Sulfur-free and low ash expandable graphite was prepared by a chemical method using non-high purity mixture mesh natural flake graphite, concentrated nitric acid, potassium permanganate and hydrogen peroxide as mw materials. When expandable graphite was second intercalated by antioxidant, such as saturated potassium dihydrogen phosphate, saturated boric acid, phosphoric acid and the mixture of the three solutions, sulfurfree and high inoxidizability expandable graphite of 280mL/g could be produced. Relationship between inoxidizability and oxidation time, oxidation temperature, expansion volume change of expandable graphite after added antioxidants were researched. Results showed that expandable graphite had a higher antioxidant activity and expansion ratio after added mixture solution of phosphoric acid and potassium dihydrogen phosphate, phosphoric acid and boric acid mixture, phosphoric acid as an antioxidant.%以非高纯混合目天然鳞片石墨、硝酸、高锰酸钾、双氧水为原料,采用化学法经氧化酸化插层、水洗、干燥过程,制备无硫低灰分可膨胀石墨.用磷酸二氮钾饱和溶液、硼酸饱和溶液、磷酸及这3种溶液的混合液作为抗氧化剂进行二次浸渍插层,可制备得到最大膨胀体积为280mL/g的无硫高抗氧化性可膨胀石墨.研究了加入杭氧化剂后膨胀体积变化情况及氧化温度、氧化时间与抗氧化性的关系.结果表明,加入抗氧化剂后的可膨胀石墨具有更高的抗氧化性和膨胀倍数,其中磷酸与磷酸二氢钾混合溶液、磷酸与硼酸混合溶液、磷酸作为抗氧化剂时,膨胀石墨的抗氧化能力较强.
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