Title: Frustration of Thermoset Network Packing by Tunable Aromatic Backbone Isomerism for Matrix Strain Capability Control

Authors: Andrew T. Hollcraft, Jeffrey S. Wiggins

DOI: 10.33599/nasampe/s.24.0250

Abstract: Many highly aromatic thermoset matrices suffer from low strain capability, leading to brittle failure. Network-level toughening approaches have primarily focused on the incorporation of flexible monomers with aliphatic or cycloaliphatic moieties to enhance elongation at failure with general reductions in modulus and glass transition temperature. A significantly less explored approach to network toughening involves aromatic isomerism. In this approach, meta-substitutions of aromatic rings are hypothesized to improve packing efficiency compared to para-substitutions. Enhanced network packing reduces the distances between segments of the network, resulting in increased dipole-dipole interactions, pi-pi stacking, and steric hindrance, ultimately leading to higher modulus. This research investigates the concept of tunable aromatic backbone isomerism as a monomer design strategy for deliberately frustrating angstrom-level network packing efficiency to control strain capability in thermoset networks. A library of aromatic diamine isomers of approximately 500 g/mol were synthesized and employed in epoxide-amine thermosets to prepare networks of well-defined topology differing only in aromatic backbone isomerism. Frustration of network packing was characterized by density and water absorption and the resulting influence on thermomechanical performance was characterized by uniaxial compression testing and dynamic mechanical analysis.

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Conference: SAMPE 2024

Publication Date: 2024/05/20

SKU: TP24-0000000250

Pages: 10

Price: $20.00