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Online monitoring of polymerization reactions is not only important due to the high exothermic nature of most polymerization systems; the data gained also provides information on product composition and quality and control possibilities thereof. Many inline and online methods are still in development and are better suited for application on the laboratory or pilot-plant scale. Industrial polymerization plant environments pose additional technical and financial challenges and constraints for the use of such systems. Available methods and current developments are reviewed with regard to their practicability and usefulness under these aspects.

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Radical polymerizations in emulsion, suspension and solution are very important industrial production processes. To be able to control these processes to achieve good product quality makes the development of methods to observe these reactions in situ a very important topic not just in academia, but also in industry. In this paper, the advantages and disadvantages of different methods to follow emulsion and suspension polymerization reactions as well as spray drying processes are discussed from an industrial point of view. Calorimetry, near infrared spectroscopy and Raman spectroscopy are the methods with the highest potential for on-line applications. Droplet formation in spray drying can be observed by laser light scattering methods. Spectroscopic methods have used data analysis methods (principal component analysis, partial least squares) for a number of years. These methods can also be used as ''soft sensors'' Downloaded by [McGill University Library] at 07:24 07 February 2015 with standard process data. Examples how these soft sensors can be applied to emulsion polymerization processes are shown.

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The high solids semicontinuous emulsion polymerization of VAc and VeoVa10 using poly­(vinyl alcohol) (PVOH) as polymeric stabilizer is investigated. It is shown that (i) PVOH strongly affects the kinetics of the process and (ii) the formation of PVOH-graft-poly­(VAc–co-VeoVa10) leads to an overestimation of the gel content and an underestimation of the sol molecular weight when the standard characterization techniques are directly applied. A new method to properly characterize the MWD of these copolymers is presented. A mathematical model is used to analyze the effects of surfactant and initiator on the kinetics and polymer microstructure.

The physical aspects of the clouding phenomenon in the aqueous solution of a poly(oxyethylene)(POE) – poly(oxypropylene)(POP) – poly(oxyethylene)(POE) triblock copolymer were investigated by applying various experimental methods: viscometry, ultrasonic technique, light scattering, infrared and Raman spectroscopy. The ultrasonic absorption studies hint at a critical behaviour. In order to understand the spectroscopic findings, conformational energies of model POE molecules as well as interaction energies between oxyethylene (OE) units and water molecules were calculated by the use of the quantum chemical PCILO method. It is suggested that the clouding is connected with conformational changes of POE segments.