摘要:
A new polymerization process (atom transfer radical polymerization, or ATRP) based on a redox reaction between a transition metal (e.g., Cu(I)/Cu(II), provides "living" or controlled radical polymerization of styrene, (meth)acrylates, and other radically polymerizable monomers. Using various simple organic halides as model halogen atom transfer precursors (initiators) and transition metal complexes as a model halogen atom transfer promoters (catalysts), a "living" radical polymerization affords (co)polymers having the predetermined number average molecular weight by .DELTA.�M!/�I!.sub.0 (up to M.sub.n >10.sup.5) and a surprisingly narrow molecular weight distribution (M.sub.w /M.sub.n), as low as 1.15. The participation of free radical intermediates in ATRP is supported by end-group analysis and stereochemistry of the polymerization. In addition, polymers with various topologies (e.g., block, random, star, graft, hyperbranched, dendritic end-functional and in-chain functional copolymers �for example, of styrene and methyl (meth)acrylate!) have been synthesized using the present process. The Polymeric products encompassed by the present invention can be widely used as plastics, elastomers, adhesives, emulsifiers, thermoplastic elastomers, etc.
摘要:
Polyphosphazenes are produced by polymerizing a silylated phosphinimine in the presence of an initiator, preferably an anionic initiator at temperatures below those typically necessary for such polymerization reactions. The polyphosphazenes obtained are suitable for use in the production of elastomeric and thermoplastic materials.
摘要:
A process for constructing multi-arm star macromolecules with uniform properties, high molecular weight and narrow molecular weight distribution using free radical polymerization is described.
摘要:
A transition metal mediated chain transfer agent controlled polymerization process is described. The process combines the advantages of atom transfer radical polymerization (ATRP) and reversible addition fragmentation transfer (RAFT) polymerization. Synthesis of chain transfer agents useful in the disclosed processes is also disclosed. Other improvements on ATRP RAFT processes are also described.
摘要:
The present invention relates to nanostructured bioconjugates and nano-structured network hydrogels used to deliver nucleic acids to targeted biological locations. The present invention further relates to methods of treating clinical conditions using the nanostructured bioconjugates and nano-structured network hydrogels.
摘要:
A process for constructing multi-arm star macromolecules with uniform properties, high molecular weight and narrow molecular weight distribution using free radical polymerization is described.
摘要:
Polymerization processes of the present invention comprise low catalyst concentration. Embodiments include a polymerization process comprising polymerizing free radically (co)polymerizable monomers in a polymerization medium comprising one or more radically (co)polymerizable monomers, a transition metal catalyst complex capable of participating in a one electron redox reaction with an ATRP initiator; a free radical initiator; and an ATRP initiator; (wherein the concentration of transition metal catalyst complex in the polymerization medium is less than 100 ppm). Further embodiments include a polymerization process, comprising polymerizing one or more radically (co)polymerizable monomers in the presence of at least one transition metal catalyst complex; an ATRP initiator; and a reducing agent; wherein the transition metal catalyst complex is present at less than 10−3 mole compared to the moles of radically transferable atoms or groups present on the ATRP initiator.
摘要:
The process of the present invention is directed toward conducting highly selective, high yield post polymerization reactions on polymers to prepare functionalized polymers. An embodiment of the present invention comprises conducting click chemistry reactions on polymers. Preferably, the polymers were prepared by controlled polymerization processes. Therefore, embodiments of the present invention comprise processes for the preparation of polymers comprising conducting a click chemistry reaction on a functional group attached to a polymer, wherein the polymer has a molecular weight distribution of less than 2.0. The functional polymers may be prepared by converting an attached functional unit on the polymer thereby providing site specific functional materials, site specific functional materials comprising additional functionality, or chain extended functional materials.Embodiments of the process of the present invention include functionalization reactions, chain extensions reactions, to form block copolymer linking reactions, and attaching side chains to form graft copolymers, for example.
摘要:
This present invention is directed towards the identification or design, preparation, and use of suitable transition metal complexes for use as catalysts. The transition metal complexes may comprise heterodonor ligands. The present invention is also directed toward a method of determining the suitability of a transition metal complex for use in a catalytic reaction, such as, but not limited to, atom transfer radical polymerization (“ATRP”), atom transfer radical addition (“ATRA”), atom transfer radical cyclization (“ATRC”), and other catalytic redox reactions. The method assists in the approximate determination of the fundamental properties of the transition metal complex in a reaction media, such as, but not limited to, solubility, redox potential, stability towards acidic, basic, or ionic species, conditional radically transferable atom phylicity, and propensity toward disproportionation and therefore, the suitability of the complex to be used as a catalyst in the reaction media. The method provides a basis for prediction and evaluation of the properties of a transition metal complex for a particular selective catalytic reaction in a broad range of reaction environments. An understanding of the principles of the disclosed method allows a transition metal complex to be tuned to specific reaction medium by selecting a transition metal complex and ligand combination having the desired qualities.
摘要:
Disclosed is a process for the removal and recycle of a supported transition metal catalyst complex from a polymerization reaction medium comprising the steps separating the supported transition metal catalyst from the reaction medium and contacting the supported transition metal catalyst with a reducing agent. The reducing agent may be a transition metal and/or a source of radicals. Also disclosed is a process for the recovery of transition metal catalyst from a reaction medium, comprising changing the conditions of a medium comprising transition metal catalyst attached to a solid support, wherein changing the conditions causes desorption of the transition metal catalyst from solid support.