Pushing the Fundamentals of Mechanical Composite Recycling

• Applicant: Dr. Valentin Dalbauer
• Subject Area: Polymeric and Biogenic Materials and Derived Composites ; Synthesis and Properties of Functional Materials ; Plastics Engineering ; Polymer Materials
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 572437015

Composites are frequently used, high-performance materials in many fields. Depending on the matrix material of the composite different strategies exist to deal with the waste after the product life ends like landfill, incineration, or recycling. The last one is of special interest in the perspective of a sustainable transformation and future. Mechanical recycling shows potential from an economical and environmental perspective. This research proposal deals exclusively with this type of composite recycling by focusing on the interactions and interface properties in heterogenic systems from a fundamental point of view. The objective of this research project is to characterize and model the interface properties of recycled, thermoset based composites from a fundamental perspective. Therefore, virgin composites as well as aged ones and their combinations, which are derived from an extensive literature research, will be investigated to determine and quantify the interactions on length scales below the macroscopic level. Additionally, state-of the art modelling methodologies will be used to transfer experimentally gained insights to generalized, digital models. Basic material and interface properties of virgin and artificially aged materials including composites and their matrix, will be obtained by a comprehensive experimental design. Standardized mechanical properties such as tensile and bending properties and advanced fracture mechanic properties as for example strain energy release rates are part of this characterization. Hereby, the artificial aging process includes the influence of different radiation types, humidity and temperature inspired by real world conditions. Backed by the experimental data sets traction-separation and micromechanical modelling approaches for heterogeneous systems will be used to formulate and derive accurate models to predict the interface properties of aged composites. Furthermore, novel molecular dynamic simulations are applied for the prediction of the interface properties. Recent studies in the field of mechanical composite recycling focus on the macroscopic behavior of resulting materials or structures made from recycled constituents. However, these studies often overlook the fundamental interactions on a molecular and microscopic level. For a holistic evaluation of the potential and significance of mechanical composite recycling, a deep understanding of the fundamental interface interactions between different constituents is crucial. This project will be the first to address a characterization of interface interactions in mechanically recycled, thermoset based composites under controlled aging and testing conditions. However, numerical models are derived and implemented in finite element solvers by conducting novel molecular dynamic simulations for the first time in this perspective.

• DFG Programme: Research Grants
• International Connection: Austria
• Cooperation Partner: Dr. Umut Cakmak