Network structure and thermomechanical properties of hybrid DGEBA networks cured with 1‐methylimidazole and hyperbranched poly(ethyleneimine)s |
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| Authors: | Xavier Fernández‐Francos David Santiago Francesc Ferrando Xavier Ramis Josep M Salla Àngels Serra Marco Sangermano |
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| Institution: | 1. Department of Mechanical Engineering, Universitat Rovira i Virgili, C/Pa?sos Catalans 26, 43007 Tarragona, Spain;2. Thermodynamics Laboratory, ETSEIB, Universitat Politècnica de Catalunya, Av. Diagonal 647, 08028 Barcelona, Spain;3. Department of Analytical and Organic Chemistry, Universitat Rovira i Virgili, C/ Marcel·lí Domingo s/n, 43007 Tarragona, Spain;4. Department of Applied Science and Technology, Politecnico di Torino, Corso Duca Degli Abruzzi 24, 10129 Torino, Italy |
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| Abstract: | The use of commercially available hyperbranched poly(ethyleneimine)s (Lupasol?, BASF) as polymeric modifiers in diglycidyl ether of bisphenol A thermosetting formulations using 1‐methylimidazole (MI) as anionic initiator has been studied. Poly(ethyleneimine)s can get incorporated into the network structure by condensation of amine and epoxy groups. The excess, over‐stoichiometric epoxy groups can undergo anionic homopolymerization initiated by MI. The thermal, dynamomechanical, and mechanical properties of the resulting materials have been determined using DSC, thermomechanical analysis (TMA), dynamomechanical analysis (DMA), and mechanical testing. The effect of the different amine modifiers on the MI networks, determined by their structure, is complex. Low initiator content and high molecular weight modifiers create significant mobility restrictions, which have a strong effect on the glass transition temperature and the apparent crosslinking density of the cured materials. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 |
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| Keywords: | epoxy thermosets hyperbranched impact strength mechanical properties network structure thermal properties thermomechanical properties thermosets |
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