A series of polyurethane polymers was synthesized with increasing proportions of silicone in the form of polydimethylsiloxane (PDMS) utilised as a cross-linking agent, based on an aromatic, non-biostable polyetherurethane (PEtU). Eight formulations ranging from 0-50% PDMS were constructed into porous and non-porous films. These were implanted subcutaneously in rats, both unstrained and 100% str...

-Montmoril lonites saturated with small quaternary alkylammonium ions such as tetramethylammonium (TMA) or trimethylphenylammonium (TMPA) are excellent sorbents for aromatic pollutants. In some cases, water inhibits arene sorption, but the inhibition mechanism is not understood completely. The objectives of this study were to determine whether arenes interact with adsorbed TMA and TMPA ions and...

OBJECTIVE To determine the effect of different retraction cord medicaments on surface detail reproduction of polyvinyl siloxane impression materials and compare this effect on any two brands of commercially available polyvinyl siloxane impression materials. MATERIAL AND METHODS Four stainless steel dies were made according to ADA specification no.19. Three dies were treated with aluminium chl...

Palladium-catalyzed cross-coupling of phenyl, vinyl, and allyl siloxane derivatives proceeded in good to excellent yield with aryl iodides, electron-deficient aryl bromides, and allylic benzoates. Methyl and 2,2,2-trifluoroethyl siloxane derivatives can be employed in the coupling reaction. Electron-donating and -withdrawing groups are tolerated on the aryl halide without affecting the coupling...

AB S TRACT: Montmorillonites ion-exchanged with Li +, Na +, K § Ca 2+, Mg 2+ and Ni 2+ and acidic clay were used as catalysts for the polymerization of a cyclic siloxane monomer, 2,4,6,8tetramethylcyclotetrasiloxane. Montmorillonites with Ni 2+ and Mg 2+ in the interlayer, and acidic clay exhibit a greater ability for siloxane polymerization in both yield and mean molecular weight of products t...

Activated carbon filters are used to limit engine damage by siloxanes when biogas is utilised to provide electricity. However, carbon filter siloxane removal performance is poorly understood as until recently, it had not been possible to measure siloxanes on-line. In this study, on-line Fourier Transform Infrared (FTIR) spectroscopy was developed to measure siloxane concentration in real biogas...

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...

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...