Abstract:
Nanoporous three-dimensional networks of polyurethane particles, e.g., polyurethane aerogels, and methods of preparation are presented herein. Such nanoporous networks may include polyurethane particles made up of linked polyisocyanate and polyol monomers. In some cases, greater than about 95% of the linkages between the polyisocyanate monomers and the polyol monomers are urethane linkages. To prepare such networks, a mixture including polyisocyanate monomers (e.g., diisocyanates, triisocyanates), polyol monomers (diols, triols), and a solvent is provided. The polyisocyanate and polyol monomers may be aliphatic or aromatic. A polyurethane catalyst is added to the mixture causing formation of linkages between the polyisocyanate monomers and the polyol monomers. Phase separation of particles from the reaction medium can be controlled to enable formation of polyurethane networks with desirable nanomorphologies, specific surface area, and mechanical properties. Various properties of such networks of polyurethane particles (e.g., strength, stiffness, flexibility, thermal conductivity) may be tailored depending on which monomers are provided in the reaction.
Abstract:
The invention relates to a method for producing thin porous membranes made of cross-linkable silicone compositions (S), according to which method an emulsion is formed from the silicone compositions (S) using a pore forming agent (P) in the presence of an emulsifier (E) and optionally solvent (L) in a first step, the emulsion is given a form and the solvent (L), if present, is allowed to evaporate in a second step, the emulsion is cross-linked in a third step, and the pore forming agent (P) is removed from the cross-linked membrane in a fourth step. The invention further relates to membranes that can be produced according to the method and to the use thereof for separating mixtures, in adhesive plasters, as a water-repellent and breathable layer in textiles or as packaging materials.
Abstract:
Aerogel, calcined articles, and crystalline articles comprising ZrO2. Exemplary uses of the crystalline metal oxide articles include dental articles (e.g., restoratives, replacements, inlays, onlays, veneers, full and partial crowns, bridges, implants, implant abutments, copings, anterior fillings, posterior fillings, and cavity liner, and bridge frameworks) and orthodontic appliances (e.g., brackets, buccal tubes, cleats, and buttons).
Abstract:
Provided are porogen compositions and methods of using such porogen compositions in the manufacture of porous materials, for example, porous silicone elastomers. The porogens generally include comprising a core material and shell material different from the core material. The porogens can be used to form a scaffold for making a resulting porous elastomer when the scaffold is removed.
Abstract:
Provided are porogen compositions and methods of using such porogen compositions in the manufacture of porous materials, for example, porous silicone elastomers. The porogens generally include comprising a core material and shell material different from the core material. The porogens can be used to form a scaffold for making a resulting porous elastomer when the scaffold is removed.