低温可膨胀石墨的制备及插层过程特性

doi:10.16085/j.issn.1000-6613.2017-0147

摘要/Abstract

摘要： 可膨胀石墨作为一种新型功能性碳素材料应用广泛，尤其在防火阻燃材料中备受关注，但由于膨化温度过高而在实际生产中受到限制。现以50目天然鳞片石墨为原料，以KMnO₄/HClO₄/NH₄NO₃作为氧化插层体系，探索低温高倍率可膨胀石墨的制备工艺，采用XRD、FTIR和SEM对鳞片石墨、可膨胀石墨及膨胀石墨的结构、形貌和官能团进行了表征和分析。获得插层最佳反应条件为石墨∶KMnO₄∶HClO₄∶NH₄NO₃（质量比）=1∶0.45∶8∶0.12，连续搅拌15min，搅拌速度200r/min，起始膨胀温度为150℃，400℃下膨胀容积为430mL/g。分析表明：经插层后石墨层边缘和层间接枝了插层剂的含氧基团，导致晶体结构完整性下降，层间距增大，层内结构未发生变化。经膨胀后，低温气化的酸根离子呈气体逸出，撑开石墨片层形成丰富的孔隙结构。

关键词: 可膨胀石墨, 低温, 低温可膨胀石墨, 氧化插层, 膨胀容积, 制备表征

Abstract: Expandable graphite is widely applied as a new functional carbon material,especially in the fields of flame resistance and fireproofing. However,its application is limited because of the high expansion temperature. The preparation of low temperature graphite by chemical oxidation is discussed,which was prepared by 50 mesh natural graphite and KMnO₄/HClO₄/NH₄NO₃ mixed compounds used as chemical intercalant and oxidizer,respectively. In addition,the structure,morphology and functional groups of the products in different stages are characterized by XRD,FTIR and SEM. The results show that the best proportion is 1∶0.45∶8∶0.12 for flake graphite: KMnO₄: HClO₄: NH₄NO₃(mass ratio),and the reaction time is 15min with stirring speed of 200r/min. The initial expansion temperature is 150℃ and expansion volume can reach 430mL/g at 400℃. The analysis shows that crystal structural integrity becomes worse and the interlayer spacing is increased due to oxygen-containing groups grafted onto graphite,whereas the layer structure is stable. Acid radical ions escape from the graphite as gas after expansion and flake graphite is changed into graphite sheet with plenty of pores.

Key words: expandable graphite, low temperature, low temperature expandable graphite, oxidization intercalation, expansion volume, preparation characterization

中图分类号:

TD127.11

罗立群, 刘斌, 王召, 魏金明, 安峰文. 低温可膨胀石墨的制备及插层过程特性[J]. 化工进展, 2017, 36(10): 3778-3785.

LUO Liqun, LIU Bin, WANG Zhao, WEI Jinming, AN Fengwen. Preparation of low temperature expandable graphite and the characteristics of intercalation[J]. Chemical Industry and Engineering Progress, 2017, 36(10): 3778-3785.

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