摘要:
A method for carrying out the continuous polymerization of a monomer in a carbon dioxide reaction medium comprises the steps of: (a) providing an apparatus including a continuous reaction vessel and a separator; (b) carrying out a polymerization reaction in the reaction vessel by combining a monomer and a carbon dioxide reaction medium therein (and preferably by also combining an initiator therein), wherein the reaction medium is a liquid or supercritical fluid, and wherein the reaction produces a solid polymer product in the reaction vessel; then (c) withdrawing a continuous effluent stream from the reaction vessel during the polymerization reaction, wherein the effluent stream is maintained as a liquid or supercritical fluid; then (d) passing the continuous effluent stream through the separator and separating the solid polymer therefrom while maintaining at least a portion of the effluent stream as a liquid or supercritical fluid; and then (e) returning at least a portion of the continuous effluent stream to the reaction vessel while maintaining the effluent stream as a liquid or supercritical fluid. The need for significant recompression of the continuous effluent stream prior to return to the reaction vessel is thereby minimized. Apparatus for carrying out such methods is also disclosed.
摘要:
A method for carrying out the continuous polymerization of a monomer in a carbon dioxide reaction medium comprises the steps of: (a) providing an apparatus including a continuous reaction vessel and a separator; (b) carrying out a polymerization reaction in the reaction vessel by combining a monomer and a carbon dioxide reaction medium therein (and preferably by also combining an initiator therein), wherein the reaction medium is a liquid or supercritical fluid, and wherein the reaction produces a solid polymer product in the reaction vessel; then (c) withdrawing a continuous effluent stream from the reaction vessel during the polymerization reaction, wherein the effluent stream is maintained as a liquid or supercritical fluid; then (d) passing the continuous effluent stream through the separator and separating the solid polymer therefrom while maintaining at least a portion of the effluent stream as a liquid or supercritical fluid; and then (e) returning at least a portion of the continuous effluent stream to the reaction vessel while maintaining the effluent stream as a liquid or supercritical fluid. The need for significant recompression of the continuous effluent stream prior to return to the reaction vessel is thereby minimized. Apparatus for carrying out such methods is also disclosed.
摘要:
A method for forming a fluoropolymer comprises providing a reaction mixture comprising carbon dioxide, at least one fluoromonomer, and an initiator; and reacting the at least one fluoromonomer in the reaction mixture to form a fluoropolymer. The fluoropolymer has a multimodal molecular weight distribution.
摘要:
Methods of carrying out a reactive extrusion processes are described that include combining at least one polymer, oligomer, or combination thereof, a carbon dioxide containing fluid, and at least one reactant in an extruder to form a mixture such that the carbon dioxide containing fluid comes into intimate contact with the at least one polymer, oligomer, or combination thereof and assists in a reaction between the at least one polymer, oligomer, or combination thereof and the at least one reactant, and wherein the at least one polymer, oligomer, or combination thereof is modified upon reaction with the at least one reactant.
摘要:
A woven tubular endoprosthesis comprising means for locking the endoprosthesis in a deployed configuration is disclosed. The means for locking the endoprosthesis may comprise locking protrusions, notches, a chemical bond, a curable bond, or other mechanism. The woven fibers comprising the endoprosthesis may be hollow and comprise circumferentially oriented polymeric chains, and may be filled with a curable material. A method of treatment using an endoprosthesis according to the invention is also disclosed.
摘要:
A plurality of artificial red blood cell particles includes each particle of the plurality being substantially monodisperse and each particle having a largest common linear dimension of about 5 μm to about 10 μm. The particles can also have a modulus configured such that a particle of the plurality of particles can pass through a tube having an inner diameter of less than about 3 μm.
摘要:
The use of a photocurable perfluoropolyether (PFPE) material for fabricating a solvent-resistant PFPE-based microfluidic device, methods of flowing a material and performing a chemical reaction in a solvent-resistant PFPE-based microfluidic device, and the solvent-resistant PFPE-based microfluidic devices themselves are described. In an embodiment, a method is described for preparing a patterned layer of a photocured perfluoropolyether, the method comprising: (a) providing a substrate, wherein the substrate comprises a patterned surface; (b) contacting a perfluoropolvether precursor with the patterned surface of the substrate; and (c) photocuring the perfluoropolyether precursor to form a patterned layer of a photocured perfluoropolyether.
摘要:
Methods of making a removable dental positioning appliance include forming a sheet of transparent crystalline polymeric material into a shell having cavities shaped to receive and reposition teeth from a first orientation to a successive orientation. The polymeric material may then be annealed at a temperature above its glass transition temperature or cured if a curable material to enhance characteristics of the polymeric material. The polymeric material may be coated with a second transparent material.
摘要:
A polymer composite includes a polymer and an additive encased in the polymer, wherein the additive includes a plurality of isolated particles where each particle of the plurality of particles has a substantially predetermined three dimensional shape and is substantially oriented with respect to each other in a predetermined two dimensional array.
摘要:
Micro- and nano-particles are molded in micro- and nano-scale molds fabricated from non-wetting, low surface energy polymeric materials. The micro- and nano-particles can include pharmaceutical compositions, biologic drugs, drug compositions, organic materials, RNA, DNA, oligonucleotides, and the like.