44results about How to "Overcome the problem of easy reunion" patented technology

The invention discloses a macroscopic preparation method of a cellulose nanocrystal (CNC), which is green and environment-friendly. Firstly, cellulose is crushed and then is pretreated; afterwards, an oxometallate solution and an organic acid are added, the oxydrolysis is carried out, and the CNC with a carboxyl group on a surface is obtained after centrifugal dialysis treatment. The yield of the preparation method can exceed 70 percent; the length of the made CNC can be adjusted in the range of 195nm to 260nm; the content of the carboxyl group on the surface can reach 50mmol/g; compared with a CNC made by a sulfuric-acid acid hydrolysis method, the CNC made by the macroscopic preparation method provided by the invention is increased by 50 to 100 DEG C in heat resistance; used oxometallate and organic acid are both green reagents and are further a few in use levels; problems that the preparation cost of the CNC is high and further the environmental pollution is easily caused, and the like, at present are solved.

The invention relates to a preparation method of a composite material containing lactobionic acid-modified graphene oxide, and the method is as follows: chemically bonding graphene oxide (GO) and PEI (polyethyleneimine) in dimethyl sulfoxide by the effect of activator EDC (1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide), dialyzing, and freeze-drying for synthesis of GO-PEI; dissolving the LA in a phosphate buffer solution, adding EDC and NHS (N-Hydroxysuccinimide) for activation, adding NH2-mPEG-COOH, reacting for 12-24h at room temperature, dialyzing, and freeze-drying to obtain PEG-LA; dissolving the GO-PEI in water, adding a FITC (fluorescein isothiocyanate) solution; adding the EDC and the NHS into the PEG-LA for activation, adding the GO-PEI solution for reaction to obtain GO-PEI-FI-PEG-LA, adding triethylamine for mixing, adding acetic anhydride, reacting at room temperature, dialyzing, and freeze-drying to obtain the graphene oxide composite material. The preparation process of the preparation method is simple, the experimental conditions are normal temperature and pressure, and the preparation method is easy to operate.

The invention discloses a small-particle-size metal phosphide nanoparticle/reduced graphene composite material and a preparation method thereof. The preparation method comprises the following steps: 1) preparing silica-coated metal oxide composite particles; 2) loading the composite particles onto graphene oxide to obtain a graphene oxide-based compound; 3) removing silica of the composite particles in the graphene oxide-based compound; and 4) carrying out phosphating treatment so as to obtain the small-particle-size metal phosphide nanoparticle/reduced graphene composite material. Metal phosphide in the composite material of the invention has a small particle size, in a range of 3 nm to 5 nm; and the phosphide nanoparticles are highly dispersed in reduced graphene, which is favorable forincreasing the exposure degree of active sites. The preparation method is simple in process, low in cost, and favorable for large-scale production.

A three-layer vesicular polyaniline/graphene composite material and a preparing method thereof are disclosed. The composite material is prepared by firstly preparing layer-number-adjustable SiO2, preparing a layer-number-adjustable SiO2/polyaniline composite material by adopting the layer-number-adjustable SiO2 as a hard template and adopting aniline as a raw material through an in-situ polymerization process, etching SiO2 to obtain three-layer vesicular polyaniline, preparing a three-layer vesicular polyaniline/graphene oxide composite material through a graphene oxide self-assembling process, and preparing the three-layer vesicular polyaniline/graphene composite material through a high-temperature hydrothermal reduction process. The vesicular polyaniline/graphene composite material having same layer numbers can be obtained by regulating the layer-number-adjustable SiO2. No oxidant or reductant is needed. The method is green. During preparation of the three-layer vesicular polyaniline/graphene composite material, the method is simple, safe in process, low in energy consumption and high in operability.

The invention discloses a graphene-polypyrrole-gold nanoparticle composite material which is characterized in that a method combining in-situ chemical polymerization with electrostatic adsorption is adopted to load gold nanoparticles onto a graphene-polypyrrole composite material. The preparation method comprises the following steps: 1) configuration of a solution; 2) preparation of a polypyrrole-graphene nano-composite material by a mixed reaction of the solution; 3) preparation of a gold nanoparticle solution; 4) adsorption of the gold nanoparticles. The invention further discloses the application of the graphene-polypyrrole-gold nanoparticle composite material, and the composite material is applied to the modification of electrodes of an impedance type escherichia coli biosensor, wherea linear range of detection of the escherichia coli is 1*102-1*107 CFU/mL, and the minimum detection limit is 100 CFU/mL. The impedance type escherichia coli biosensor prepared by the invention has the advantages of simple operation, low cost, convenient use, high selectivity and the like, and thus has great potential application values in the fields of food safety, clinical analysis and the like.

The invention discloses a preparation method of silicon-coated nano magnetic spheres. Magnetic spheres adsorbing silicon spheres are obtained through preparing a silicon sphere solution containing silicon dioxide nanoparticles, preparing the magnetic spheres and stirring and mixing the silicon sphere solution and the magnetic spheres; the magnetic spheres adsorbing the silicon spheres are transferred into an alcohol-water system and the silicon spheres form silicon layers on the surfaces of the magnetic spheres by using a TEOS sol-gel method; and the product silicon-coated nano magnetic spheres are obtained through washing after magnetic separation. The preparation method of the silicon-coated nano magnetic spheres is simple, safe, low in raw material cost and suitable for industrial large-scale production; the prepared nano magnetic spheres are good in dispersity and high in magnetic responsiveness; and the monodisperse silicon-coated nano magnetic spheres have a wide application prospect in the fields of bioseparation, environment, catalysis, solid-phase extraction and the like.

The invention discloses a foamed nickel/MXene-Co3O4 composite electrode and a preparation method thereof. The preparation method comprises the following steps of: (1) pretreatment of foamed nickel, namely, taking the foamed nickel, carrying out ultrasonic cleaning with sulfuric acid, ethanol and deionized water in sequence, and performing drying at a constant temperature; and (2) preparation of a composite electrode, namely, mixing MXene and Co3O4 to prepare mixed powder, coating the surface of the foamed nickel with the mixed powder, and performing vacuum plasma sintering to prepare the composite electrode. The foam material composite electrode is prepared through the foamed nickel, the MXene and the Co3O4, the MXene-Co3O4 mixed powder is stably combined through the foamed nickel under the high-temperature and high-pressure effects of a vacuum plasma sintering furnace, use of an adhesive is avoided, the preparation cost is reduced, and the preparation time is only 40-60 min; the organ-shaped structure of MXene can effectively accommodate and disperse a catalyst, the problem that the catalyst is easy to agglomerate is overcome, the activity and stability of the catalyst are improved, and the prepared electrode is large in specific surface area, and good in conductivity, and an electrode material with excellent performance can be formed.

The invention provides a method for obtaining a nano Cu-Sn-graphite composite coating and a Cu-Sn-graphite electroplating solution. The method comprises the following steps: adding a nano graphite sol prepared by an electrolytic process into a Cu-Sn plating solution to prepare a Cu-Sn-graphite electroplating solution, putting a metal component into the Cu-Sn-graphite electroplating solution, and carrying out electroplating under the following conditions to obtain the composite coating containing copper, tin, graphite and copper-tin crystallized product: the temperature is 35-45 DEG C, the stirring speed is 100-200 r/min, the pH value is 9-10, the current form is pulse current, the current density is 2-4 A/dm<2>, the duty ratio is 30-80%, and the frequency is 50-5000Hz. The method can perform plating on a complex curved surface, has the advantages of no pollution of the plating solution and the like, and can easily implement large-scale production. The coating obtained by the method has the advantages of excellent wearability, low friction factor, favorable corrosion resistance, favorable compactness, uniform and controllable thickness, no pinhole steam drum and the like.

The invention discloses a cadmium oxide nanometer gas-sensitive element with a secondary pore structure. The cadmium oxide nanometer gas sensitive element is synthesized through the following steps: with ethylene glycol monomethyl ether as a solvent, preparing a mixed solution of 0.1 M of zinc acetate and 0.2 M of ethanolamine, soaking a glass slide into the mixed solution, and carrying out annealing treatment; preparing a mixed solution of 0.025 M of zinc nitrate and 0.025 M of hexamethylene tetramine, soaking the above-mentioned glass slide into the mixed solution, and carrying out heat-preserving so as to obtain a nanorod array of zinc oxide, wherein the nanorod array is used as a seed layer for growing cadmium oxide; placing cadmium sulfide (CdS) powder into an evacuated tubular furnace, placing an above-mentioned zinc oxide-grown substrate at a position 30 cm below the cadmium sulfide (CdS) powder, then introducing nitrogen and air, carrying out heating to 650 DEG C so as to obtain a nanosheet array of cadmium (Cd), and carrying out heat-preserving at 360 to 440 DEG C for 30 min so as to obtain a nanometer structure of cadmium oxide; and cutting the glass slide into a rectangular shape with a size of 0.5 cm * 1.0 cm, and carrying out coating with electrodes so as to prepare the gas-sensitive element. The gas-sensitive element provided by the invention has the following advantages: at a temperature of 215 DEG C, sensitivity to diethyl ether with a concentration 100 ppm is 138%, and response time and recovery time are 15 seconds and 27 seconds, respectively; meanwhile, the synthetic process is simple, safe and controllable, has low cost and is applicable to large-scale production.

The invention discloses a nanometer onion carbon enhanced titanium-based composite material and a preparation method thereof. The composite material is mainly prepared from nanometer onion carbon andbase body titanium, wherein the nanometer onion carbon is used as an enhancing phase and is uniformly distributed in the metal titanium base body to achieve a diffusion enhancing effect. The inventionalso discloses a preparation method of the nanometer onion carbon enhanced titanium-based composite material. By aiming at the defects in the prior art, nanometer diamond is used as raw materials tosynthesize the nanometer onion carbon; the nanometer onion carbon is added into the titanium base body to realize the uniform distribution; sintering shaping is performed to obtain the compact titanium-based composite material. The distribution of the nanometer onion carbon in the titanium-based composite material prepared by the method is uniform; the impurity content is low; the complete form can be maintained in the base body, so that the composite material has excellent comprehensive mechanical property.

The invention provides high-dispersity indium oxide and a preparation method thereof. The preparation method comprises the following steps: a) taking metal indium as an anode, an inert electrode as a cathode and an ammonium nitrate aqueous solution as an electrolyte, and obtaining indium hydroxide slurry through an electrolytic method; b) adding an indium nitrate solution into the indium hydroxide slurry obtained in the step a) to enable the mass ratio of the added indium ions to indium hydroxide to be 0.01%-1%, adjusting the pH value to be 4-8, then carrying out hydrothermal reaction, and washing and drying a product to obtain indium hydroxide powder with high crystallinity and high dispersity; and c) calcining the high-crystallinity and high-dispersity indium hydroxide powder obtained in the step b) to obtain the high-dispersity indium oxide. According to the preparation method, indium hydroxide and indium oxide which are uniform in size distribution, high in dispersity and complete in crystal structure are successfully prepared in an electrolytic hydrothermal method combined mode, and the problem that indium oxide prepared from fine indium hydroxide powder synthesized through a common electrolytic method is prone to agglomeration in the calcining process is solved.

The invention discloses a preparation method of a graphene oxide coated ceramic particle corrosion-resistant gradient coating. The preparation method comprises the following steps: preparing graphene oxide coated Cr3C2 ceramic particles, carrying out dispersion reaction on the graphene oxide coated Cr3C2 ceramic particles and metal oxide powder to generate a hybrid reactant, finally mixing the hybrid reactant with ceramic aggregate and an adhesive, and curing and sintering to prepare the corrosion-resistant ceramic coating. The core-shell structure of the ceramic particles and the graphene oxide is favorable for improving the bonding strength of the graphene oxide and a ceramic matrix, avoiding gaps on an interface, improving the compactness of the coating, reducing the generation of cracks of the coating and improving the high-temperature corrosion resistance of the coating; and meanwhile, the core-shell structure is beneficial to improving the oxidation resistance of the coating and prolonging the service life of the coating.

The invention discloses a method for modifying cellulose nanocrystals by using a photoresponsive fluorine-containing amphiphilic block copolymer. The method is specifically implemented according to the following steps: step 1, preparing a hydrophilic acrylate polymer; 2, preparing a hydrophilic acrylate copolymer containing an epoxy group; step 3, preparing a fluorine-containing amphiphilic blockcopolymer; step 4, preparing the pure photoresponsive fluorine-containing amphiphilic block copolymer; and step 5, preparing the photoresponsive fluorine-containing amphiphilic block copolymer modified cellulose nanocrystals. According to the invention, the problems of strong hydrophilicity and easy agglomeration of cellulose nanocrystals are overcome, and the material is endowed with the characteristic of photoresponse.