RESUMO
We introduce a hydrophilic monosaccharide-containing 2-(α-D-mannopyranosyloxy)ethyl methacrylate (ManEMA) in this study to achieve more extended and comfortable wear silicone hydrogel contact lenses by increasing water content. Molecular structure of ManEMA contains a monosaccharide moiety with four hydroxyl groups, which provide a strong interaction with water. Therefore, the ManEMA-containing hydrogels are expected to have high water content. The structure of synthesized ManEMA is confirmed by 1H and 13C NMR spectroscopy. Contact lenses containing silicone polymers are coated with a monosaccharide-containingManEMA monomer with the help of plasma treatment and the use of 3-(trimethoxylsilyl)propyl methacrylate to provide an increased hydrophilicity. The feasibility of ManEMA as a surface modifier of silicone lenses is investigated in terms of water content and surface energy.
RESUMO
Porous silicone composites containing different types and volume fractions of hollow silica particles (HSPs) were prepared and characterized in terms of thermal insulation performance, thermal stability, and tensile and dynamic mechanical properties. The comparative study on measured and theoretical thermal conductivity of porous silicone/HSP composites was performed. Dependence of shell thickness, defined as the ratio (η) of internal (ri) to outer (r0) radius, and volume fraction (Φ) of HSPs on the thermal insulation performance of composites was predicted theoretically by Felske model. Tensile properties and dynamic mechanical measurements showed the incorporation of HSPs led to mechanical reinforcement in the silicone composites. Theh Guth and Gold equation showed mechanical reinforcement of porous silicone/HSP composites was primarily due to the hydrodynamic effect of HSPs in the silicone matrix at low HSP contents (Φ < 0.5).
