High‐pressure differential thermal analysis/dilatometric apparatus based on an Instron capillary rheometer

摘要: A high‐pressure apparatus in the form of a modified Instron capillary rheometer capable measuring differential thermal analysis (DTA) data and pressure–volume–temperature (P–V–T) relations was constructed our laboratory. Temperatures from 20 to 370 °C pressures 1 6000 bar are achievable with data‐acquisition control system based on an APPLE II+ microcomputer. Measurements pressure accuracy 1%, temperature 0.5%, volume change 0.1% have been obtained. Software developed operate experiments at fixed heating or cooling rates as well constant isothermal sweeps. Polymer samples were compressed into rods preceding experiment by vacuum molder eliminate voids. Low‐density polyethylene (LDPE) run example demonstrate performance this apparatus. The results revealed excellent match between experimental published data.