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Effect of sub‐ T g annealing on CO 2 sorption in polycarbonate
Author(s) -
Chan A. H.,
Paul D. R.
Publication year - 1980
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.760200115
Subject(s) - sorption , materials science , enthalpy , langmuir , polycarbonate , annealing (glass) , thermodynamics , heat capacity , thermal diffusivity , analytical chemistry (journal) , adsorption , chemistry , organic chemistry , composite material , physics
High pressure CO 2 sorption data in polycarbonate (PC) are reported as a function of temperature and thermal history. The bulk physical structural changes produced by annealing at 125 and 135°C were monitored by density and thermal property changes. The sorption data are analyzed by the dual sorption model which assumes the sorption isotherm to consist of Henry's law and Langmuir sorption terms; The Langmuir capacity term C H ′of PC can be grossly correlated with the reported volumetric parameters of the polymer. This excess volume interpretation of C H ′has found support in the good correlation between C H ′and the corresponding enthalpy relaxation from parallel Differential Thermal Analysis of the samples. Density measurements provide gross evidence of the free volume interpretation of C H ′ . The experimental uncertainties in the data compromise a more critical test of the relationship between C H ′and the density of annealed samples.