Controlled radical polymerization processes
AssigneeCarnegie Mellon University
InventorsYungwan Kwak, Renaud Nicolay, Krzysztof Matyjaszewski
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Abstract
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.
Claims11
A transition metal mediated controlled chain transfer agent polymerization process comprising polymerizing radically (co)polymerizable monomer(s) by a controlled chain transfer agent polymerization process in the presence of:
- an initiator comprising substituted dithio-groups selected from the group consisting of dithioesters, dithiobenzoates, dithiocarbamates, trithiocarbonates and xanthates, substituted with various alkyl substituents;
- a transition metal compound;
- and
- a ligand;
- wherein the resulting (co)polymer has a polydispersity of less than 1.5;
- and
- wherein the initiator comprising substituted dithio-groups are formed by reaction of one of a dithioester disulfide, a dithiobenzoate disulfide, a dithiocarbamate disulfide, a trithiocarbonate, and a xanthate disulfide in the presence of:
- an alkyl halide, optionally comprising functional groups;
- a transition metal catalyst;
- and
- a ligand.
A transition metal mediated controlled chain transfer agent polymerization process comprising polymerizing radically (co)polymerizable monomer(s) by a controlled chain transfer agent polymerization process in the presence of:
- an initiator comprising substituted dithio-groups selected from the group consisting of dithioesters, dithiobenzoates, dithiocarbamates, trithiocarbonates and xanthates, substituted with various alkyl substituents;
- a transition metal compound;
- and
- a ligand;
- wherein the resulting (co)polymer has a polydispersity of less than 1.5;
- and
- wherein the initiator comprising substituted dithio-groups additionally comprises one or more different radically transferable atoms or groups.
A process for the preparation of a chain transfer agent or initiator containing a dithio-group selected from dithiobenzoate, dithiocarbamate, and xanthate with various alkyl substituents comprising:
- conducting a transition metal mediated addition fragmentation reaction with one of a bis(thiobenzoyl) disulfide, a bis(ethylxanthogen) and a tetraethylthiuram disulfide in the presence of an alkyl halide and about 0.05 equivalents of a transition metal catalyst complex capable of a conducting an activation/deactivation reaction.
A controlled polymerization process comprising polymerizing radically copolymerizable monomers in the presence of:
- a dithio-chain transfer agent;
- a transition metal compound;
- a ligand that forms a soluble complex with the transition metal compound;
- and
- a reducing agent
- wherein the final copolymer has a degree of polymerization greater than 1,000 and a polydispersity less than 1.5.
Dependencies are inferred from the claim text.