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Study of Hyperbranched Poly(ethyleneimine) Polymers of Different Molecular Weight and Their Interaction with Epoxy Resin

Departament de Màquines i Motors Tèrmics, Escola Superior d’Enginyeries Industrial, Aeroespacial i Audiovisual de Terrassa, Universitat Politècnica de Catalunya, Barcelona Tech, Carrer de Colom 11, 08222 Terrassa, Spain
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These authors contributed equally to this work.
Materials 2018, 11(3), 410; https://doi.org/10.3390/ma11030410
Received: 8 February 2018 / Revised: 1 March 2018 / Accepted: 4 March 2018 / Published: 9 March 2018
Two different commercial hyperbranched poly(ethyleneimine)s (HBPEI), with molecular weights (MW) of 800 and 25,000 g/mol, and denoted as PEI800 and PEI25000, respectively, as well as the mixtures with a Diglycidyl Ether of Bisphenol-A (DGEBA) epoxy resin, have been studied using thermal analysis techniques (DSC, TGA), dielectric relaxation spectroscopy (DRS), and dynamic mechanical analysis (DMA). Only a single glass transition is observed in these mixtures by DSC. DRS of the HBPEIs shows three dipolar relaxations: γ, β, and α. The average activation energy for the γ-relaxation is similar for all HBPEIs and is associated with the motion of the terminal groups. The β-relaxation has the same average activation energy for both PEI800 and PEI25000; this relaxation is attributed to the mobility of the branches. The α-relaxation peak for all the HBPEIs is an asymmetric peak with a shoulder on the high temperature side. This shoulder suggests the existence of ionic charge trapped in the PEI. For the mixtures, the γ- and β-relaxations follow the behaviour of the epoxy resin alone, indicating that the epoxy resin dominates the molecular mobility. The α-relaxation by DRS is observed only as a shoulder, as a consequence of an overlap with conductivity effects, whereas by DMA, it is a clear peak. View Full-Text
Keywords: hyperbranched polymers; poly(ethyleneimine); epoxy resin; dielectric relaxations; dynamic mechanical relaxations hyperbranched polymers; poly(ethyleneimine); epoxy resin; dielectric relaxations; dynamic mechanical relaxations
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Román, F.; Colomer, P.; Calventus, Y.; Hutchinson, J.M. Study of Hyperbranched Poly(ethyleneimine) Polymers of Different Molecular Weight and Their Interaction with Epoxy Resin. Materials 2018, 11, 410.

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