Thermo-reversibly cross-linked rubber networks with Diels-Alder Chemistry Lorenzo M. Polgar1,2,*, Anton A.Broekhuis1, Francesco Picchioni1,2 1. University of Groningen, Department of Chemical Engineering, Nijenborgh 4, 9747 AG, the Netherlands 2. Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven, the Netherlands *[email protected] ABSTRACT Industrial maleinized ethylene-propylene rubbers[1] were thermo-reversibly crosslinked in a simple two-step approach. In the first step, the pending anhydride rings (2,1wt%)[2] were modified with furfurylamide.[3] The resulting grafted furans were then used to cross-link the rubbers with different aliphatic bismaleimides via a Diels-Alder coupling reaction.[4-6] The mechanical properties and the temperature response of the resulting products were typical for cross-linked rubbers.[7] Reversibility of the system was proven by cutting used material into pieces and pressing those into new homogeneous samples with the same properties.[8, 9] The resulting system is flexible as it allows for tuning of its material properties by varying the cross-link density and the presence and type of cross-link agent. The chemistry was applied to different (polymer) systems and composites.[10] Acknowledgement This research forms part of the research programme of the Dutch Polymer Institute (DPI), project #749 References [1] P. Sutanto, E. Picchioni, L. P. B. M. Janssen, K. A. J. Dijkhuis, W. K. Dierkes and J. W. M. Noordermeer, "State of the art: Recycling of EPDM rubber vulcanizates," International Polymer Processing, vol. 21, (2006) [2] M. van Duin, "Grafting of polyolefins with maleic anhydride: Alchemy or technology?" Macromolecular Symposia, vol. 202, pp. 1-10 (2003) [3] M. A. J. van der Mee, J. G. P. Goossens and M. van Duin, "Thermoreversible cross-linking of maleated ethylene/propylene copolymers with diamines and amino-alcohols," Polymer, vol. 49, ( 2008) [4] Y. Zhang, A. A. Broekhuis and F. Picchioni, "Thermally Self-Healing Polymeric Materials: The Next Step to Recycling Thermoset Polymers?" Macromolecules, vol. 42, pp. 1906-1912 (2009) [5] C. Toncelli, D. C. De Reus, F. Picchioni and A. A. Broekhuis, "Properties of Reversible Diels-Alder Furan/Maleimide Polymer Networks as Function of Crosslink Density," Macromolecular Chemistry and Physics, vol. 213, pp. 157-165 (2012) [6] R. Gheneim, C. Perez-Berumen and A. Gandini, "Diels-Alder reactions with novel polymeric dienes and dienophiles: Synthesis of reversibly cross-linked elastomers," Macromolecules, vol. 35 (2002) [7] W. Hofmann, Rubber Technology Handbook. Hanser Publishers (1989) [8] S. A. Canary and M. P. Stevens, "Thermally Reversible Cross-Linking of Polystyrene Via the Furan-Maleimide Diels-Alder Reaction," Journal of Polymer Science Part A-Polymer Chemistry, vol. 30 (1992) [9] H. Laita, S. Boufi and A. Gandini, "The application of the Diels-Alder reaction to polymers bearing furan moieties .1. Reactions with maleimides," European Polymer Journal, vol. 33, pp. 1203-1211 (1997) [10] N. Nakajima and Y. Yamaguchi, "Effect of fillers and rubber structures on tensile behavior of filled, unvulcanized compounds of cis-1,4-polybutadienes," J Appl Polym Sci, vol. 66, pp. 1445-1453 (1997)