辅助插层剂对分步插层法制备膨胀石墨的影响

以硝酸、乙酸为主插层剂,KMnO_4为氧化剂,磷酸、硝酸为辅助插层剂,采用分步插层法制备膨胀石墨。通过单因素变量法,在研究主插层剂最佳插层条件的基础上,考察辅助插层剂(磷酸和硝酸)对制备膨胀石墨的影响。结果表明,在最佳制备条件下,膨胀石墨的膨胀体积约为116 mL/g;当加入辅助插层剂磷酸时,膨胀体积约为180 mL/g;继续加入辅助插层剂硝酸时,膨胀体积最大约为172 mL/g。说明加入辅助插层剂磷酸后石墨的膨胀体积明显增大,加入辅助插层剂硝酸后石墨的膨胀体积略有下降。用SEM进行表征,结果与单因素试验结果一致,说明辅助插层剂磷酸对石墨膨胀体积有明显影响。

Effects of Ancillary Intercalation Agents on Preparation of Expandable Graphite with Two-step Intercalation

The expanded graphite was prepared by two-step intercalation method, nitric acid and acetic acid as the main intercalation agent, KMnO4 as oxidant, phosphoric acid and nitric acid as ancillary intercalation agents. On the basis of studying the optimum condition of the main intercalation agent, the influences of ancillary intercalation agents (phosphoric acid and nitric acid) on preparation of expanded graphite were investigated by single factor method. The results showed that the expansion volume was about 116 mL/g under the optimum preparation conditions, the expansion volume was about 180 mL/g when adding phosphoric acid, and the expansion volume was about 172 mL/g when adding nitric acid. It is showed that the expansion volume of expanded graphite increases obviously after adding phosphoric acid, and decreases slightly after adding nitric acid. The results are in agreement with those provided by SEM and the single factor experiments, the effect of phosphoric acid as ancillary intercalation agent on the expansion volume of expanded graphite was obvious.