Preparation method of expansible graphite with flame retardant property

Abstract

The invention discloses a preparation method of expansible graphite with a flame retardant property. The preparation method comprises the following steps: dissolving ammonium polyphosphate and potassium dichromate accounting for 20%-50% of the mass of the ammonium polyphosphate in a phosphoric acid having the mass fraction of 75% to form a phosphoric acid solution in which the concentration of the ammonium polyphosphate is 0.02g / ml-2g / ml; taking a mixed solution of sulfuric acid and nitric acid or a concentrated sulfuric acid solution and oxidizing graphite by use of potassium dichromate accounting for 10-20% of the mass of the graphite to obtain a primary expansible graphite; reacting the phosphoric acid solution with the primary expansible graphite at a temperature in the range of 70-80 DEG C, after the reaction is finished, filtering and washing with water until the pH is in the range of 6-7, and drying at 100 DEG C for 6-12 hours to obtain the expansible graphite with the flame retardant property. The preparation method of the expansible graphite with a flame retardant property is characterized in that a phosphorous compound is inserted between the layers of the graphite so that the adhesion of the prepared expansible graphite with the high flame retardant property to each other can be improved so that a better flame retardant effect can be achieved, in addition to a relatively high expansion volume of the expansible graphite.

Description

technical field [0001] The invention belongs to the technical field of preparation of expanded graphite materials, and in particular relates to a preparation method of expandable graphite with flame-retardant properties. Background technique [0002] Due to the interaction between the carbon atomic layer and the intercalation layer atoms, the expandable graphite has a series of new properties, especially when the expandable graphite is subjected to high temperature, it shows a volume expansion of hundreds of times, which makes it suitable for fire. When the flame is suffocated by the instantaneous increase in volume, the purpose of flame retardancy and fire prevention is achieved. Expandable graphite with sulfuric acid as an intercalation agent is a commercial product widely used at present. The flame-retardant polymer material has the advantages of non-toxicity, low smoke, low burning rate, and low heat release rate when burning. The development trend of combustible materi...

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Problems solved by technology

[0004] Chemical oxidation is currently the main method for preparing expandable graphite. Sulfuric acid, nitric acid, phosphoric acid, etc. are mostly used as intercalation agents. In recent years, in order to reduce the sulfur content of expanded graphite, the preparation of low-sulfur or sulfur-free expandable graphite has gained relatively Pay more attention, but there is no report on high flame retardant expandable graphite