Tham khảo tài liệu 'thermodynamics interaction studies solids, liquids and gases part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 650 Thermodynamics - Interaction Studies - Solids Liquids and Gases importance of dissociating the purely hydrostatic effect from the fluid sorption over an extended pressure range. Taking advantage of the differential mounting of the high pressure calorimetric detector and the proper use of the thermodynamic Maxwell s relation ỔS ÕP T - ỔV ÕT p a practical expression of the global cubic expansion coefficient O pol-g-int of the saturated polymer subjected to the compressed penetrating permeant solvent under isothermal conditions has been established as follows by eq. 7 Qđiff SS - Qdiff pol VSS r aSST AP apol-g-int Vpol T AP aSS is the cubic expansion coefficient of the stainless steel of which are made the cells. Vpol and VSS are the volumes of the polymer sample placed in the measuring cell and of the stainless steel reference sample placed in the reference cell respectively. The stainless steel sample is identical in volume to the initial polymer sample. Qdiff pol is the differential heat between the measuring cell and the reference cell. Qf SS is the measure of the thermodynamic asymmetry of the cells. AP is the variation of gas-pressure during a scan at constant temperature T. Three quite different pressure transmitting fluids as regards their impact on a given polymer have been selected i mercury Hg inert fluid with well-established thermomechanical coefficients inducing exclusively hydrostatic effect ii a non-polar medium nitrogen N2 qualified as poor solvent and iii chemically active carbon dioxide CO2 Glasser 2002 Nalawade et al. 2006 . While maintaining the temperature constant the independent thermodynamic variables p or V can be scanned. Optimization and reliability of the results are verified by applying fast variations of pressure P jumps pressure scans P scans and volume scans V scans during pressurization and depressurization. Additionally taking advantage of the differential arrangement of the calorimetric detector the comparative behaviour of two .
