Transport properties of thermoplastic/thermoset blends

J Polym Sci B Polym Phys

et al. 2015

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

\frac{1}{T g} = \frac{w_{normala}}{{T g}_{normala}} + \frac{w_{normalb}}{{T g}_{normalb}}

Section: Resultsmentioning

confidence: 99%

Influence of different alkyl‐methylimidazolium tetrafluoroborate ionic liquids on the structure of pebax^® films. Consequences on thermal, mechanical, and water sorption and diffusion properties

Magana

Gain

J Polym Sci B Polym Phys

et al. 2015

“…The PVOH content varied from 3.5 to 30 vol %. Prior to the processing step, the EVOH pellets and PVOH powder were dried at 90 C during 48 h. Due to their different melting points and processing conditions (in the range from 200 to 250 C for EVOH [1][2][3][4][5][6] and from 220 to 230 C for PVOH 7 ), preliminary tests (not shown here) were investigated to determine the optimal melt blending temperature and duration allowing to melt both components while avoiding their degradation. The processing conditions were as follows: EVOH pellets and PVOH powder were incorporated in one step into the 50 cm 3 mixing chamber and melt blended for 10 min at 225 C. The rotor speed was fixed at 50 rpm.…”

Section: Blends and Films Preparationmentioning

confidence: 99%

“…Polymer blends represent one of the possible routes to tune material properties . In this context, the choice of the components and composition as well as the development of strong interfacial adhesion represents major criteria for the final properties.…”

Section: Introductionmentioning

confidence: 99%

“…Polymer blends represent one of the possible routes to tune material properties. [1][2][3][4][5] In this context, the choice of the components and composition as well as the development of strong interfacial adhesion represents major criteria for the final properties. Because of its high initial barrier properties, EVOH was rarely involved in polymer blends as major phase to decrease its permeability and reduce the impact of hydration.…”

mentioning

confidence: 99%

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Morphology, mechanical, and water transport properties of melt blended EVOH/PVOH films

Blanchard

J Polym Sci B Polym Phys

Espuche

2019

Herein, we report for the first time the successful preparation of ethylene–vinyl alcohol (EVOH)/poly(vinyl alcohol) (PVOH) blends by a melt blending process for PVOH volume content ranging from 0 to 30%. Thermal stability up to 270 °C was maintained for all blends. The blends morphology consisted in spherical low size PVOH domains homogeneously dispersed in the EVOH matrix with good interfacial properties. An increase of the mean size of the PVOH domains (from 0.3 to 1.2 μm) and of the size distribution was evidenced as the PVOH content increased. The contribution of each phase to the water sorption and diffusion was clearly demonstrated. The impact of water uptake was investigated on the chains mobility by using Gordon–Taylor law and on the mechanical properties of the blends with respect to the reference polymers. It was pointed out that the reinforcing effect of PVOH phase decreased as the water activity increased. However, a significant elongation at break was maintained, underlining the major role played by the EVOH continuous phase at high water activity. Finally, it was shown that adding PVOH to EVOH up to 15 vol % allowed strengthening the material at low water activity and keeping interesting elongation at break and barrier properties at high water activity. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 838–850

“…Moreover, high quality filler dispersion state is generally difficult to obtain by melt‐blending process 10–13 . The polymer blend approach seems then to be a good alternative as it usually allows tuning the barrier and mechanical properties 14–19 . However, only few studies were performed in order to decrease the permeability of EVOH by blending with another polymer.…”

Section: Introductionmentioning

confidence: 99%

Influence of the PVOH molar mass on the morphology and functional properties of EVOH/PVOH films prepared by melt blending

Blanchard

Mélis

Journal of Polymer Science

et al. 2020

The influences of the molar mass (low, medium, and high) and content of poly(vinyl alcohol) (PVOH) dispersed by melt-blending in an ethylene vinyl alcohol (EVOH) copolymer on the morphology, microstructure, thermal, mechanical, and oxygen barrier properties were investigated. Multilayer films with external low-density polyethylene layers and inner EVOH/PVOH blend layer and respective monolayer films were elaborated and characterized. EVOH/PVOH blends exhibited a good compatibility because of the initial presence of PVOH segments in EVOH. The detailed quantitative analysis of the morphology performed for all blends showed that the finest dispersion was obtained with the PVOH with the lowest molar mass. The properties of the films as a function of the PVOH content and its molar mass were determined herein. Significant improvement of barrier properties was obtained at moderated water activities (up to a w = 0.6) by using the PVOH with the lowest molar mass. Compared to the neat EVOH material, the oxygen permeability coefficients decreased by a factor 2 by adding 15 vol% PVOH while the thermal and mechanical properties remained similar.