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Novel Shear-Thinning of Aged PDMS/Fumed Silica Admixtures and Properties of Related Silicone Elastomers

Fumed silica filler has long been used to structurally reinforce silicone elastomers. Unfortunately, the combination of as little as a few weight percent of untreated fumed silica nanoparticles [uFSN] with a siloxane polymer, such as PDMS, forms a difficult to process waxy solid admixture that even long periods of high shear mixing will not thin. In the course of the current work it was noted that after a period of storage certain solid admixtures would become viscous liquids when subjected to additional high shear mixing. It was further found that the required aging period could be decreased if the admixture storage temperature were increased. The only known interaction of PDMS and uFSN at moderate conditions is the adsorption of polymer on filler, and this interaction is also known to occur more quickly at higher temperature. This study examines the relationship between polymer adsorption and admixture liquefaction. Further, the mechanical properties of cured elastomers containing liquefied admixtures are examined to assess the degree of reinforcement that these materials afford.

Identiferoai:union.ndltd.org:vcu.edu/oai:scholarscompass.vcu.edu:etd-1442
Date29 November 2012
CreatorsBrooke-Devlin, Wayne
PublisherVCU Scholars Compass
Source SetsVirginia Commonwealth University
Detected LanguageEnglish
Typetext
Formatapplication/pdf
SourceTheses and Dissertations
Rights© The Author

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