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Inferences concerning the amorphous regions in polyethylene of different morphologies
Author(s) -
Dole Malcolm
Publication year - 1975
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760150811
Subject(s) - amorphous solid , crystallinity , solubility , sorption , materials science , endothermic process , quenching (fluorescence) , exothermic reaction , hydrogen , crystallization , chemical engineering , crystallography , analytical chemistry (journal) , thermodynamics , chemistry , organic chemistry , adsorption , composite material , physics , quantum mechanics , engineering , fluorescence
Using a liquid nitrogen quenching method for the measurement of the ppm of hydrogen dissolved in polythylene (PE) at atmospheric pressure, solubility data were obtained for the following types of samples of linear PE: bulk, single crystalline and extended chain. For samples of equal amorphous volume fraction, the hydrogen is about 10‐fold more soluble in single crystalline PE than in bulk. The solubility in extended chain samples becomes more abnormal, the higher the crystallinity. No hydrogen dissolves in a perfect C 20 H 42 crystal. The excessive solubility in the single crystalline samples is interpreted in terms of more sorption sites in the folded part of the chains in the amorphous surface layers than in bulk PE. As the heat of sorption changes from endothermic to slightly exothermic in passing from the bulk to the single crystalline or extended chain samples, the sorption sites must pre‐exist in the latter two types.