title: The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry.
abstract: A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ethylene-propylene rubber, grafted with maleic anhydride, is thermo-reversibly cross-linked in two steps. The pending anhydride moieties are first modified with furfurylamine to graft furan groups to the rubber backbone. These pendant furan groups are then cross-linked with a bis-maleimide via a Diels-Alder coupling reaction. Both reactions can be performed under a broad range of experimental conditions and can easily be applied on a large scale. The material properties of the resulting Diels-Alder cross-linked rubbers are similar to a peroxide-cured ethylene/propylene/diene rubber (EPDM) reference. The cross-links break at elevated temperatures (> 150 °C) via the retro-Diels-Alder reaction and can be reformed by thermal annealing at lower temperatures (50-70 °C). Reversibility of the system was proven with infrared spectroscopy, solubility tests and mechanical properties. Recyclability of the material was also shown in a practical way, i.e., by cutting a cross-linked sample into small parts and compression molding them into new samples displaying comparable mechanical properties, which is not possible for conventionally cross-linked rubbers.
authors: Department of Chemical Engineering, University of Groningen; Dutch Polymer Institute (DPI); l.m.polgar@rug.nl.
authors: Lorenzo Massimo
authors: LM
authors: Polgar
authors: Department of Chemical Engineering, University of Groningen.
authors: Martin
authors: M
authors: van Duin
authors: Department of Chemical Engineering, University of Groningen.
authors: Francesco
authors: F
authors: Picchioni
mesh_terms: D061565:Cycloaddition Reaction; D012408:Rubber / Q000737:chemistry*; D013696:Temperature
chemical_list: D012408:Rubber