31results about How to "Raise the initial decomposition temperature" patented technology

This invention relates to a method for preparing and modifying Al (OH) 3 flame retardant. The method adopts rare earth coupler as the modifier, or rare earth coupler and phosphate compounds as the composite modifier, and utilizes wet or dry technique to prepare and modify Al (OH) 3 flame retardant. The method can largely improve heat resistance of Al (OH) 3 as well as raise its initial decomposing temperature, and the obtained Al (OH) 3 flame retardant can be widely used in rubber and plastic industiries. The method utilizes one-time surface modification instead of multi-step organic / inorganic modification, thus simplifying the modification process. Besides, the method also raises the activity index of the obtained Al (OH) 3 flame retardant, and reduces its oil-aborbency.

The invention discloses a fully deuterated ammonium dinitramide and a preparation method thereof, belonging to the technical field of synthesis of deuterated energetic materials. The invention is simple in purification, and high-purity products can be obtained without adsorption and solvent elution; the product does not contain metal ions such as potassium ions, does not cause catalyst poisoning during use, and can increase the application range of the product. The invention judges the progress of the reaction by measuring the pH of the solution, and the judgment method of the reaction end point is simple; the deuterated ammonia gas can be recycled after being collected, the waste of deuterated raw materials is reduced, and the production cost is reduced. Compared with ordinary ammonium dinitramide, the initial decomposition temperature of perdeuterated ammonium dinitramide is increased to about 150°C, and the thermal stability is significantly increased; the crystal density is increased, and the energy characteristics are also significantly improved. The invention can realize the preparation of perdeuterated ammonium dinitramide, and provides a reference for the industrial production of perdeuterated ammonium dinitramide.

The invention discloses high-efficiency flame-retardant modified melamino-formaldehyde foams. The high-efficiency flame-retardant modified melamino-formaldehyde foams are obtained by performing layer-by-layer self assembling through an alternating reaction formed by soaking or spraying of a positive electrolyte aqueous solution and a negative electrolyte aqueous solution based on a layer-by-layer self-assembling technology, and are deposited on the surface of a foam hold skeleton to form multiple layers of stable flame-retardant films, wherein the limit oxygen index is 35.5 to 46.5%; thermogravimetric residual weight at 700 DEG C and under nitrogen atmosphere is 26.7 to 32.8%; under the condition of cone calorimetric test with the power of 50 kW and in the process of from that the foam can be ignited to that the foam cannot be ignited, heat release peak value is 9.8 to 78.8 kW / m<2>; the foam is difficult to shrink at continuous high temperature of 750 DEG C. The flame-retardant films on the obtained melamino-formaldehyde foams have a strong adhesive force, are washable and have high flame-retardant efficiency and excellent flame-retardant performance. The thickness of each of the flame-retardant films is less than 2 microns, so other properties of the foams are not influenced. The high-efficiency flame-retardant modified melamino-formaldehyde foams are simple to prepare, environment-friendly, and easy for industrialized large-scale production.

The invention discloses a strengthening agent for carbon fiber sizing agents and a preparation method of the strengthening agent, belongs to the technical field of composite materials, and solves theproblems of instable component and poor compatibility of a strengthening agent in the prior art. The strengthening agent comprises polyacrylic acid modified nano-lamella boron nitride dispersion liquid, a dispersing agent, silicone oil and higher fatty acid, nano-lamella boron nitride dispersion liquid is modified by polyacrylic acid to form the polyacrylic acid modified nano-lamella boron nitridedispersion liquid, and a modified mode of the polyacrylic acid includes that acrylic acid is polymerized on the surface of effectively peeled nano-lamella boron nitride in situ. The preparation method includes the steps: mixing the polyacrylic acid modified nano-lamella boron nitride dispersion liquid, the dispersing agent, the silicone oil and the higher fatty acid; ultrasonically dispersing mixture to obtain the strengthening agent for the carbon fiber sizing agents. The strengthening agent and the preparation method can be used for strengthening the carbon fiber sizing agents.

The invention relates to the technical field of catalysts, in particular to intramolecular trifunctional Lewis acid-base pair catalysts, preparation methods and applications, ring topology PMMBL polymers, preparation methods and applications. The intramolecular trifunctional Lewis acid-base pair catalyst provided by the present invention has any one or several structures shown in formulas I to III. The catalyst provided by the present invention adopts the chain growth mechanism of "bimolecular synergy". Two Lewis acid sites of B and one Lewis base site of P of the catalyst simultaneously exist in the same molecular structure through covalent bonding and acidic The application of the weaker B-site Lewis acid is favorable for the ω-end of one polymer chain to attack the α-terminus of the other chain, so that the catalyst structure leaves and the two polymer chains connect end-to-end to form a ring to prepare a high initial heat Degradation temperature and narrow thermal degradation temperature window for ring topology PMMBL polymers.

The invention discloses a preparation method of a highly-ortho boron-modified thermosetting phenolic-based hollow nano-gradient activated carbon fiber membrane. The preparation method of the highly-ortho boron-modified thermosetting phenolic-based hollow nano-gradient activated carbon fiber membrane comprises performing reversed decompressed dehydration on phenol and aldehyde compounds and boric acid with catalysts to obtain highly-ortho boron-modified phenolic resin; then dissolving the highly-ortho boron-modified phenolic resin into alcohol and aldehyde compounds with catalysts for reactionto obtain highly-ortho boron-modified thermosetting phenolic resin; taking the highly-ortho boron-modified thermosetting phenolic resin as a carbon precursor solution for coaxial electrostatic spinning, and then performing heating curing to obtain a highly-ortho boron-modified highly-ortho thermosetting phenolic fiber membrane with the skin-core structure partly inter-soluble; under protection ofN2, performing carbonization and activation to obtain the highly-ortho boron-modified thermosetting phenolic-based hollow nano-gradient activated carbon fiber membrane. Compared with the prior art, the preparation method of the highly-ortho boron-modified thermosetting phenolic-based hollow nano-gradient activated carbon fiber membrane is simple and easy to implement, environmentally friendly, controllable in hollowness and high in yield of carbon fiber as well as mechanical performance.

The invention belongs to the technical field of pyrolysis instruments, in particular to a low-pressure flash pyrolysis flow tube reaction device based on a continuous molecular beam source. It includes a test bench, an installation mechanism, a flash pyrolysis mechanism and a vacuum box; the flash pyrolysis mechanism includes a cylindrical cavity horizontally arranged in the vacuum box, and a sample injection pipe, a water inlet pipe and a water outlet pipe arranged in the cylindrical cavity, and a water cooling chamber It is slidably arranged in the cavity at the other end of the cylindrical cavity, the other end of the injection tube penetrates the water cooling cavity, and the extension end is connected with a silicon carbide tube, and a pair of graphite electrodes is sleeved on the silicon carbide tube; the extension end of the push rod of the linear introducer A sliding table is arranged in the corresponding cylindrical cavity, the extension end of the push rod is fixedly connected with the sliding block, and the upper end of the sliding block is fixedly connected with the corresponding sampling tube. The silicon carbide tube of the invention is used as a reactor, and the graphite electrode is heated to realize rapid temperature rise and reduce secondary reactions, and can reduce the annihilation of active and important reaction intermediates such as free radicals under low pressure, and can realize continuous sampling and improve the reaction power of pyrolysis samples. study research.

The invention discloses a flame-retardant nanocellulose containing a phosphazene group, a preparation method and a flame-retardant polylactic acid thereof. The phosphazene modifier was chemically grafted on the surface of nanocellulose to obtain a novel flame-retardant nanocellulose containing phosphazene groups. The flame-retardant nanocellulose obtained by the invention has excellent thermal stability and carbon-forming ability. Combining it with a phosphorus-containing flame retardant to compound flame retardant polylactic acid can not only significantly improve the flame retardant properties of the material, but also improve its mechanical properties.