Pressure-Dependence of Glass Transition Temperature of Elastomeric Glasses.
RUTGERS - THE STATE UNIV PISCATAWAY NJ HIGH PRESSURE MATERIALS RESEARCH LAB
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Pressure dependence of the glass transition temperature T sub g of two elastomers, Solithane 113 and 3,3-Bisazidomethyloxetanetetrahydrofuran BAMOTHF has been determined, employing high pressure differential thermal analysis HP-DTA and dielectric techniques, up to 8.5 Kbar. The glasses of the elastomers were named the specific or P sub i - glass or the general glass depending on how the glasses were formed. A P sub i - glass was formed by lowering temperature under a constant pressure P sub i and the pressure dependency of the P sub i - glass was determined after changing pressure only in the glassy state. The general glass consists of a series of specific glasses but the T sub g is determined only at pressure under which the glass is formed. The T sub g for both glasses appears to level off at very high pressures while the T sub g does not level off for the general glass. Thermodynamic analysis was made to show that for many general glasses including Solithane, n 1 in dT sub gdp alpha delta1 n delta alpha. It is also shown that variation in several parameters in the Gibbs and DiMarzio theory can be used effectively to predict the observed experimental results. Author