An apparatus for measuring the effect of pressure on the time-dependent properties of polymers

We improved and upgraded the apparatus that Fillers, Moonan, and Tschoegl u sed several years ago to investigate the influence of pressure and temperat ure on the mechanical properties of time dependent polymeric materials. The new apparatus can measure the volume and the shear relaxation moduli of so lid polymer specimens, subjected to a combination of temperatures from -60 to + 110 degreesC, and pressures from atmospheric to 360 MPa. The paper dem onstrates the capabilities of the new apparatus from the scientific as well as engineering stand point. Shear relaxation measurements on poly(vinyl ac etate) (PVAc), natural rubber, styrene-butadiene rubber, and ethylene-propy lene-diene-monomer rubber are also presented. For PVAc we present also bulk creep compliance, coefficient of thermal expansion, and the bulk modulus. (C) 2001 The Society of Rheology.