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Investigation of Capillary Suspension Drying Behavior with Simultaneous Stress and Weight Measurements

Fischer, Steffen Benno

Abstract (englisch):

Coatings and ceramic green bodies usually contain polymeric additives to prevent cracking caused by drying induced stresses, which requires subsequent removal steps. A new coating formulation using capillary suspensions was found to reduce cracking, while being absent of polymeric additives. This dissertation investigates the drying behavior of capillary suspensions. The cantilever deflection method, commonly used for investigation of drying stresses, is significantly improved. The simultaneous stress and weight measurement technique of the same coating in a temperature and humidity controlled chamber developed in this dissertation is unprecedented. Enhanced by visual observation and coating profiling, we propose liquid flow considerations to explain the observed prolonged constant drying period. Stress measurements performed at different drying conditions and suspension formulations show a decrease in peak stress by up to 40\% for the capillary suspension over the regular suspension without polymeric additives. A complex interplay between yield stress, capillary suspension formulation, and humidity that is capable of reducing the peak stress of a regular suspension is revealed. ... mehr

Volltext §
DOI: 10.5445/IR/1000135339
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Mechanische Verfahrenstechnik und Mechanik (MVM)
Publikationstyp Hochschulschrift
Publikationsdatum 19.07.2021
Sprache Englisch
Identifikator KITopen-ID: 1000135339
Verlag Karlsruher Institut für Technologie (KIT)
Umfang xxxi, 144 S.
Art der Arbeit Dissertation
Fakultät Fakultät für Chemieingenieurwesen und Verfahrenstechnik (CIW)
Institut Institut für Mechanische Verfahrenstechnik und Mechanik (MVM)
Prüfungsdatum 29.06.2021
Schlagwörter Simultaneous stress measurement, cantilever deflection method, film drying, thin films, capillary suspension, capillary bridge, yield stress, particle induced phase separation, partial solubility, miscibility gap, shelf-life, film defects, uniform film, lateral drying, shrinkage, corner flow, particle coatings
Referent/Betreuer Koos, E.
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