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Optimization of Expancel Product and Process: Through the use of Multivariate Planning, Data Analysis and Evaluation.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
2012 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The company Expancel produces expandable microspheres. The microspheres are microscopic spherical particles that consist of a polymer shell encapsulating a gas (the blowing agent). Heat causes the particles to expand. The microspheres have many application areas; they are used as additives in for example thermoplastics, coatings, civil explosives, paper and board. The microspheres are produced through a method called suspension polymerization. In suspension polymerization the starting material for the spheres (monomers, initiator and blowing agent) is through vigorous stirring split into small droplets in a surrounding water phase. Polymerization (initiated by heating the emulsion) occurs inside the microscopic droplets, the monomers react to form the polymer shell with the blowing agent captured inside. After the polymerization the product can be filtered and dried.

This degree project consisted of two parts. In the first (and major) part the consequences of replacing a chemical used in the production of the microspheres with a more environmentally friendly alternative was examined. The goal was to produce microspheres with an alternative chemical without changing the properties of the microspheres. First five different alternative chemicals were examined in a selected production recipe in 50 ml scale. The software MODDE was used for design of these experiments and analysis of results. Then the best alternative of the five was examined in three other recipes in 50 ml scale. One of the recipes was also examined in 1 liter scale. Several of the alternative chemicals showed good results in the first recipe, but one of them showed more stable results than the others and was selected to proceed with in the other recipes. The conclusion from the experiments with this chemical was that the amount added affected the particle size, and that best results were achieved when adding the chemical before the flocculation step in the process.

The objective of the second part was to study and evaluate a production process in order to find optimization possibilities. The chosen process was the filtering of the produced microsphere slurry for a specific recipe. Data were collected from the polymerization process, the dewatering process and the characterization analyses performed on the produced microsphere slurry. Production rate was used as response variable. The multivariate analysis software package SIMCA-P+12.0.1 was then used to analyze the data. The conclusion of the multivariate data analysis was that two factors were the most important for explaining the variation in the response variable; the particle size and a polymerization parameter called level.

Place, publisher, year, edition, pages
2012. , 27 p.
National Category
Chemical Process Engineering
URN: urn:nbn:se:umu:diva-56963OAI: diva2:538758
External cooperation
Educational program
Master of Science in Engineering Chemistry
Physics, Chemistry, Mathematics
Available from: 2012-07-02 Created: 2012-07-02 Last updated: 2012-07-02Bibliographically approved

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