Living olefin polymerization processes
AssigneeMassachusetts Institute of Technology
InventorsRichard R. Schrock, Robert Baumann
Life of this patent
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Abstract
Processes for the living polymerization of olefin monomers with terminal carbon-carbon double bonds are disclosed. The processes employ initiators that include a metal atom and a ligand having two group 15 atoms and a group 16 atom or three group 15 atoms. The ligand is bonded to the metal atom through two anionic or covalent bonds and a dative bond. The initiators are particularly stable under reaction conditions in the absence of olefin monomer. The processes provide polymers having low polydispersities, especially block copolymers having low polydispersities. It is an additional advantage of these processes that, during block copolymer synthesis, a relatively small amount of homopolymer is formed.
Claims48
A composition of matter having a structure:
- R.sub.1 --X--A--Z--R.sub.2 !.sup.2.sup.-
- wherein X and Z are each group 15 atoms, R.sub.1 and R.sub.2 are each a hydrogen atom or group 14 atom-containing species and A is selected from the group consisting of ##STR5## wherein Y.sub.1 is a group 16 atom, Y.sub.2 is a group 15 atom, R.sub.3 is H or a group 14 atom-containing species and L.sub.1 and L.sub.2 are each dative interconnections including at least one group 14 atom bonded to Y.sub.1 or Y.sub.2.
A method of synthesizing a block copolymer, the method comprising:
- performing a first reaction including exposing a first monomeric species containing a terminal carbon-carbon double bond to an initiator containing a metal and allowing terminal carbon-carbon double bonds of the first monomeric species to insert successively into the initiator to form a metal-carbon bond thereby forming a first homopolymeric block of the first monomeric species connected by a bond to the metal of the initiator;
- and
- performing a second reaction including exposing a second monomeric species containing a terminal carbon-carbon double bond to the initiator and allowing terminal carbon-carbon double bonds of the second monomeric species to insert successively into the initiator, first inserting into the bond between the block of the first homopolymeric block and the metal of the initiator, thereby forming a copolymer including the first homopolymeric block bonded to a second homopolymeric block of the second monomeric species, the copolymer having a polydispersity of no more than about 1.4.
A method of synthesizing a block copolymer, the method comprising:
- exposing a first monomeric species having a terminal carbon-carbon double bond to an initiator including a metal and allowing terminal carbon-carbon double bonds of the first species to insert successively into the initiator to form a metal-carbon bond thereby forming a first homopolymeric block of the first monomeric species having a bond to the metal of the initiator;
- and
- exposing a second monomeric species containing a terminal carbon-carbon double bond to the initiator and allowing terminal carbon-carbon double bonds of the second species to insert successively into the initiator, first inserting into the bond between the first homopolymeric block and the metal, thereby forming a copolymer including the first homopolymeric block connected to a second homopolymeric block of the second monomeric species, the method producing no more than about 25% by weight of the first homopolymer or the second homopolymer relative to a total amount of polymer product.
A block copolymer, comprising:
- a first homopolymeric block comprising a polymerization product of at least about ten units of a first monomeric species having a formula H.sub.2 C.dbd.CHR.sub.1 ;
- and
- a second homopolymeric block comprising a polymerization product of at least about ten units of a second, different monomeric species having a formula H.sub.2 C.dbd.CHR.sub.2, the second homopolymeric block being connected to the first homopolymeric block,
- wherein R.sub.1 and R.sub.2 can be the same or different and each are H or a linear, branched, or cyclic hydrocarbon that is free of non-carbon heteroatoms, and wherein the block copolymer has a polydispersity of at most about 1.4.
A method of polymerization, the method comprising:
- reacting an initiator having a metal atom with a monomeric species having a terminal carbon-carbon double bond to allow terminal carbon-carbon double bonds of monomers to insert successively into the initiator to form a metal-capped polymer of the monomeric species connected to the metal through a metal-carbon bond, the metal-capped polymer being stable, in a solvert essentially free of the monomeric species and electron donors comprising water and free oxygen at a temperature of at least about -50.degree. C., and capable of then reacting further with monomeric species and inserting the monomeric species successively into a metal carbon bond.
Dependencies are inferred from the claim text.