In-line LALLS optical detector for probing morphological changes in multiphase polymer systems

Abstract

The knowledge in real time of a multiphase polymer system morphology already during its manufacturing process is a key factor in reducing off-grade material production. This work presents an in-line LALLS prototype to quantify in real time the degree of orientation during production of flat or blow-stretched films and evaluate in-line changes in the melt concentration, morphology and degree of orientation during the extrusion of polymer blends and composites. It quantifies the light scattering intensity as a laser beam crosses a solid or molten multiphase polymer system. The intensity of the non-deflected laser beam provides an indication of the second phase content, the characteristic pattern of the in-line 3D light scattering intensity curve monitors in real time the degree of morphology orientation of molten or solid-state multiphase polymer films and the scattered light intensity pattern gives the average particle size, using a simplified Mie scattering curve.