abstract statement of the problem: dental prosthesis is usually made indirectly; therefore dimensional stability of the impression material is very important. every few years, new impression materials with different manufacturers’ claims regarding their better properties are introduced to the dental markets which require more research to evaluate their true dimensional changes. objectives: the ...

We describe the synthesis of water-soluble semiconductor nanoparticles and discuss and characterize their properties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embedded in a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFM indicates that the siloxane shell is 1-5 nm thick, yielding final particle size...

Heat treatment is a standard method to increase the hardness of silica in various applications. Here, we tested the effect of high temperature annealing on the mechanical properties of silica microcapsules by force spectroscopy under point loads applied to the particle shell. The Young's modulus of the shells moderately increases after annealing at temperatures above 500 °C. Temperatures over 8...

Title of Dissertation: DEVELOPMENT OF ARYL SILOXANE CROSSCOUPLING TECHNOLOGY AND ITS APPLICATION TO THE SYNTHESIS OF COLCHICINE AND ALLOCOLCHICINE DERIVATIVES William Michael Seganish, Doctor of Philosophy, 2005 Dissertation directed by: Professor Philip DeShong Department of Chemistry and Biochemistry One of the most versatile methods for the formation of aryl-aryl bonds is the palladium-catal...

Create three-dimensional network of siloxane polymer in the epoxy resin is an appropriate mechanical properties .Dispersion of nanoclay in these coating was prepared by ultrasonication method. Mechanical properties of nanocomposit coatings such as abrasion, hardness and adhesion was increased by addition of nanoclay montmorillonite. Different percentages of nanoclay in coating showed that even ...

New biodegradable network polymers containing siloxane-linked polymeric prodrugs of 5-ammino-2-hydroxybenzoic acid (5-ASA) in the main chain were prepared by ter polymerization of methacrylic acid (MA), 2-hydroxyethylmethacrylate (HEMA), and bis (trimethylsilyloxy) methylsilane (VBM) in the presence of some new cross-linking agents.The monomers and polymers were characterized by FT-IR and 1H-NM...

A new decomposition method for structural analysis of polysiloxanes (silicones) was developed using methyl orthoformate. The siloxane bonds in samples with vinyl and/or methyl side groups decomposed under relatively mild acidic conditions up to around 70°C and were followed by methoxylation at the cleaved linkages with few side reactions. The product yields with respect to the siloxane monomer ...

Optimization of performance of holographic gratings was investigated by changing the chemical structures of photopolymerizable monomers, the LC content, and recording beam intensity, which strongly related to the control of kinetics of polymerization and phase separation of LCs. High diffraction efficiency was obtained using 3-acryloxypropyltrimethoxysilane (APTMS) and 2-[(3,4-epoxycyclohexyl)e...

Soreanu, G., M. Béland, P. Falletta, K. Edmonson, L. Svoboda, M. Al-Jamal and P. Seto. 2011. Approaches concerning siloxane removal from biogas * A review. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada. 53: 8.1 8.18. One of the major barriers to the use of biogas as an alternative renewable energy source is the presence of siloxanes. At combustion temperatures, siloxanes ar...