192 results about "Living polymerization" patented technology

Disclosed are olefin polymerization methods comprising the use of the following compounds:wherein M is a metal atom, R1-R8 are univalent radicals, X1 and X2 are univalent ligands, X3 is a divalent ligand, and (RnY-T) is an optional donor or non-donor group. The relatively stable and simply synthesized pre-catalyst is activated by a co-catalyst under mild reaction conditions, producing exceptionally reactive polymerization of a wide variety of alpha-olefin monomers, and forming a variety of poly(alpha-olefin) products, having high molecular weight and low molecular weight distribution (PDIs close to 1). Living polymerization is performed at or above room temperature, along with achieving block co-polymerization of alpha-olefin monomers at room temperature, and producing polymers and oligomers having a wide range of molecular weights. The catalyst formed during reaction remains "alive' for as long as 31 hours, for producing a polymer with a molecular weight as high as 450,000 grams / mole.

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.

A diene rubber (A) having a weight average molecular weight (Mw) of 100,000 to 3,000,000, an Mw / number average molecular weight (Mn) ratio of 1.30 to 2.50, and an Mw / peak top molecular weight (Mp) ratio 0.70 to 1.30. A rubber composition comprising the diene rubber (A) and a diene rubber (B) having an Mw of 2,000 to 90,0000 and / or an oil extender for rubber has good processability and can give a rubber vulcanizate having high tensile strength and good abrasion resistance. The diene rubber (A) is produced by conducting a living polymerization of diene monomer in a hydrocarbon solvent; adding a polymerization stopper to a polymerization mixture at a conversion of 5 to 98% to deactivate 10 to 90% by mole of active terminals present as of the initiation of polymerization; and finally adding a polymerization stopper to completely terminate the polymerization reaction.

The invention discloses a method for preparing a carbon-coated lithium titanate negative electrode material for a lithium battery. The method comprises the following steps: preparing a polymer with controllable molecular weight by adopting living polymerization, performing ball milling and mixing with raw materials of lithium titanate, and sintering to obtain a lithium titanate material coated with a conductive carbon layer. The adopted polymerization method has the advantages that range of optional monomers is wide, polymers of different carbon chain lengths can be obtained by adjusting the raw material ratio, the carbon chain length distribution is uniform, and the finally obtained carbon-coated lithium titanate material is uniform and stable in performance. Moreover, the initial charge specific capacity of the obtained lithium titanate material reaches over 160mAh / g under the rate of 1C (1C=175mA / g), and the capacity is kept over 90 percent due to cycle of 800 times.

The invention discloses a comb type polymeric dispersant and a preparation method and application thereof. The structural formula of the polymeric dispersant is defined in the specification. The preparation method comprises the steps that the RAFT living polymerization technology is adopted, dodecane sulfenyl sulfo-carbonyl sulfenyl propionic acid serves as a chain transfer agent, azodiisobutyronitrile serves as an initiator, and the comb type polymeric dispersant is obtained through graft copolymerization between unsaturated monomers. According to the application, the dispersant is applied to a spreading oil system, methyl oleate and other environment-friendly solvents are adopted as an organic carrier, an oil-dispersible system is obtained through a wet sanding process, a dispersing agent is added, and spreading oil of different conventional processes is obtained. According to the structure of the comb type polymeric dispersant, polyoxyethylene ether, benzene rings, carboxylic acid groups and other group repetitive units are contained, multipoint adsorption is achieved in the wet sanding process, the dispersant has good compatibility with an oil phase, the lubricating function among particles is improved, the collision probability among the particles is reduced through a macromolecular main chain steric hindrance, and sanding efficiency is improved.

A living polymerization process for preparation of poly(vinyl chloride) (PVC) with controlled molecular weight and molecular weight distribution is described. The polymerization reaction can be initiated by various polyhalocarbon initiators in conjunction with non-metallic reducing single electron transfer reagents as catalysts and accelerated by electron shuttles. The process occurs at room temperature in water or water-organic solvent medium. The polymerization provides PVC with a controlled molecular weight and narrow molecular weight distribution. The halogen containing polymer compositions are useful as, among others, viscosity modifiers, impact modifiers and compatibilizers.

A molecular memory cell and methods for forming a molecular memory cell, which allow for easy and inexpensive manufacturing and flexibility in memory system design. Embodiments include a non-volatile molecular memory cell, comprising: a substrate having a conductor, a superionic conductor, a polymer layer over said superionic conductor, a layer of metal ions formed from the superionic conductor and residing between said polymer layer and said superionic conductor, and a second conductor over the polymer layer. Other embodiments include methods for forming a molecular memory cell, wherein a superionic conductor is deposited over a suitable substrate having conductor. A polymeric film is then deposited over the superionic conductor via a living polymerization reaction initiated by the superionic conductor. Furthermore, a layer of excess metal ions from the superionic conductor forms on an upper surface of the superionic conductor. A top conductor is then formed on the polymeric film.