In-Line Monitoring of Vinyl Chloride Suspension Polymerization with Near-Infrared Spectroscopy, 1 - Analysis of Morphological Properties (original) (raw)
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2009
This article introduces the use of in-line and in situ monitoring of the dynamic evolution of PVC morphological properties in suspension polymerization reactions based on near infrared spectroscopy (NIRS) intended for control applications. It is shown for the first time that it is possible to follow the dynamic evolution of morphological properties (such as the bulk density, BD, and the cold plasticizer absorption, CPA) in real time. The obtained results indicate that closed-loop control schemes can be properly implemented to control end-use resin properties, which depend upon the morphology of PVC polymer particles. Suspension polymerization of vinyl chloride performed in bench and pilot scale showed that process variables, such as the agitation speed and the amount of suspending agents) can be successfully manipulated in order to control the morphological parameters of PVC resin. Based on this information, a control scheme for these parameters is proposed.
2009
The monitoring of polymer properties is frequently performed through sampling and off-line measurement of quality parameters in lab scale. Because of the long time required to perform off-line analyses, off-line data are generally inadequate for control purposes. As impurities cannot be detected in-line and can exert significant influence on the polymerization kinetics, modifications of some important quality parameters (such as the morphological characteristics of PVC particles) can only be detected at the end of the polymerization, causing major production losses. In the present work it is shown for the first time that it is possible to monitor some of the morphological properties of PVC (such as the bulk density, BD, the cold plasticizer absorption, CPA, and the average particle diameter Dp) in situ and in real time with the help of near infrared spectroscopy (NIRS) in suspension polymerization processes.
Use of Online Spectroscopy to Control Polymerization in Industrial Processes
Macromolecular Reaction Engineering, 2017
Online analyzers enable manufacturers to operate modern polymerization processes as safely, reliably, and profitably as possible. The most critical application of this technology involves monitoring the reactor itself to determine the molecular weight and comonomer content of the polymer produced. Polymer process streams introduce unique challenges for online analyzers because the process chemistry, sample transport, and stream conditions are harsher, prone to fouling, and pose unique safety hazards. Spectroscopy lends itself very well to online analysis of polymers because the data it provides is information rich and can be deployed using fiber optics for remote sampling of gases, liquids, and solids. Additionally, it is relatively fast and reliable if well designed and installed properly. The combination of spectroscopy, fiber optics, and chemometrics gives manufacturers the ability to use modern spectrometers and statistical models to analyze and monitor diverse types of polymeri...