Abstract
We succeeded to measure Poisson's ratio of polymeric materials under high pressure and high temperature. We measured Young's modulus and Poisson's ratio of polymethylmethacryrate and polycarbonate under various pressure up to 70MPa with varying temperature. For the measurement, we developed a novel apparatus; we combined a PVT test system with a ultrasonic velocity measurement system. We measured sound velocities of longitudinal and transverse wave propagated through the materials, and we obtained Young's modulus and Poisson's ratio from the velocities. The results under normal pressure were consistent with those obtained by conventional methods.