Detection Of Dispersion For Minor Component In Polymer By Fluorescent Tracer Technology

Polymer blending has replaced the synthesis of new polymer to become the most important preparation method of high performance polymer materials. The mixing directly affects the structure and morphology of polymer blend, thereby influencing its physical and chemical properties. The flow, reaction and dispersion during polymer melting processing are occurring at multi-scale factors of the polymer chain structure, multi-phase interface, and shear and tensile complex flow, and often need to add some difficult detectable minor components such as compatibilizer and modifier to improve the properties of the resulting polymer blend. Therefore, for preparing high performance polymer blend, it is very necessary to understand deeply this blending process, particularly the dispersion of minor component in the polymer.This thesis designed and synthesized a macromolecular fluorescent tracer PS-MAMA, and then investigated its dispersion behavior in compatible polystyrene (PS) and incompatible polymethyl methacrylate (PMMA) in a homemade batch mixer from multi-parameters such as mixing time, mixing efficiency, dispersion index and flow filed characteristics obtained by using three methods including in-line fluorescence detector, off-line ultraviolet detector, and numerical simulation. The main research results are as follows:(1) Comparing the dispersion of minors PS-MAMA in PS under square-wave mixing and steady mixing mode, it can be known that the mixing index in the former is 1.67 times higher than that in latter, which may result from their different flow field. The shear flow as the dominated flow of steady mixing mode can form the stable laminar flow in a shorter time but the mixing between the layers is slow; while the flow of square-wave mixing mode is based on the tensile and shear.(2) For the compatible system, increasing rotor’s shear strength can greatly speed up the mixing process around rotors zone, but as to the zones far away from rotors, it performs little effects. In addition, though higher temperature can enhance the mixing of the zone close to the rotors, but it also weaken the the zones far away from rotors.(3) As for the immiscible system, the tensile deformation and fragmentation of minors PS-MAMA can be greatly accelerated by elongation flow provided by square-wave mixing. So the square-wave mixing performs high mixing capacity compared to the steady mixing which mostly provides shear flow. Besides, shear strength of the rotors plays a more important role in the mixing of immiscible polymer blends compared to compatible blends.