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Viscosity of polystyrene near the glass transition

1969; Wiley; Volume: 13; Issue: 11 Linguagem: Inglês

10.1002/app.1969.070131116

1097-4628

Richard C. Penwell, Roger S. Porter,

Polymer crystallization and properties

Abstract A quantitative explanation is given for the apparent viscosity increase with increasing capillary shear rate for polystyrene at temperatures approaching the glass transition, T g . Possible shifts in T g as a function of the parameters shear rate, frequency, and pressure are interrelated to viscosity changes. Experimentally, the Instron capillary rheometer and the Weissenberg rheogoniometer provided a means for uncoupling the variables for individual consideration. Calculated and experimental data for the apparent viscosity as a function of the given parameters are presented and discussed. The explanation of the apparent viscosity increase in capillary flow can be quantitatively explained through the pressure dependence of T g . Brief mention is made of the pressure effects on the Bagley and Rabinowitsch corrections normally made in capillary measurements.