11 results about "Tacticity" patented technology

Provided are a metallocene compound and a preparation method therefor and a use thereof. The metallocene compound is a bridged Cs-symmetric large-conjugated-coordination metallocene compound, exhibiting high catalytic activity, and polypropylene produced by a catalytic reaction exhibits high tacticity.

A composition comprising a C2-C12 polyalphaolefin and a functionalized propylene-based elastomer comprising from about 4 to about 25 wt % units derived from one or more C2 or C4-C12 alpha-olefins; a triad tacticity greater than about 90%; a heat of fusion less than about 75 J / g; and a plurality of oxygen containing functional groups selected from carboxylic acids, anhydrides, ketones, carbonates, esters, ethers, lactones, and combinations thereof. Compositions containing the functionalized propylene-based elastomer and methods to produce the same are also disclosed.

The application relates to the technical field of polyester fibers, and discloses a preparation method of high-strength and high-modulus polyester fibers and the polyester fibers, which comprises the following steps: (1) mixing 4,4'-diphenyldicarboxylic acid, 1,3-propanediol, a catalyst and a thermal stabilizer to perform esterification; (2) after the esterification is completed, first-stage polycondensation reaction is performed, and then second-stage polycondensation reaction is performed, small molecules and water are removed during the reaction, and a polymer is obtained; (3) the polymer is subjected to melt spinning, and then sequentially passes through first-stage side blowing, second-stage side blowing and post-stretching to obtain polyester fibers. The PET melt is prepared through esterification and polycondensation reaction of 4,4'-diphenyldicarboxylic acid monomers and 1,3-propanediol monomers, the relative molecular mass can be increased, the stereoregularity of the macromolecular chain can be increased, and finally, the polyester fibers with high breaking strength, elastic modulus and melting point can be prepared through melt spinning.

The present disclosure relates, in part, to catalyst compounds and methods of use thereof for stereocontrolled living radical polymerization. In another aspect, the present disclosure relates to isotactic polymers and / or polymers having controlled tacticity, and applications thereof. In certain embodiments, the isotactic polymers and / or controlled tacticity polymers are prepared according to the methods of the present disclosure.

A bicomponent fiber comprising a sheath, where the sheath includes a propylene-based elastomer, said propylene-based elastomer including propylene-derived units and from about 3.0 to about 15 wt % alpha-olefin-derived units other than propylene-derived units, based upon the entire weight of the copolymer, said propylene-based elastomer having a triad tacticity of greater than 75%, and a heat of fusion, as determined by DSC, of less than 75 J / g; and a core, where the melt temperature of the core, as determined by DSC, is at least 5% greater than the melt temperature of the sheath.

The invention relates to the technical field of polymer synthesis and functional materials, in particular to polyvinyl butyral resin as well as a preparation method and application thereof. Through a continuous flow reaction method, reaction parameters are precisely controlled to realize extreme uniformity of a reaction microenvironment, and a specific catalytic system is further combined to realize precise'customization 'of the microstructure of the polyvinyl butyral resin, so that the stereoregularity of the polyvinyl butyral resin is stabilized in a better and narrower'gold' range, and the stability of the polyvinyl butyral resin is improved. The isotactic proportion is 8-10 mol%, the isotactic proportion is 3.5-4.5 mol%, and the beneficial stereoregularity is better. By utilizing the excellent mixing, heat transfer and residence time control capabilities of the continuous flow reaction method, the defects of extensive control of the tacticity of the stereotacticity and poor repeatability of the traditional batch method are overcome, excellent batch repeatability is obtained, and the standard deviation between batches is reduced from more than 1 mol% to less than 0.3 mol%.

The present invention relates to a catalyst component and a catalyst system for olefin polymerization and applications thereof, the catalyst component contains a magnesium element, halogen, a titanium element, a regulator a and an internal electron donor compound b, the regulator a is at least one of 1, 2-diether compounds represented by formula (I-1) and formula (I-2), and the internal electron donor compound b is at least one of 1, 2-diether compounds represented by formula (I-1) and formula (I-2). The internal electron donor compound b is a dihydric alcohol ester compound as shown in a formula (II), and the catalyst component can keep relatively high activity and can be used for producing the catalyst component which has the characteristics that the crystallinity is reduced and the steric regularity is easy to adjust; the method can be used for developing a polymer which has the characteristics that the crystallinity is reduced, the content of xylene soluble substances and isotactic indexes are easy to adjust and the like by changing the dosage of an external electron donor while the adjustable range of the stereotactic capability is enlarged.

The present invention relates to a catalyst component and a catalyst system for olefin polymerization and applications thereof, the catalyst component contains a magnesium element, halogen, a titanium element, a regulator a and an internal electron donor compound b, the regulator a is at least one of 1, 2-diether compounds represented by formula (I-1) and formula (I-2), and the internal electron donor compound b is at least one of 1, 2-diether compounds represented by formula (I-1) and formula (I-2). The internal electron donor compound b is a diether compound as shown in a formula (II), and the catalyst component and the catalyst system can maintain relatively high activity and can be used for producing a polymer which has the characteristics of reduced crystallinity and easily adjusted stereoregularity.

The invention relates to a rare earth complex with a simple structure, a catalyst composition and application, and belongs to the technical field of polymer preparation. The structure of the rare earth complex is shown as a general formula (I), and in the general formula (I), Ln is Sc, Y, La, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm or Lu; in the formula (I), R1 is selected from halogen, silyl groups of C1 to C10, aralkyl groups of C7 to C15, silamido groups of C1 to C10 or allyl groups of C3 to C10; l is tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1, 4-dioxane, ethylene glycol dimethyl ether, thiophane, tetramethylethylenediamine or pyridine; n = 0, 1 or 2. A catalytic polymerization system containing the rare earth complex provided by the invention has the following characteristics that the rare earth complex serving as a catalyst is simple in structure, convenient to prepare and high in polymerization yield, and a polymer prepared by catalyzing olefin has high stereoregularity. ; (I)

The invention relates to the technical field of polymer synthesis, and discloses a chiral zinc-based catalyst and a preparation method and application thereof.The preparation method comprises the steps that a phenylenediamine derivative and a halogenated carboxylic acid compound are taken to react, and a halogenated benzimidazole derivative is obtained; carrying out nucleophilic substitution reaction on the halogenated benzimidazole derivative and an aminophenol compound in an organic solvent to obtain a tridentate ligand; the tridentate ligand and a zinc source compound are subjected to a complexation reaction in an organic solvent to obtain the chiral zinc-based catalyst. The chiral zinc-based catalyst has a tridentate chiral active center with an adjustable coordination environment, and can induce the monomer to be inserted in a specific stereoregularity mode in the ring-opening polymerization process of the lactone monomer, so that the stereoregularity of the polyhydroxyalkanoate is improved; according to the invention, on the premise of ensuring high monomer conversion rate, collaborative regulation of polymer molecular weight and molecular weight distribution is realized, and preparation of polyhydroxyalkanoate with high molecular weight, narrow molecular weight distribution and high stereoregularity is facilitated.

The present disclosure generally relates to polymer blends containing polypropylene copolymers and roofing membranes thereof. In some embodiments, a composition includes a polypropylene copolymer including about 0.1 mol% to about 35 mole% ethylene units and about 99.9 mol% to about 65 mole% propylene units. The polypropylene copolymer has an mm triad tacticity of about 75% or greater, regio defects of about 0.01 mol% to about 1.2 mol%, an r1r2 of about 0.8 to about 3, a melt flow rate (230 °C / 2.16 kg) of about 4 g / 10 minutes or less, a phase angle at 10 kPa at 190 °C less than 69 degrees, and an [EEE] triad content of about 0.5 mol% to about 4 mol%. The composition includes an impact copolymer. The composition optionally includes a plastomer.