A New In‐line Optical System for Monitoring Residence Time during Polymer Processing Along a Twin‐Screw Extruder

Abstract

Residence time (RT) is an important factor in the processing of molten materials, since it strongly influences the quality of the final product. In this study, a simple and low cost optical system is developed to determine residence time of polypropylene (PP) during its processing in a TeckTrill co‐rotational twin screw extruder. The temperature profile is 90/160/180/190/190/195/195/200/200/210 °C with a screw speed of 300 rpm and a feed rate of 2.3 kg h‐1, using a commercial tracer and different screw profiles. Through the capture of images of the processed material, obtained by a webcam at the matrix output, the developed program is able to calculate the average RGB (red‐green‐blue) color of the analysis area and convert it to the HSV (hue‐saturation‐value), generating a curve of color saturation as a function of time. The results suggest that the developed optical system is a potential suitable tool for in‐line RT measurements.