Sustainable Pultruded Sandwich Profiles with Mycelium Core.

This research focuses on exploring the potential of mycelium as a sustainable alternative to wood or solid foam in pultruded glass fiber-reinforced plastic (GFRP) sandwich profiles. The study evaluates the performance and the environmental sustainability potential of this composite by mechanical tests and life cycle assessment (LCA). Analysis and comparison of pultruded sandwich profiles with mycelium, polyurethane (PUR) foam and chipboard demonstrate that mycelium is competitive in terms of its performance and environmental impact. The LCA indicates that 88% of greenhouse gas emissions are attributed to mycelium production, with the heat pressing (laboratory scale) being the main culprit. When pultruded profiles with mycelium cores of densities 350 and 550 kg/m³ are produced using an oil-heated lab press, a global warming potential (GWP) of 5.74 and 9.10 kg CO2-eq. per functional unit was calculated, respectively. When using an electrically heated press, the GWP decreases to 1.50 and 1.78 kg CO2-eq. Compared to PUR foam, a reduction of 23% in GWP is possible. In order to leverage this potential, the material performance and the reproducibility of the properties must be further increased. Additionally, an adjustment of the manufacturing process with in situ mycelium deactivation during pultrusion could further reduce the energy consumption.

Experimental and Simulative Analysis of the Pressure Development in a Closed Injection Pultrusion Process with Multiple Chamber Geometries.

The use of innovative higher-performance highly reactive resin systems requires an enhancement of the established method of fiber impregnation (open bath) towards closed resin-injection pultrusion (CIP), due to the short pot life of the resin systems. The result is that the open bath is developed into a closed injection and impregnation chamber ("ii-chamber"). In this study, three parameters-resin viscosity, opening angle and opening factor at the injection point on the ii-chamber-are varied, each in three stages. For each set of parameters, a pultrusion trial is conducted and the process pressures in the ii-chamber and pultrusion die measured. This enables direct feedback via the process conditions of the as yet uncured composite. The data obtained are used to validate a newly developed simulation model. The model is based on Darcy's law, which has been extended to take fiber movement into account and thus represent the resulting pressure increase in the die. The flexible ii-chamber and die concept enhance our understanding of the processes taking place in the die system. The sensitivity of the process pressures can be shown for the three influencing variables. The experiment shows that of the three influencing variables investigated, viscosity has the greatest sensitivity to pressure development. In general, it can be said that over the length of the pultrusion die system, the pressure level increases across the three measuring points.