When some elementary free volumes in polymers are not seen by positron annihilation experiments

[摘要] Size distributions of elementary free volumes have been studied in mesoporous micro-heterogeneous polymer sorbents. Positron annihilation lifetime spectroscopy (PALS), low temperature gas adsorption (BET) and thermo-stimulated luminescence (TSL) measurements are employed as complementary instruments for the study. It is shown that small admixtures of rubbers are very effective for variations of the pore size distribution. While BET technique was very informative for measurements of mesopores(2-50 nm), positron annihilation was sensitive to micropores(

[发布机构] N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Kosygin st. 4, Moscow; 119991, Russia^1;A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov st. 28, Moscow; 119991, Russia^2;A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii prosp., 31, Moscow; 119071, Russia^3

[效力级别] 化学

[关键词] Diffusion length;Heterogeneous systems;Inhomogeneous distribution;Low temperatures;Measurements of;Micro-heterogeneous;Positron annihilation lifetime spectroscopy;Thermostimulated luminescence