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 present invention relates to a process for the processing of perfluoropolymer materials, and to the use of the resultant products in different potential applications, such as in the medical device field.
Abstract:
An aerogel includes a plurality of supramolecular structures bound to one another. Each supramolecular structure includes a carbon nanotube (CNT) or graphene type structure having an outer surface, and a plurality of polymers or aromatic molecules secured to the outer surface of the CNT or graphene type structure. The plurality of polymers or aromatic molecules have at least one crosslinkable structure. The supramolecular structures are crosslinked together by chemical bonding between the crosslinkable structures. The polymers can be block copolymers including at least one conjugated polymer block and at least one block of a crosslinkable non-conjugated polymer that provides the cross linkable structure, where the conjugated polymer block is non-covalently bonded to the outer surface of the CNT or graphene type structure.
Abstract:
A process for forming voided latex particles is improved by combining swelling and polymerization of an outer shell into a single step. The process includes contacting multi-stage emulsion polymer particles comprising a core, at least one intermediate shell, with a swelling agent, and polymerizing an outer shell after said contacting with swelling agent wherein the core and the at least one intermediate shell are contacted with swelling agent in the presence of less than 0.5% monomer based on the weight of the multi-stage emulsion polymer particles, and substantially all of the swelling occurs during polymerization of the outer shell.
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:
Polymeric composite particles are provided that can be used for the storage and delivery of various biologically active agent. The polymeric composite particles contain a porous polymeric core and a coating layer around the porous polymeric core. The porous polymeric composite particles typically further include a biologically active agent positioned within the porous polymeric core but not covalently bonded to the porous polymeric core. The biologically active agent can be released from the polymeric composite particle by diffusing out of the porous polymeric core through the coating layer.
Abstract:
Porous polymeric particles are provided that can be hydrophilic or hydrophobic. The porous polymeric particles can be used for the storage and delivery of various active agents or for moisture management. Reaction mixtures for forming the porous polymeric particles, methods of making the porous polymeric particles, and articles containing the porous polymeric particles are also provided.
Abstract:
A method of forming aerogels includes mixing a plurality of polymers or aromatic molecules, a solvent, and a plurality of carbon nanotubes (CNTs) or graphene including structures to form a mixture, where the polymers or aromatic molecules have at least one crosslinkable structure. A solid gel is formed including a plurality of supramolecular structures from the mixture. The plurality of supramolecular structures include a plurality of the polymers or aromatic molecules secured by π-π bonds to the outer surface of the CNTs or graphene including structures. The solid gel includes a portion of the solvent trapped therein. The plurality of supramolecular structures are crosslinked and then dried to remove the solvent trapped therein to form the aerogel.
Abstract:
A method for producing a porous polymer structure involves (i) forming a polymer; (ii) subsequently contacting the polymer with a nonsolvent and inducing the formation of an emulsion in which the nonsolvent is present as the dispersed phase and the polymer as the continuous phase; and (iii) removing at least some of the nonsolvent so as to leave pores within the polymer, wherein the polymer is formed by exciting one or more molecules in an exciting medium, in particular by pulsed plasma deposition. Emulsion formation in step (ii) may be induced by or in the presence of an emulsion stabilising agent. Also provided is a porous polymer structure produced using the method, and a polymer which is impregnated with an emulsion stabilising agent, for use in the emulsion formation step of the method.
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).