Thermal aging of acrylic-urethane network: Kinetic modeling and end-of-life criteria combined with mechanical properties

This study addresses the multiscale analysis of acrylic urethane networks (AUN). To establish the kinetic model for predicting AUN oxidation, this study considered the pure thermal oxidation of AUN at 160, 180, and 200 degrees C. Chemical changes were monitored using infrared spectroscopy. These indicated the presence of an imide, presumably generated from the oxidation of CH2 at the alpha-position of nitrogen. On the macromolecular and macroscopic scales, oxidation was shown to induce predominant crosslinking, leading to a drop in toughness (i. e., embrittlement). The novel kinetic model of AUN thermal aging was developed from a mechanistic scheme previously established for polyamide 11, by adding some extra paths of thermolytic alkyl radical formation, oxidative N-H bonds decomposition and coupling of aminyl radicals.

Automated summary

This study investigates the multiscale analysis of acrylic urethane networks (AUN) and establishes a kinetic model for predicting AUN oxidation. By monitoring chemical changes during pure thermal oxidation of AUN, it was found that oxidation induces predominant crosslinking and decreases toughness. The novel kinetic model for AUN thermal aging was developed based on a mechanistic scheme previously established for polyamide 11.