PVT measurement system for wood plastic composite melt in an extrusion process

An innovative experimental system is proposed to measure the pressure-specific volume-temperature (PVT) properties of wood-plastic composite (WPC) melt in an extrusion process. The system is based on determining the specific volume by measuring the volume flow rate and mass flow rate of the WPC melt flowing in a capillary die attached to an extruder at each temperature and pressure. The capillary die mounted on an extruder is used to measure the volume flow rate of the melt. The volume flow rate is estimated indirectly by measuring pressure drop through the capillary die and the flow relation for composite melt. The temperature of molten materials was precisely controlled using the stabilizer part mounted on an extruder before the capillary die. The pressure was controlled by the rotational speed of the screw and feed rate of extruder. The mass flow rate was measured by directly collecting and weighing the extruded melt in a specified time. The results show that the rotary shear rheometry experiments integrated with the capillary die in an extrusion process can be used as an economical and quick method for PVT measurement. The wood plastic composite (WPC) consists of high density polyethylene (HDPE) and wood flour powder.