1979results about How to "Narrow molecular weight distribution" patented technology

A novel modified conjugated diene polymer is obtained by polymerizing a conjugated diene compound with a specified catalyst consisting of components (a)-(c) and then reacting with at least one specified compound selected from the group consisting of components (d)-(l), and has a content of cis-1,4-bond of not less than 85% and a ratio of weight average molecular weight to number average molecular weight of not more than 4. And also, a rubber composition comprises the modified conjugated diene polymer a rubber ingredient.

The present invention relates to one kind of high activity catalyst for catalyzing and activating CO2 to react with alkane epoxide to synthesize polycarbonate. The high activity catalyst is tetradentate Schiff base metal complex with double function, i. e., it has both electrophlic center originated from the metal ion in the complex and nucleophilic center originated from the quaternary ammonium salt or quaternary phosphonium salt connected to the benzene ring in the complex. The catalyst can catalyze the reaction of CO2 and alkane epoxide effectively to prepare polycarbonate.

The invention relates to a loaded non-metallocene catalyst and a preparation method and application thereof. The loaded non-metallocene catalyst has the characteristics of simple and practicable preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to the application of the loaded non-metallocene catalyst to the homopolymerisation/copolymerization of olefin. Compared with the prior art, the application has the characteristic of small using amount of a cocatalyst.

The invention relates to a supported non-metallocene catalyst and a preparation method thereof. The supported non-metallocene catalyst is characterized by a simple and practical preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to an application of the supported non-metallocene catalyst in olefin homopolymerization/copolymerization. The application is characterized in that compared with the prior art, the dosage of the catalyst is lower.

Novel catalyst systems for metathesis reactions, in particular for the metathesis of nitrile rubber, which contain a specific salt additive in addition to the metathesis catalyst are provided.

The invention relates to a supported non-metallocene catalyst and its preparation method. The preparation method of the supported non-metallocene catalyst is characterized by simple and convenient preparation method, flexible and adjustable polymerization activity etc. The invention also relates to use of the supported non-metallocene catalyst in homopolymerization/copolymerization of alkenes, and less co-catalysts are required compared with the prior art.

The invention relates to a loaded non-metallocene catalyst and a preparation method and application thereof. The loaded non-metallocene catalyst has the characteristics of simple and practicable preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to the application of the loaded non-metallocene catalyst to the homopolymerisation/copolymerization of olefin. Compared with the prior art, the application has the characteristic of small using amount of a cocatalyst.

The invention relates to a supported non-metallocene catalyst and a preparation method thereof. The supported non-metallocene catalyst has the characteristics of simple and feasible preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to application of the supported non-metallocene catalyst in homopolymerization/ copolymerization of olefins.Compared with the prior art, the consumption of a cocatalyst is low in the application.

The invention relates to a loaded non-metallocene catalyst and a preparation method and application thereof. The loaded non-metallocene catalyst has the characteristics of simple and practicable preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to the application of the loaded non-metallocene catalyst to the homopolymerisation/copolymerization of olefin. Compared with the prior art, the application has the characteristic of small using amount of a cocatalyst.

The invention relates to a loaded non-metallocene catalyst and a preparation method and application thereof. The loaded non-metallocene catalyst has the characteristics of simple and practicable preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to the application of the loaded non-metallocene catalyst to the homopolymerisation/copolymerization of olefin. Compared with the prior art, the application has the characteristic of small using amount of a cocatalyst.

The invention relates to a loaded non-metallocene catalyst and a preparation method and application thereof. The loaded non-metallocene catalyst has the characteristics of simple and practicable preparation method, flexible and adjustable polymerization activity and the like. The invention also relates to the application of the loaded non-metallocene catalyst to the homopolymerisation/copolymerization of olefin. Compared with the prior art, the application has the characteristic of small using amount of a cocatalyst.

The invention relates to a preparation method of a star polycarboxylic acid high-performance water reducing agent. Polybasic alcohol and (methyl) acrylic acid used as main raw materials for esterification are esterified and polymerized to prepare the star polycarboxylic acid high-performance water reducing agent material: the (methyl) acrylic acid and polybasic alcohol used as reactants are esterified under the action of a catalyst to firstly prepare a star polymerizable active terminal, and free-radical polymerization reaction is carried out with unsaturated polyethenoxy ether, molecular weight regulator and unsaturated carboxylic acid monomer under the action of an initiator to prepare the star polycarboxylic acid high-performance water reducing agent. The invention is easy to control, and has the advantages of high polymerization degree, low cost and no pollution; the esterification reaction is carried out form an active core, and the free-radical polymerization is carried out to generate the chain arm, thereby implementing the polycarboxylic acid high-performance water reducing agent in a star molecular structure; and under the condition of common doping amount and low doping amount, the star polycarboxylic acid high-performance water reducing agent has better cement paste flowability and holding capacity than the traditional linear and comb polycarboxylic acid water reducing agents, and has favorable cement adaptability and concrete application performance.

The present invention relates to a method for preparing lactone polymers, carbonate polymers, lactone-carbonate block copolymers and lactone-arbonate random copolymers via a ring-opening addition reaction of a lactone monomer, a cyclic carbonate monomer or a mixture thereof using an initiator and in the presence of a specific titanium-type Lewis acid catalyst. The resulting polymers have a molecular weight distribution (Mw/Mn) approximately equal to 1 or a extremely high purity of single-structure components. The polymer molecules range in an oligomer region to a molecular weight of approximately 200,000. The present invention also relates to a method for preparing lactone polymers, carbonate polymers and lactone-carbonate copolymers having a narrow molecular weight distribution and which can be obtained via a continuous polymerisation of a lactone monomer and/or a cyclic carbonate monomer using an initiator in an extruder in the presence of a specific titanium-type Lewis acid catalyst or an aluminium-type Lewis acid catalyst. The present invention also relates to these resulting polymers.

A vinyl polymer having at least one terminal group of the general formula (1) per molecule;

—OC(O)C(R)═CH₂  (1)

wherein R represents hydrogen or an organic group containing 1 to 20 carbon atoms;

• • a curable composition containing said polymer;
  • an aqueous emulsion containing either said polymer or said curable composition;
  • a pressure sensitive adhesive composition and a pressure sensitive adhesive each comprising said curable composition or aqueous emulsion.

The present invention provides a process for producing a block copolymer in high productivity, by anionic polymerization by use of a lithium initiator, and also to provide the block copolymer and a hydrogenated product thereof, the block copolymer having a conjugated diene block portion with a high vinyl bond content and a vinyl aromatic block portion with a narrow molecular weight distribution and exhibiting a narrow molecular weight distribution and high strength. A conjugated diene monomer and a vinyl aromatic monomer by use of a lithium initiator, are block copolymerized by making a tertiary amine compound and (2) sodium alkoxide coexist, wherein (2)/(1) (a molar ratio)=from 0.01 or more to less than 0.1.

The invention involves a bio-polyol prepared from epoxy rapeseed oil. The preparation method comprises: carrying out ring-opening reaction of epoxy rapeseed oil with an active hydrogen-bearing nucleophilic reagent at the presence of catalyst to obtain the mixed hydroxyl fatty acid triglyceride, and adding alcoholysis agent of alcohols or alkanolamine and heating for alcoholysis reaction to obtain mixed hydroxyl fatty acid monoester, i.e. biological-based polyol. The invention has the advantages of epoxy rapeseed oil being cheap and easy to get or self-design, reduction of dependence on petrochemical products, strong functions and high adjustability, and production of different functionality and pre-designed hydroxyl values of the bio-polyol according to requirements.

The present invention concerns a process for producing homogeneous polyethylene materials and processes for making high density, medium density and low density films therefrom. The process involves producing a polyethylene composition in a multistage reaction sequence of successive polymerization stages in the presence of an ethylene-polymerizing catalyst system. According to the invention, the process is carried out using an unsupported catalyst having magnesium and titanium as active constituents, in at least one loop polymerization stage and at least one gas phase polymerization stage and, operated with different amounts of hydrogen and comonomers to produce a high molecular weight portion in one of the polymerization stages and a low molecular weight portion in another so as to provide a polyethylene composition with the low molecular weight part having a MFR2 of 250 g/10 min or more. With this process it is possible to obtain homogeneous bimodal polyethylene material.

The present invention discloses one kind of terminated non-ionic surfactant and its preparation process and application. The surfactant is allyl terminated polyether with molecular weight controllable in 700-9500 Da, narrow molecular weight distribution and high reaction activity. It has methylol terminating rate up to 95 % and double bond terminating rate up to 93 %, and possesses structure as shown.

The invention provides a block poly-carboxylic acid concrete high-efficiency water reducing agent with an ordered structure and a preparation method thereof. The block poly-carboxylic acid is prepared by using atom transfer radical polymerization, the structural regularity and the molecular weight distribution of the poly-carboxylic acid are controlled effectively, and the water reducing agent is used in a cement dispersing process. By adoption of the block poly-carboxylic acid concrete high-efficiency water reducing agent and the preparation method thereof, the problems of uncontrollable molecular weight of the poly-carboxylic acid, wider molecular weight distribution, un-designable molecular structure and the like are solved.

The invention discloses a method for preparing aliphatic polycarbonates by catalyzing by the metal cyanide coordination catalyst. In a high pressure reactor, the metal cyanide coordination catalyst is utilized to catalyze epoxide and carbon dioxide body or solution copolymerization, wherein, the copolymerization temperature is 20-150 DEG C; the carbon dioxide pressure is 0.5-10MPa; the reaction time is 1-48h; the catalyst concentration is 1-100kg epoxide/g catalyst; the polymerization activity is more than 1.0kg of polymer/g catalyst; the weight-average molecular weight of the copolymer is more than 80 thousand; the molecular weight distribution is 1.5-4; the alternation degree of the copolymer is more than 90%; the cyclic carbonate by-product is less than 5wt%; the CO2 fixed rate of CO2/epoxypropane copolymer is more than 40wt%; and the CO2 fixed rate of CO2/cyclohexene oxide copolymer is more than 30wt%.

The present invention relates to one kind of high molecular weight polybutanediol succinate and its preparation process, and features that bihydroxy terminated butanediol succinate, especially low molecular weight bihydroxy terminated butanediol succinate, as the pre-polymer and diisocyanate as the chain extender in 0.1-13 % are molten and reacted to prepare polybutanediol succinate with low cost, great molecular weight, narrow molecular weight distribution and excellent mechanical performance. The polybutanediol succinate has number average molecular weight greater than 5.5x10<4>, molecular weight distribution of 1.4-1.8, tensile strength of 39-58 MPa, and elongation at break of 300-700 %.