The activated anionic ring opening polymerization of ε-caprolactam to polyamide 6 is highly sensitive to external influences such as water. Based on an initial theory, preliminary reaction kinetic tests are carried out with the aim of compensating the influence of the water by increasing the activator and catalyst concentration. Different formulations of activator and catalyst were studied to understand the influence of water on the concentration of activator and catalyst. It was found that the compensation of added water with activator and catalyst restores the original reaction time. The test plates produced are examined with regard to their mechanical characteristics and the polymer properties. The results of the mechanical characterization show no significant impairment after compensation of the added water. The physical properties of the matrix show degradation with repeated compensation. However, the residual ε-caprolactam content remains below the critical value of 1% for three of the four investigated formulations.

The use of fiber reinforced plastics (FRPs) has significant potential to reduce the weight of components. As regards the sustainability of these components, thermoplastic matrices offer more potential for recycling than thermoset ones. A possible manufacturing process for the production of thermoplastic FRPs is thermoplastic resin transfer molding (T-RTM). In this very moisture-sensitive process, ε-caprolactam in addition to an activator and catalyst polymerizes anionically to polyamide 6 (aPA6). The anionic polymerization of aPA6 is slowed down or even completely blocked by the presence of water. This study analyses the sorption behavior of the matrix, fiber, binder and core materials for the production of anionic polyamide 6 composites, which are processed in the thermoplastic RTM process. Water vapor sorption measurements are used to determine the adsorption and desorption behavior of the materials. The maximum moisture loading of the materials provides information about the water adsorption capacity of the material. This knowledge is crucial for correct handling of the materials to achieve a fast process and good properties of the final product.

The reaction kinetics of anionic polymerization for the production of anionic polyamide 6 (aPA6) are widely understood. It is also known that this reaction is very sensitive to external influences such as water. This paper analyzes and quantifies the influence of water on the reaction of ε-caprolactam to anionic polyamide 6. A kinetic model is developed in which the reactive molecules of the activator and catalyst are defined as variables and the concentrations of activator and catalyst as well as water content are considered. A model for the calculation of the reaction kinetics is established and validated with experimental data. The developed model can be used to predict the influence and compensation of water by addition of surplus activator and catalyst during the polymerization of ε-caprolactam.

Pultrusion of continuous fiber reinforced profiles has been state of the art for several decades. However, pultrusion in the production environment so far has no or only few sensor data in a heterogeneous sensor environment, has shortcomings in data quality (time synchronization, different formats, different sampling rates, sporadic disconnections and resulting data losses), and insufficient data processing methods are used for process control and optimization. Significant efficiency improvements would therefore still be possible in this respect. The question therefore arises as to how a data acquisition system can be designed that provides heterogeneous data in a standardized and reliable manner for data-based process development and optimization. The aim is therefore to develop a digitized and standardized data acquisition prototype for the continuous production of sustainable profile structures so flexible that the various components of the production line can be adaptively combined in a central data acquisition system. We have therefore screened and selected possible standardized transmission formats in combination with suitable low-cost data acquisition systems for a highly reliable and secure application area. The paper shows a profound concept for a data acquisition prototype based on different low-cost control systems for the applicability and testability of the developed requirements regarding data acquisition, processing, and future storage.

Urban Air Mobility (UAM) is increasingly recognized as one of the promising methods for future urban transportation, offering higher average speeds than conventional means of transportation. This study investigates the sustainable and efficient production of hollow propeller blades (837 × 85 × 40 mm) using high pressure resin transfer molding (HP-RTM), driven by high demand for UAM, particularly for wingless multicopters. Unlike conventional monolithic or sandwich structures, the propeller blade in this project features a hollow design using a lost core made from water soluble salt.

Compared to reinforcing concrete with steel bars, rebars—made of fiber-reinforced plastic—have a high potential for resource savings in the construction industry due to their corrosion resistance. For the large-volume market of reinforcement elements, efficient manufacturing processes must be developed to ensure the best possible bond behavior between concrete and rebar. In contrast to established FRP-rebars made with thermosetting materials, the use of a thermoplastic matrix enables surface profiling without severing the edge fibers as well as subsequent bending of the bar. The rebars to be produced in this study are based on the process of reactive thermoplastic pultrusion of continuously glass fiber reinforced aPA6. Their surface must enable a mechanical interlocking between the reinforcement bar and concrete. Concepts for a profiling device have been methodically developed and evaluated. The resulting concept of a double wheel embossing unit with a variable infeed and an infrared preheating section is built as a prototype, implemented in a pultrusion line, and further optimized. For a comprehensive understanding of the embossing process, reinforcement bars are manufactured, characterized, and evaluated under parameter variation according to a statistical experimental plan. The present study demonstrates the relationship between the infeed, preheating temperature, and haul-off speed with respect to the embossing depth, which is equivalent to the rib height. No degradation of the Young’s modulus was observed as a result of the profiling process.