Monitoramento em tempo real da morfologia na extrusão da blenda polimérica polipropileno/ nylon 6.
Abstract
The aim of this work is to assess in real time the morphological
parameters of polypropylene and polyamide 6 blends during the extrusion
process. An optical detector based on the visible light transmitted and extinction
principle was assembled in a slit die located at the exit of a twin screw extruder
in order to get the changes in the polyamide 6 particle concentration and size.
The influence of particle size and concentration was first verified during bench
calibration, where it was observed that the light extinction was greater the
higher the concentration and the lower the particle size. In the case of mixtures
an additional relation concerned to changes in size and density was verified. It
was also stated that the detector records the ponderal average size of a set of
particles. During extrusion experiments, the analyses were performed in the
steady and transient state. In both cases it was verified that normalized signal
intensity increases with increasing particle concentration and decreasing the
dispersed phase size. Infrared analysis and images obtained from scanning
electron microscopy confirmed these results. The correlation between dispersed
phase concentration and size with the detector s normalized signal was
established through the elaboration of regression equations. The plot of
normalized signal as a function of the dispersed phase concentration and size
enabled the calculation of the extinction cross section values for the PP/ PA6
blend.