Dielectric behaviour of an epoxy network cured with a phosphonium-based ionic liquid

POLYMER

卷:222

Article

Lefort, Thibaut^1,2  Duchet-Rumeau, Jannick¹  Livi, Sebastien¹  Bachellerie, Damien²  Pruvost, Sebastien¹ 

[1] Univ Lyon, Imp Ingn Mat Polymeres, INSA Lyon, UMR CNRS 5223, F-69621 Villeurbanne, France

[2] SuperGrid Inst, SAS 23,Rue Cyprian,BP 1321, F-69611 Villeurbanne, France

关键词: Epoxy networks;    Ionic liquids;    Dielectric properties;    Electrical conductivity;    Structure property relationships;    Molecular mobility;    Electrical insulation applications;   

DOI  :  10.1016/j.polymer.2021.123645

来源: Elsevier

【 摘 要 】

Phosphonium based ionic liquids (ILs) have been previously shown as a new emerging class of initiator of epoxy prepolymers. The present study aims at investigating the influence of ILs on the dielectric behaviour of epoxy-IL systems by dielectric spectroscopy. Here, the content of IL incorporated in the epoxy prepolymer has a significant impact on the final properties of the polymer networks displaying a high glass transition temperature (Tg > 160 degrees C). The excess of IL (>10 phr) acts as a plasticizer agent decreasing the Tg and leading to the formation of heterogeneities. Moreover, the study of alpha and beta conventional relaxation modes by dielectric spectroscopy highlighted an increase of chain mobility due to IL excess. A omega relaxation mode has been noticed with the addition of high content of IL, probably relating to heterogeneities of the network. Unlike the most of polymer systems, the study of the DC conductivity by the application of an Arrhenius law demonstrated a thermal activation mechanism, independent from the free volume and the glass transition phenomenon. A discussion on the identification of charge carriers has been finally proposed.

【 授权许可】

Free