1. Enabling simultaneous reprocessability and fire protection via incorporation of phosphine oxide monomer in epoxy vitrimer.
- Author
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Huang, Zhenyu, Wu Klingler, Wenyu, Roncucci, Daniele, Polisi, Carolina, Rougier, Valentin, Lehner, Sandro, Jovic, Milijana, Rentsch, Daniel, Dul, Sithiprumnea, Hedlund, Karin Brändli, Michaud, Véronique, Wang, Zhengzhou, and Gaan, Sabyasachi
- Subjects
FIRE prevention ,FIREPROOFING ,EPOXY resins ,MONOMERS ,GLASS transition temperature ,PHOSPHINE oxides - Abstract
• Novel phosphine oxide-containing bio-based anhydride was synthesized and used as epoxy curing hardener. • Flame-retardant epoxy vitrimer contains carboxylic ester network. • The EV exhibits excellent flame retardancy attributed to both gas and condense-phase actions. • Carboxylic ester dynamic bonds impart excellent reparability and reprocessability. • The EV exhibits excellent mechanical performance before and after recycling. The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science, offering a material solution that is not only superior in fire safety but is also environment friendly. Herein, a flame-retardant epoxy vitrimer (EV) was prepared using partially bio-based IADPPO (diphenylphosphine oxide itaconic anhydride) and citric acid as curing reagents via a solvent-free process. Their incorporation created covalent adaptable networks (CANs) in the matrix which promote reprocessability and recyclability. The EV exhibits excellent thermal stability with high initial decomposition temperature (T - 5wt% ∼308 °C) and high glass transition temperature (T g ∼107 °C), similar to the blank EV (115 °C). The flame retardancy, mechanical properties, transesterification-based reprocessability, and flame-retardant mechanism were investigated. The EV containing 3 wt% phosphorus (EV IADPPO 3P) achieved UL-94 V0 classification with a limiting oxygen index (LOI) of 27%, while the virgin sample Blank EV (without phosphorus) burned completely. Additionally, increased flexural strength of 79% was observed for EV IADPPO 3P compared to Blank EV. Furthermore, the flame-retardant EV showed high malleability and reparability that could be thermomechanically reprocessed without sacrificing the thermal, mechanical, and flame-retardant properties. Thus, the newly developed epoxy vitrimer is not only fire-safe but fulfills the sustainability goals of today's society. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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