کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6746887 | 1429442 | 2018 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Barrier permeation properties of EVOH thin-film membranes under aqueous and non-aqueous conditions
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
مهندسی ژئوتکنیک و زمین شناسی مهندسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Ethylene vinyl alcohol (EVOH) copolymers can provide a superior barrier to hydrocarbons and are increasingly being used in co-extruded geomembranes for geoenvironmental applications. These thin-films behave differently under different humidity conditions. This study investigated the permeation properties of toluene through two EVOH thin-films (32â¯mol% ethylene and 44â¯mol% ethylene) for both non-aqueous and aqueous solutions. The results of this study are used to gain a better understanding of the behaviour of the EVOH layer used in co-extruded geomembranes. The thin-film results are compared with published values for co-extruded linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) geomembranes with an EVOH core. Permeation coefficients are presented over a range of contaminant concentrations from 25â¯ppm to 99% toluene based on almost five years of continuous testing and the effect of moisture is discussed. A number of EVOH thin-films were affected by humidity (i.e., where moisture diffused into the film) prior to diffusion testing under non-aqueous conditions. This observation led to an investigation of the effect of moisture uptake on the permeation of toluene under non-aqueous testing. In these cases, the 44â¯mol% thin-film had lower toluene permeation coefficient values than the 32â¯mol% thin-film. These values were similar to toluene permeation coefficient values from tests with aqueous solutions. When relative humidity was less than 60%, the 32â¯mol% had slightly lower permeability values than 44â¯mol% thin-film. However, even when affected by humidity, the permeability of both thin-films were considerably (two to three orders of magnitude) lower than previously observed in a water-saturated solution. Permeation of toluene from a 1/1 toluene/hexane solution was also examined for the 32â¯mol% EVOH thin-film at temperatures of 23-50â¯Â°C and results fit well with a conventional Arrhenius relationship of increasing Pg values with increasing temperature.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geotextiles and Geomembranes - Volume 46, Issue 4, August 2018, Pages 529-541
Journal: Geotextiles and Geomembranes - Volume 46, Issue 4, August 2018, Pages 529-541
نویسندگان
Rebecca S. McWatters, R. Kerry Rowe,