web into a sliver.…”

Thermal Aging of Menzolit BMC 3100

“…Specific emphasis is also laid on the manufacturing of spare parts from thermoplastic, thermosetting plastics, and short and continuous fibre-reinforced composites. In [9][10][11][12], the authors offer insights on some recent technological and environmental applications of reinforced polymers. In [13], the author noted that Menzolit BMC 3100 is a special material developed for the automotive industry to produce headlights.…”

Modeling transverse micro flow in dry fiber placement preforms

“…As they are manufactured with a fixed production width, preforming usually leads to high scrap rates of up to 50%, [3][4][5][6] reducing economy and sustainability of the process and inducing the need of recycling of in-house scrap. 7 In addition, when aiming at highest performance of manufactured parts, loadrelated fiber orientations within the preform are necessary, which is not easy to achieve with two-dimensional semi-finished textile products and also further increases scrap rates. One possibility to overcome these drawbacks is using direct preforming technologies such as dry fiber placement (DFP), sometimes also referred to as automated dry fiber placement.…”