37results about How to "The degree of cross-linking is controllable" patented technology

The invention discloses an organosilicon insulating impregnating varnish and a preparation method thereof. The organosilicon insulating impregnating varnish comprises a component A and a component B in a weight ratio of 1:1, wherein the component A comprises 100 parts of polymethylphenylvinylsiloxane and 0.9-1.5 parts of platinum catalyst and the component B comprises 30-75 parts of polyhedral oligomeric silsesquioxane with ethylene group and 40-60 parts of hyperbranched polysiloxane with Si-H bond. The polymethylphenylvinylsiloxane synthesized in the preparation method of the invention adoptsethanol as solvent and is no non-toxic and non-harmful; when the prepared impregnating varnish is solidified, no by-product with low molecular weight is discharged, thus not affecting the electric performance of the insulating material; in addition the impregnating varnish has good post impregnation effect, high temperature resistance and environmental friend.

The invention provides a preparation method of a backbone liquid crystal elastomer. A prepolymer is made from the silicon hydrogen addition reaction with the materials of diene monomer containing mesogenic units, polysiloxane containing hydrogen and silane coupling agent under the function of catalyst, then the prepolymer is fabricated into a low crosslinked density network structure containing mesogenic units connects through the hydrolysis of siloxane, finally the liquid crystal elastomer is acquired through suitable stretching. The method is characterized by simple operation, being difficult to be gel, and easy control for elastomer crosslinked density, etc.

The invention discloses a process for preparing composite sulfonated membranes with IPN structures, which is characterized by utilizing dehydration cross-linking agent to lead IPN structures between two polymers to prepare polymers with IPN structures, obtaining IPN composite sulfonated proton exchange membranes through a solvent casting method, adjusting mole ratio of sulfonate and non-sulfonate through sulfonated dihalides, non-sulfonated dihalides and compounds containing dyhydroxyl, or changing structures of the sulfonated dihalides, the non-sulfonated dihalides and the compounds containing dyhydroxyl, and obtaining different types of straight-chain sulfonated compounds via polymerization reaction. The different types of straight-chain sulfonated compounds form proton polymers via proton exchange, and IPN composite sulfonated polymer membranes can be obtained by the proton polymers via high-temperature casting treatment under action of the dehydration cross-linking agent. The process is simple in synthetic process and controllable in sulfonation degree and cross-linking degree, and does not have problems of component separation caused by other compound methods.

The present invention is for crosslinked membranes and in particular for crosslinked poly(ethylene oxide)-cellulose acetate-silsesquioxane (PEO-CA-Si) organic-inorganic hybrid membranes and their use in gas separation. These crosslinked PEO-CA-Si membranes were prepared by in-situ sol-gel co-condensation of crosslinkable PEO-organotrialkoxysilane and CA-organotrialkoxysilane polymers in the presence of acetic acid catalyst during the formation of membranes. The crosslinkable PEO- and CA-organotrialkoxysilane polymers were synthesized via the reaction between the hydroxyl groups on PEO (or on CA) and the isocyanate on organotrialkoxysilane to form urethane linkages under mild conditions. The crosslinked PEO-CA-Si membranes exhibited both increased selectivity of CO₂/N₂ and CO₂ permeability as compared to a CA membrane, suggesting that these membranes are very promising for gas separations such as CO₂/N₂ separation.

A hemostatic composition comprises calcium alginate, a chitosan, epsilon-aminocaproic acid, an acid selected from aminomethylbenzoic acid and tranexamic acid, and tannin. The method of making the hemostatic composition comprises mixing one or more polysaccharide bases, tannin, a fibrinolytic inhibitor, colloidal silver and a solvent to form a mixture, and drying the mixture at a temperature between 25° C. and 80° C. until residual moisture content is approximately 15 to 20%.

The invention discloses a method for cross-linking and modifying medical-grade reconstructed collagen, which is characterized in that 1 to 5 weight parts of phosphate solution with the concentration of 0.1 mol/L to 0.5mol/L is added into 5 to 25 weight parts of uniform regular collagen solution with the concentration of 5 mg/ml to 10mg/ml at the temperature of 15 DEG C to 20 DEG C while slowly stirring. Acid solution or aqueous alkali is used for adjusting the pH value of the mixed solution to 7.0 to 8.5. The mixed solution stands for 6 hours to 12 hours at the temperature of 25 DEG C to 40 DEG C and humidity of 50 percent to 70 percent so as to form uniform colloid. The colloid is sequentially arranged in the environment of minus 20 DEG C to minus 40 DEG C and minus 60 DEG C to minus 80 DEG C to be frozen for 24 hours to 48 hours, and then dehydrated in a lyophilizer to obtain the reconstructed collagen with cross-linked and modified ions.

The invention discloses a nano fiber artificial blood vessel for catalyzing and releasing nitric oxide and a preparation method. The artificial blood vessel consists of a three-dimensional reticular non-woven film pipe structure formed by an inner layer and an outer layer of nano fibers. The artificial blood vessel is prepared by the following method comprising the following steps of: dissolving gelatin in glacial acetic acid to prepare a solution; adding a sodium heparin aqueous solution to prepare a spinning dope for electrostatic spinning to form nano fiber non-woven film pipes; dissolving polyurethane and nantokite chelate in a mixed solution of tetrahydrofuran and N,N-dimethyl fomamide to prepare a polyurethane spinning dope; carrying out electrostatic spinning to continue collecting polyurethane fibers on a collecting roller with the nano fiber non-woven film pipes so as to form polyurethane fiber non-woven film pipes; and soaking and treating the polyurethane fiber non-woven film pipes in an aqueous solution of a crosslinking agent. The artificial blood vessel can catalyze and release nitric oxide for a long time in vivo and in vitro and is beneficial to inhibiting the aggregation of platelets. The preparation method is simple, and the crosslinking degree is easy to control.

The invention discloses a preparation method and a product of a hydrogel plaster for cold compress. The method comprises the following steps: (1) performing an esterifying reaction on polyethylene glycol, polyvinyl alcohol and acrylic acid in the presence of an esterification catalyst to obtain polyethylene glycol and polyvinyl alcohol mixed acrylate; (2) mixing the polyethylene glycol and polyvinyl alcohol mixed acrylate with water-based tackifying resin, a crosslinking agent, a photoinitiator, a humectant, a mildew inhibitor, a cooling agent and water to obtain a hydrogel plaster stock solution for cold compress; and (3) continuously coating a substrate with the hydrogel plaster stock solution for cold compress through a coater, performing ultraviolet illumination to cure the gel, and cutting and packaging the cured gel to obtain the hydrogel plaster product. The preparation method of the hydrogel plaster has the advantages of convenient sources of raw materials, simple production process, rapidness and completeness in gel curing, and suitableness for mass production, and the obtained product has the advantages of stability in storage, no bubbles, high transparency, obvious cooling effect, good applicability and good moisture retention property.

The invention discloses an impact modifier having a core-shell structure, wherein, the core of the impact modifier contains organo-silioxane crosslinked (methyl) acrylate elastic polymer which includes branching (methyl) acrylic acid C2-C14 alkyl ester elastomer monomer units and silioxane monomer units containing olefinic bonds. The invention also discloses a preparation method for the impact modifier and a molded composition containing the impact modifier. The impact modifier has excellent thermal aging resistance and impact resistance.

The embodiment of the invention discloses a cross-linked polymer space network structure simulation generation method and system, and the method comprises the steps: obtaining a plurality of monomer molecules, and mixing a target number of monomer molecules to obtain a mixed system with a plurality of initial structures; wherein the initial structures are provided with the monomer molecules of the same type and number, and the positions of the monomer molecules in the initial structures are different; sequentially carrying out force field distribution and molecular dynamics relaxation on the mixed system; and on the basis of preset crosslinking parameters, crosslinking all the initial structures in the mixed system by using a preset strategy until the crosslinking conversion rate reaches a target crosslinking conversion rate, ending crosslinking, and obtaining the crosslinked polymer spatial network structure. According to the method and the system, the problem of relatively low time efficiency of crosslinking in the prior art is solved.

The present invention provides a closed-cell foamed rubber sheet whose sealability is less likely to decrease even after long-time use and which has excellent water resistance. The closed-cell foamed rubber sheet of the present invention comprises a rubber-based resin, and is provided by the steps of: providing a foamable resin composition containing the rubber-based resin and a foaming agent; irradiating the foamable resin composition with ionizing radiation to cross-link the foamable resin composition; and foaming the cross-linked foamable resin composition. In the case where the foamable resin composition further contains 0.5 parts by weight or more of a powdery additive other than the foaming agent per 100 parts by weight of the rubber-based resin, the rubber-based resin preferably contains a rubber-based resin ingredient which is in a liquid state at normal temperature.

Disclosed are melt-spun fibers comprising thermoplastic aliphatic polyketone as a first polymer and a selected polymeric component as a second polymer.

These fibers are distinguished by excellent mechanical properties, such as good bending recovery, by very good sliding properties, by high hydrolysis resistance and by high abrasion resistance.

The invention relates to an irradiation crosslinked LSOH (low smoke halogen-free) flame-retardant ethylene propylene rubber elastomer material and a preparation method thereof. The preparation method is characterized in that the irradiation crosslinked LSOH flame-retardant ethylene propylene rubber elastomer material is prepared from a basic rubber A, a basic rubber B, aluminum hydroxide, magnesium hydroxide, 3.5 hydrated zinc borate, talcum powder, zinc stearate, an antioxidant, a crosslinking agent and the like through the steps of mixing the raw materials by using an open mixing machine and then carrying out extrusion by using a five-temperature-period single-screw extruder. When the irradiation crosslinked LSOH flame-retardant ethylene propylene rubber elastomer material burns in a fire, a lot of smoke and gases such as poisonous and corrosive halogen hydride cannot be produced, which is beneficial to the escape of people the personnel escape and avoids secondary hazards of a fire disaster. The material also has the characteristics of good flexibility, good fluidity in the process of extruding, good electrical, mechanical and physical properties, high temperature resistance level (can be used for a long time in a 125 DEG C environment), and the like. The irradiation crosslinked LSOH flame-retardant ethylene propylene rubber elastomer material can be used as a raw material of an insulating layer of an electric wire with soft and movable properties.

The invention belongs to the technical field of high polymer materials, and particularly discloses waterborne polyurethane modified epoxy resin as well as a preparation method and application thereof. The waterborne polyurethane modified epoxy resin is prepared from the following raw materials: an isocyanate monomer, polyol, a hydrophilic modifier and glycidol. An epoxy group is introduced through glycidyl, the glycidyl is adopted as a monomer to synthesize the polyurethane modified epoxy resin, and during preparation, an isocyanate monomer is firstly adopted and reacts with polyhydric alcohol to prepare an-NCO-containing isocyanate prepolymer; compared with a traditional preparation method, the preparation method has the advantages that the epoxy equivalent of epoxy resin is high, a paint film is endowed with excellent flexibility, elongation at break and impact resistance after curing, the corrosion resistance is equivalent to that of epoxy resin, the flexibility is as low as 1mm, and the adhesive force level is level 1; the elongation at break reaches 88-125%, and the impact resistance is gt; the thickness is 50cm.

The invention discloses a reversible crosslinked polycaprolactone/polyethylene glycol with a shape memory function, and a preparation method thereof. The reversible crosslinked polycaprolactone/polyethylene glycol with the shape memory function is prepared from coumarin-terminated polycaprolactone and coumarin-terminated polyethylene glycol by a photocrosslinking process. The shape fixation rate Rf1 is 84.3-100%, the shape fixation rate Rf2 is 86.7-100%, the shape recovery ratio Rr1 is 87.2-100%, and the shape recovery ratio Rr2 is 86.2-100%; and the shape fixation rate R'f1 after reversible crosslinking is 81.7-98.9%, the shape fixation rate R'f2 after reversible crosslinking is 83.0-98.9%, the shape recovery ratio R'r1 after reversible crosslinking is 82.1-99.0%, and the shape recovery ratio R'r2 after reversible crosslinking is 80.2-98.7%. The invention also discloses the preparation method of the reversible crosslinked polycaprolactone/polyethylene glycol with the shape memory function. The reversible crosslinked polycaprolactone/polyethylene glycol with the shape memory function, prepared by the photocrosslinking process, has the advantages of excellent triple shape memory property, reversible crosslinking property, controllable crosslinking degree and biodegradability; and the preparation method adopting lights as a radiation source in a reaction has the advantages of mild reaction conditions, no need to add an initiator, few byproducts, easily available devices, simplicity in operation, and wide application prospects.