89 results about "Oxidized cellulose" patented technology

A device for promoting the clotting of blood in body cavities includes a flexible body portion; an expandable member located on the flexible body portion; and a blood clotting material attached to the expandable member. When used, insertion of at least a portion of the blood clotting material into the body cavity causes at least a portion of the blood clotting material to contact blood emanating from a bleed site. Methods of providing therapies to tube-shaped organs include the steps of providing suitable devices having expansion capabilities, positioning the devices at the appropriate bleed sites, and expanding the devices to cause blood clotting materials to contact the bleed sites. Materials that may be used as the blood clotting material include zeolites, molecular sieve materials, diatomaceous earth, clay, silica-based materials, oxidized cellulose, carboxymethyl cellulose, bioactive glass, biological hemostats, chitosan, and combinations of the foregoing.

A membrane is provided including a coating layer having cellulose nanofibers produced from oxidized cellulose microfibers and an electrospun substrate upon which the coating layer is applied. The nanofibers of the electrospun substrate have a diameter greater than that of the cellulose nanofibers. The membrane also has non-woven support upon which the electrospun substrate is disposed. Microfibers of the non-woven support have a diameter greater than that of the nanofibers of the electrospun substrate. Application of electrospun membrane is in microfiltration area, while the cellulose nanofiber membrane serves in ultra-filtration, nanofiltration, and reverse osmosis after chemical modification.

The present invention relates to the preparation of a series of oxidized cellulose esters suitable for use as a drug carrier in the development of biodegradable controlled and/or sustained release pharmaceutical, agricultural, and veterinary compositions, such as films, compacts, microspheres, and pellets. The esters are prepared by acylation of oxidized cellulose having at least 3% carboxyl groups. The resulting oxidized cellulose esters are soluble in aqueous alkaline solutions, water, and a variety of organic solvents.

A method for forming an embolism within a blood vessel is disclosed. The method includes including: implanting a plurality of oxidized cellulose microspheres into a lumen of a blood vessel to at least partially block the lumen.

[Problem] To provide a composition for film formation comprising cellulose fibers, a layered inorganic compound, and a water-soluble polymer, which are each dispersed on nano level, a method for preparing a cellulose dispersion capable of forming a moisture-resistant film containing cellulose nanofibers, a gas-barrier laminate obtained by use of the dispersion, and a packaging material using the laminate. [Solution] A film-forming composition comprising at least cellulose fibers and a swollen inorganic compound is prepared. The method of preparing a cellulose dispersion comprises the steps of oxidizing cellulose, fibrillating the thus oxidized cellulose to prepare cellulose nanofibers, and adding a water-soluble polymer and inorganic particles to the dispersion containing the cellulose nanofibers.

The invention provides a method for preparing adsorbable oxycellulose through a ramie oxidation degumming process. The method includes the steps that ramie original hemp serves as a raw material, the original hemp is smashed into short fibers through a smashing machine, and the short fibers are added with deionized water and soaked for pretreatment; a degumming solution is prepared from an oxidizing agent, a stabilizing agent, a fiber expanding agent, a penetrating agent, a chelating agent and water, the ramie original hemp and the degumming solution are mixed, gum in the ramie original hemp is fully removed by means of oxidizability of hyperoxide, and cellulose with active hydroxyl groups is oxidized into oxycellulose containing a great number of formyl groups; the oxycellulose is separated from water and dried to obtain the oxycellulose in the powder state. The method is simple in flow path, environmentally friendly, low in requirement for equipment and beneficial for large-scale production and has good economic and social benefits, the total reaction time is shortened, chemicals and cost are saved, efficiency is greatly improved, reaction conditions are moderate, and additional value of the cellulose is substantially increased.

The invention discloses a method for preparing cellulose nanofiber dispersion liquid, which comprises the following steps: dispersing a cellulose raw material in a drainage buffer solution system with a pH value of 4-5, and adding laccase and TEMPO so as to prepare a laccase-TEMPO oxidation system; continuously pumping oxygen into a reaction system so as to carry out oxidation reaction for 24-130 hours; after the reaction is completed, carrying out centrifugal filtration on the obtained object so as to obtain supernatant for repeated use; cleaning an obtained precipitate (i.e. water-insoluble oxidized cellulose) to be neutral by using deionized water; and adding deionized water, stirring the obtained mixture so as to obtain an oxidized cellulose water suspension, carrying out homogenation and ultrasonic treatment, and centrifugalizing the obtained object so as to obtain supernatant, i.e. oxidized cellulose nanofiber dispersion liquid. According to the invention, the oxidation efficiency is guaranteed, and the pollution caused by halogen elements to the environment is avoided; and the reaction system can be repeatedly used, so that the utilization rate of the oxidation system is improved, the oxidation effect is uniform, the yield of cellulose nanofibers is increased, and high-length-to-diameter-ratio nanofibers can be obtained.

The invention discloses a preparation method of corn stalk modified cellulose gel capable of adsorbing heavy metal ions. The preparation method comprises the steps of stripping and shearing air-dried corn stalks to obtain two raw materials including basts and piths, respectively carrying out glacial acetic acid/hydrogen peroxide/cobalt acetate treatment, and then, further reacting after dropwise adding a potassium hydroxide solution to obtain two parts of cellulose; dissolving bastuse by using a low-temperature lithium hydroxide/thiourea method; oxidizing pith cellulose by using a piperidine-N-oxide radical/cooxidation system method to obtain a product, carrying out solid-liquid separation on the product, carrying out alcohol precipitation and freeze drying on filtrate to obtain pith oxidized cellulose, dispersing the product into a chitosan/acetic acid solution, and heating to obtain an oxidized cellulose/chitosan cross-linked product; and mixing the cross-linked product and a bastuse solution, molding by using a mold, carrying out alcohol bath dehydration, washing and drying to obtain the corn stalk modified cellulose gel. The gel prepared by using the method is microporous and flaky and has relatively high adsorption capacity for heavy metal ions such as Zn<2+>, Fe<3+>, Cd<3+> and Cu<2+>.

The invention provides a method for preparing bleeding stopping oxidized celluloses in ramie oxidation degumming procedures. The method includes smashing raw ramie to obtain short fibers and soaking the short fibers to sufficiently moisten the short fibers and allow the short fibers to sufficiently swell; mixing the pretreated raw ramie short fibers and degumming solution with one another to obtain mixtures, heating the mixtures, then preserving heat, sufficiently removing colloid in the raw ramie by the aid of oxidability of specific oxidizing agents and simultaneously oxidizing celluloses with active hydroxyl to obtain oxidized celluloses with a large quantity of carboxyl; soaking oxidized and treated fibers by the aid of organic solvent aqueous solution and removing the unreacted oxidizing agents; separating the oxidized celluloses from water and carrying out drying treatment on the oxidized celluloses to ultimately obtain the powdery bleeding stopping oxidized celluloses. The method has the advantages that processes are simple, the original two working procedures are combined into a single working procedure, accordingly, the total reaction time can be shortened, medicines and the cost can be saved, and the efficiency can be greatly improved; the bleeding stopping oxidized celluloses which are products prepared by the aid of the method are high in bleeding stopping speed and bleeding stopping efficiency and can be widely applied to quickly stopping bleeding under conditions of war wound, trauma and the like, and stable effects can be realized.

The invention provides a method for preparing heavy metal ion adsorbents in ramie oxidization degumming procedures. The method includes smashing raw ramie to obtain short fibers, adding the short fibers into deionized water and soaking the short fibers; mixing the raw ramie and degumming solution with each other to obtain mixtures, heating the mixtures, sufficiently removing colloid in the raw ramie by the aid of oxidizing agents, and simultaneously oxidizing celluloses with active hydroxyl into oxidized celluloses with aldehyde; soaking reacted fibers in organic solvent aqueous solution and removing the unreacted oxidizing agents; separating the oxidized celluloses from water and drying the oxidized celluloses to obtain powdery oxidized cellulose adsorbents; preparing heavy metal solution, adding the oxidized cellulose absorbents into the heavy metal solution, carrying out vibration adsorption at the room temperature and measuring heavy metal ion absorption capacity numerical values. The method has the advantages that the adsorbents prepared by the aid of the method are low in residual gum content, moderate in crystallinity degree and polymerization degree and high in aldehyde content, and excellent heavy metal ion adsorption effects can be realized; working procedures are simplified, the total reaction time can be shortened, medicines and the cost can be saved, and the efficiency can be greatly improved.

The invention relates to functional nano-crystalline cellulose hydrogel and a preparation method thereof. The interior of the hydrogel is of a uniform porous mesh structure, and the pore size of the hydrogel is 30-100 microns. The hydrogel is prepared by the following steps: dispersing TEMPO oxidized cellulose in water to prepare nano-cellulose dispersion, mixing with cells to prepare bio-ink, andprinting into an ionic crosslinking agent by utilizing a 3D bio-printing technology, thereby obtaining the product. The shape of the product can be designed according to needs. The renewable resourcecellulose serves as a raw material, and the functional nano-crystalline cellulose hydrogel with advantages of being excellent in mechanical property, excellent in biocompatibility and applicable to bio-printing is prepared. The prepared hydrogel serves as a nano-cellulose based tissue engineering material, is particularly one of tissues such as bones, cartilage, skin, blood vessels, liver, heartand the like, the application range of the cellulose is widened, and a novel pathway is provided for application research of the cellulose in the biomedical field.

A process for forming microspheres is disclosed. The process includes: forming a first plurality microspheres comprising at least one bioactive agent and modified cellulose; contacting the first plurality of microspheres with a solution of a biodegradable polymer to form a discontinuous phase liquid; contacting the discontinuous phase liquid with a continuous phase liquid to form an emulsion; and extracting a second plurality of microspheres from the emulsion, the second plurality of microspheres comprising the first plurality of microspheres.

The invention discloses a preparation method of cellulose-based nitrogen-doped fluorescent carbon quantum dots, and belongs to the field of fluorescent nano material science. The method comprises thefollowing steps of: (1) placing cellulose in a HNO3/H3PO4/NaNO2 oxidation system, performing selective oxidation on C-6 hydroxyl groups, adding ultrapure water, performing static settlement, performing centrifugation, washing, drying and ultrasonic treatment to obtain an aqueous solution of oxidized cellulose nanoparticles; and (2) mixing the aqueous solution of the oxidized cellulose nanoparticles with ammonia water, pouring the mixture into a reaction kettle, performing a hydrothermal reaction, cooling to room temperature, performing ultrasonication and centrifugation so as to remove insoluble precipitate thoroughly and obtain supernatant, and finally conducting rotary evaporation on the supernatant to obtain the cellulose-based nitrogen-doped carbon quantum dots. The raw materials haverich sources and low price, and the preparation process is green and simple, and needs no expensive equipment; the prepared cellulose-based nitrogen-doped carbon quantum dots have high fluorescence intensity, low toxicity and good water solubility, and can be applied to detection of Fe<3+>.

The invention discloses a method for preparing oxidized cellulose. The preparation method comprises the following steps: a, putting an oxidized cellulose material into inert solution; b, adding an oxidant into the inert solution, sealing the solution, stirring the solution for 10 to 12 hours by using a magnetic stirrer at the temperature of between 20 and 60 DEG C; c, taking the oxidized cellulose material out, and washing the oxidized cellulose material with purified water; d, drying the oxidized cellulose material by using a centrifugal machine, and then washing the oxidized cellulose material by cleaning solution; and e, drying the oxidized cellulose material to obtain a finished product. Because the inert solution is used as a reaction solvent, the oxidization reaction can be performed under the controllable conditions, the reaction is even, and the manufactured oxidized cellulose and oxidized regenerated cellulose products are stable and easy to store; and the reaction solvent and the oxidant can be reclaimed for recycle, so the method is economic and environment-friendly, and the production cost is greatly reduced.

The invention discloses a synthesis method of high-carboxylation-degree oxidized cellulose, comprising the steps of combining pre-treatment and multistep oxidization to fully oxidize a cellulosic material, namely, first sealing, mixing and ball-milling the cellulosic material and dry ice and exposing a sample to air to realize the pre-treatment process after finishing ball-milling, then adopting NaNO3 and H2SO4 for carrying out primary oxidization on the material, and carrying out secondary oxidization by adopting KCLO4 as an oxidizing agent, wherein a reaction is performed at the temperature of 30 to 40 DEG C and the reaction time is 30 to 60 min; finally, further oxidizing the material subjected to the secondary oxidization by adopting KCLO, wherein the oxidization temperature is 50 to 60 DEG C and the time is 50 to 65 min. An oxidized cellulose product obtained through the synthesis method is relatively high in content of carboxyl, the content of the carboxyl can reach up to 35.6 percent to 48.7 percent, and the product has good application prospect in the technical field of biological medicine materials.

A method for producing a modified sawdust sorbent. The method involves sulfonating sawdust with sulfuric acid and oxidizing the sulfonated sawdust with hydrogen peroxide. The method yields a modified sawdust sorbent containing sulfonated and oxidized cellulose. The modified sawdust sorbent has a higher surface area, higher organic dye adsorption capacity, and more rapid organic dye adsorption rate than unmodified sawdust. Also disclosed is a method of using the modified sawdust sorbent for organic dye removal from water.

The present invention relates to a method of obtaining a solid material based on a polymer having its cellobiose units exhibiting the following characteristics:

• • at least some of the cellobiose units have at least one carboxylic acid function attached to the C₆ carbon, the other C₆ carbons having a primary alcohol function attached thereto; and
  • at least some of the cellobiose units have at least one of the two rings open between the C₂ and C₃ carbons, the other C₂ and C₃ carbons forming a ring and having an alcohol function attached thereto.

Such a material, advantageously a textile, may be used as a compress.

Cellulose nanofibers are produced by means of a method comprising a step (A) of oxidizing a cellulosic starting material in the presence of an N-oxyl compound and a step (B) of forming the oxidized cellulosic starting material into nanofibers by defibrating the oxidized cellulosic starting material, and a step (C) of performing at least one selected from the following steps: a step (C-1) of treating the cellulosic starting material in water having a hydroxide ion concentration of 0.75 to 3.75 mol/L prior to performing the step (A); and a step (C-2) of subjecting the oxidized cellulosic starting material obtained from the step (A) to hydrolysis in an alkaline solution having a pH between 8 and 14 after performing the step (A) and prior to performing the step (B).

The invention discloses cellulose nanoparticles and a preparation method thereof. Dialdehyde cellulose is generated by utilizing sodium periodate oxidized cellulose; the dialdehyde cellulose and aminereact to generate Schiff base; then the Schiff base is injected into water to generate the cellulose nanoparticles; the cellulose nanoparticles have good pH (Potential of Hydrogen) responsiveness andwide application.