Aperfeiçoamento de um detector de espalhamento de luz laser em baixo ângulo (LALLS in-line) para acompanhamento em tempo real do processo de extrusão
Resumo
The morphology of extruded multiphase polymer systems is usually
assessed through off-line characterization methods such as microscopy, which
require much time for sample preparation and analysis of the results. This work
aimed to the improvement of an optical detector to measure in real time the
morphology of blends and polymeric composites in processing by extrusion, by
laser light scattering at low angle (LALLS). Such equipment includes hardware
and software and is based on measuring the intensity of light from a laser and is
spread across and under the melt flow. The signals are collected by an array 91
of photodetectors sent to a computer, and displayed in real time on a three-
dimensional plot of scattered light intensity to form a surface defined by 321
points. When analyzing the scattering profile valuable information can be
determined that help to elucidate the morphology of the second phase particles.
The LALLS detector was tested on bench using standard samples, which were
prepared so that one of its parameters (orientation, second phase
concentration, dispersed particle size or type of dispersed particle) were known.
This allowed the systematic study of these samples and the detector device
validation. Finally, the device was tested in real time on the extrusion process,
and under different materials and operating conditions. Thus, the LALLS
detector device created by the group was improved making it possible to
evaluate in a practical way and in real time polymer blends in solid films and
morphology of some blends and polymeric composites during extrusion.