51results about How to "Improve polymerization conversion rate" patented technology

This invention involves unsaturated cyclic aliphatic carbonate monomer and polymer synthesis and uses, and is biomedical polymer materials. From 2,2 - dimethylolpropionic acid departing, to synthesize 2-methyl-2-allyl-oxygen carbonyl trimethylene carbonate and 2-methyl-2-propargyl oxygen carbonyl trimethylene carbonate, and then through ring-opening polymerization or aliphatic monomers cycloate monomer opening loop and copolymerization, gain copolymer of aliphatic polycarbonate or aliphatic polyester-carbonate that side group contains double and Triple bond. Such polymer has advantage of both aliphatic polyester and carbonate, is biodegradable, degradation products is non-toxic. Use the functional side group of Double and Triple bond can connect drugs, active peptides or other bioactive elements with the polymer, improving the biocompatibility and biological activity of polymer, which may has real application in controlled-release drug, polymer pro-drug and tissue engineering fields.

The invention relates to acetophenone type photoinitiators using fluorene as a conjugated structure as well as a preparation method and an application of the acetophenone type photoinitiators. According to the photoinitiators, substituted acetophenone with high electron-attracting capability is taken as an electron-attracting group, and fluorene molecules with different lengths are taken as the conjugated structure and form a D-pi-A type molecule system with electron-donating triphenylamine groups. Two types of Type II photoinitiators are provided according to different conjugated structures and different acetophenone substituted positions. The synthesis steps of the photoinitiators are simple, purification is easy, the yield is high, the light absorption property is good, the photoinitiators are easy to dissolve in a monomer, the absorption peak of the photoinitiators ranges from 365 nm to 405 nm, and the photoinitiators can initiate free radical and cationic polymerization under the initiation of ultraviolet and visible light and has a faster initiation speed and very high polymerization conversion rate. Two types of photoinitiators have wide application in the field of UV photocuring.

The invention relates to a method for continuously preparing optical-grade polymethyl methacrylate. The method comprises the following steps of: continuously supplying (meth)acrylate monomer or the solution containing not more than 5% of inert solvent into a circulating tube type reactor for polymerization, wherein the polymerization temperature is controlled within the range of 130-160 DEG C and the polymer content is controlled within the range of 40-65%; continuously sending the reaction material into a heater for further polymerization, wherein the polymerization temperature is set within the range of 140-170 DEG C, and the content of the polymer is increased to 55-80%; sending the obtained reaction mixture into a devolatilization extruder to continuously remove a volatile substance by separation, wherein the ratio of material circulation rate to feeding rate inside the circulating tube type reactor is controlled within the range of 40:1-120:1. A highly-pervious pure polymethyl methacrylate molding compound product can be stably prepared by adopting the method provided by the invention.

The invention relates to a di-oxime ester photoinitiator having high light sensitivity in a near ultraviolet-visible light zone as well as a preparation method and an application thereof. The di-oxime ester photoinitiator is the nonionic and halogen-free photoinitiator which is effective in the ultraviolet-visible light zone of 365 nm-425 nm, an oxime esters group having strong electron-withdrawing capability is taken as an electron-withdrawing group, and forms a conjugated system with thiophene through connection, and the di-oxime ester photoinitiator has a disubstituted symmetrical structure. The photoinitiator has excellent performaces of storage stability, sensitivity, development performance and pattern integrity, compared with the same kind photoinitiator, the preparation method in the invention is simple, the applicable light source scope is wide, and the toxicity is low; disubstituted characteristic on the structure of the photoinitiator increases the acid generation performance by several times, and compared with the current single oxime esters photoinitiator products, the performance of the photoinitiator is better.

The present invention relates to a method for preparing a diene-based rubber latex having improved impact strength, gloss and flexibility, diene-based rubber latex prepared therefrom, and an acrylonitrile-butadiene-styrene graft copolymer having improved impact strength and production yield while having reduced rubber solid content ratio by comprising the same.

The invention discloses a fluorine-containing acrylate copolymer synthesis method. The fluorine-containing acrylate copolymer synthesis method comprises the following steps of: obtaining mixed monomer miniemulsion of (perfluorooctyl) ethyl acrylate, n-butyl methacrylate and methylmethacrylate by taking methacryloyloxyethyl trimethyl ammonium chloride (DMC) as a cation emulsifying agent and cetane as co-stabilizer according to a mini-emulsification technology, and carrying out miniemulsion copolymerization under the initiation action of AIBN (2,2-azobisisobutyronitrile) to obtain miniemulsion of a fluorine-containing acrylate copolymer. The fluorine-containing acrylate copolymer has the beneficial effects that the fluorine-containing acrylate copolymer has a relatively high fluorine-containing monomer conversion rate; the cost is reduced; the utilization rate of a fluorine-containing monomer is effectively increased; and after polymerization is ended, an emulsifying agent can be removed by a simple and convenient demulsification precipitation method to obtain the fluorine-containing copolymer product with the relatively high purity, so that the copolymer has relatively good water and oil repellency and antifouling property.

The invention discloses a synthesizing method for acrylate copolymers with hydrophobicity. A small amount of compound emulgator and co-stabilizer is used for making acrylate monomers form uniform andstable miniemulsion. A miniemulsion polymerization method is adopted for obtaining acrylate copolymer emulsion, and after polymerization is finished, through a separation technology of demulsificationcohesion and many-time dissolution-sediment circulating operation, the acrylate copolymer with hydrophobicity is obtained. No obvious emulgator residues are contained in the obtained copolymer, the purity and hydrophobicity performance of the acrylate copolymers with hydrophobicity are improved, the using amount of fluorine-containing monomers is reduced, and the cost is reduced; a polymerizationsite of miniemulsion polymerization is oily monomer drops, it is avoided that in the conventional emulsion polymerization process, acrylate monomers need to be diffused to solubilizing micelles through an aqueous phase, the polymerization conversion rate of the fluorine-containing acrylate monomers with hydrophobicity is effectively improved, the discharging amount of fluorine-containing monomersis reduced, and environmental pollution is reduced. The synthesizing method has a good application prospect in the field of water-proof antifouling paint.

The present invention relates to a method for preparing a diene-based rubber polymer having a relatively low gel content and a high swelling index while having a high polymerization conversion ratio, to a diene-based rubber polymer prepared thereby, and to a core-shell structured acrylonitrile-butadiene-styrene graft copolymer comprising the diene-based rubber polymer as a core. The method for preparing a diene-based rubber polymer and the core-shell structured acrylonitrile-butadiene-styrene graft copolymer comprising the diene-based rubber polymer prepared by the method can be easily applied in an industry in need thereof, especially, an industry of an impact modifier.

The invention discloses a high-temperature-resistant polyacrylate composition and a preparation method thereof. The high-temperature-resistant polyacrylate composition is a copolymer of an acrylic monomer and a carboxylic acid cross-linking monomer. The preparation method comprises the following steps: adding a raw material, namely the acrylic monomer, a raw material, namely the carboxylic acid cross-linking monomer, and a conditioning agent into an emulsifier solution, and in the presence of nitrogen for protection, initializing a copolymerization reaction through free radicals; after the copolymerization reaction is completed, adding a reducing agent for aftertreatment; finally, adding a polycoagulant for demulsification, bleaching with clean water, and dehydrating, thereby obtaining a composition product. Thermogravimetic analysis shows that the initial thermogravimetic weight of the high-temperature-resistant polyacrylate composition is 235-240 DEG C, and the high-temperature-resistant polyacrylate composition can be used for a long time under a condition within 190 DEG C; in addition, no extra heat exchange means are taken in the preparation method of the high-temperature-resistant polyacrylate composition, the temperature rise of a reaction system is within 20 DEG C, the polymerization conversion rate is as high as 98-99%, conditions are gentle, and industrial application conditions can be completely met.

The invention provides a preparation method of a methyl methacrylate polymer. The preparation method comprises the following steps: intermittently adding polymerization feed liquid into a reactor, andcarrying out intermittent polymerization reaction, wherein the polymerization feed liquid comprises a first polymerization monomer and a first initiator; and continuously adding a mixture of a polymeric monomer feed liquid and an initiator feed liquid into the reactor, and carrying out a continuous polymerization reaction to obtain the methyl methacrylate polymer, the polymeric monomer feed liquid comprising a second polymeric monomer, and the initiator feed liquid comprising a third polymeric monomer and a second initiator. The preparation method can realize stable operation of bulk polymerization; according to the present invention, the high polymerization conversion rate of 45-75% can be obtained at the low polymerization temperature by using the low addition amount of the initiator, the polymerization residence time is shortened to 120-150 min, the production efficiency is improved, the generation of the dimer is reduced, the content of the dimer in the polymer is less than 1%, and the high-purity polymer is obtained.

The invention discloses a caprolactone-tung oil copolymerized polyol polymer and a synthesis method thereof, and belongs to the field of macromolecular synthesis. According to the method, a mass polymerization one-step method is adopted, low molecular weight tung oil polyol prepared from diethanol amine and tung oil by aminolysis reaction and caprolactone are used as polymerizing monomers, and stannous octoate is used as a polymerization catalyst, and the caprolactone-tung oil copolymerized polyol polymer of which the molecular weight is 0.2*10<4> to 1.1*10<4> is synthesized by changing the molar ratio of the caprolactone to the tung oil under protection of an inert gas (N2) at the temperature of 150-170 DEG C. The caprolactone-tung oil copolymerized polyol polymer can be used as a novel polyester to be widely applied to preparation of polymers and copolymers.

The invention relates to a preparation method of a polymer for a polyacrylonitrile-based carbon fiber precursor without metal ions in a polymerization system, which comprises the following steps: mixing monomer acrylonitrile, a second polymerization monomer, a third polymerization monomer and deionized water, heating and keeping at 45-65 DEG C, stirring at 100 rpm, respectively dropwise adding a water-soluble initiator into a reactor at the same titration rate at the same time, and reacting at the temperature of 45-65 DEG C for 2-3 hours; after dropwise adding the initiator, reacting for 30 to 120 minutes; removing residual monomers, washing and drying to obtain polyacrylonitrile powder; wherein in terms of the mass of all the polymerization monomers, the monomer acrylonitrile accounts for 92-99 wt%, the feeding amount of the second copolymerization monomer accounts for 1-7.0 wt%, the feeding amount of the third copolymerization monomer accounts for 0.1-3.0 wt%, and the use amount of the initiator accounts for 0.1-2.0 wt%; and an initiator. The method has the advantages of fast polymerization reaction speed, low reaction temperature, high polymerization conversion rate and low production cost. As the polymerization system does not contain metal ions, the polyacrylonitrile-based carbon fiber precursor with high purification and high quality can be obtained, and further the carbon fiber with high performance can be obtained.