A Gas-Sensor-Based Measurement Setup for Inline Quality and Process Control in Polymer Extrusion

We report on a gas-sensor-based measurement setup for the detection of volatile degradation products directly in the extrusion process. In contrast to available measurement tools, the system is located in the air flow and works independently of the polymer melt flow. Therefore, the sensor can be used also for non-transparent melts with different colors and filler contents. For process validation, the measurement setup was tested offline using selected organic solvents, as well as directly in the extrusion process using talc-filled polypropylene compounds. We show that the amount of lubricants, the shear load, as well as the temperature and the back pressure influence the level of low molecular weight volatile compounds (LMWVOC) and finally the gas-sensor value.