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Thermal effects in polytetrafluoroethylene at high hydrostatic pressures
Author(s) -
Rodriguez Ernesto L.
Publication year - 1986
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1986.070320321
Subject(s) - thermoelastic damping , thermodynamics , differential scanning calorimetry , polytetrafluoroethylene , atmospheric temperature range , hydrostatic equilibrium , hydrostatic pressure , materials science , thermal , range (aeronautics) , composite material , analytical chemistry (journal) , chemistry , physics , organic chemistry , quantum mechanics
The temperature changes as a result of rapid hydrostatic pressure applications are reported for polytetrafluroethylene (PTFE, Teflon) in the reference temperature range from 294° to 381°K and in the pressure range from 13.8 to 200 MN/m 2 . The thermal effects were found to be higher at the reference temperature approximating the transition temperatures of 19° and 30°C than at higher reference temperature. The data were analyzed by determining the predicted thermoelastic coefficients derived from the Thomson equation (∂ T /∂ P = α T /ρ C p ). A curvefitting analysis showed that the empirical curve, (∂ T /∂ P ) = ab (Δ P ) b−1 , described the experimental thermoelastic coefficients obtained from the experiments. The fact that no agreement was found between the predicted and the experimental coefficients is due to the physical changes in PTFE at the transition temperatures. The relationship between the thermal effects and the chain molecular motion is discussed by including dynamic mechanical analysis and differential scanning calorimetry DSC measurements for the PTFE samples.