Influence of different alkyl‐methylimidazolium tetrafluoroborate ionic liquids on the structure of pebax® films. Consequences on thermal, mechanical, and water sorption and diffusion properties. Issue 8 (22nd December 2015)

• Record Type: Journal Article
• Authors: Magana, Sylvain; Gain, Olivier; Gouanvé, Fabrice; Espuche, Eliane
• Is Part Of: Journal of polymer science. Volume 54:Issue 8(2016)
• Page Start: 811
• Page End: 824
• Publication Date: 2015-12-22
• Subjects: diffusion -- hydrophilic polymers -- mechanical properties -- microstructure -- structure‐property relations -- thermal properties; 547
• DOI: 10.1002/polb.23977
• Languages: English
• ISSNs: 0887-6266

Abstract

ABSTRACT: In this work, three ionic liquids (ILs) differing by the length of the alkyl chain linked to their cation were incorporated in a Pebax ® copolymer matrix through a solvent cast process for composition from 0 to 70 wt % IL. The copolymer/IL miscibility was investigated via IR Spectroscopy, Differential Scanning Calorimetry and Scanning Electron Microscopy. The three ILs dissolved in the copolymer soft phase for ILs content below 30 wt % whereas they formed segregated dispersed domains at higher loadings. The plasticizing effect of the ILs was examined through DSC and thermomechanical analyses. In the range of IL amount from 0 to 30 wt %, no significant differences were observed in the thermomechanical properties as a function of the IL structure. At higher IL content, the films based on 1‐ethyl‐methylimidazolium tetrafluoroborate sustained better properties. All films exhibited a good thermal stability up to 300 °C. The water sorption isotherms were modeled with GAB equation and both the kinetic and thermodynamic parameters of the sorption mechanism were investigated. A non‐monotonic evolution of the GAB parameters and diffusion coefficient as a function of the IL content was evidenced. Moreover, different behaviors were observed as a function of the IL nature and structuration within the copolymer matrix. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2016, 54, 811–824 Abstract : This work addresses the optimization of the water transport properties of a copolymer film due to the introduction of ionic liquid (IL) moieties. The polymer/ionic liquid miscibility is investigated for a large range of compositions. The impact of ionic liquid content and its alkyl chain length is also studied in terms of the film morphology and their thermal stability, thermomechanical properties and water diffusion and sorption properties. The best properties are achieved for low length of the ionic liquid alkyl chain and totally miscible systems.