微波法制备膨胀石墨及其膨胀特性

以鱼鳞片石墨为原料,浓硫酸作为插层剂,高锰酸钾作为氧化剂,采用化学氧化法制备石墨插层物,再利用微波辐射石墨插层物快速制备膨胀石墨。膨胀后的石墨颗粒呈"蠕虫"状,蓬松粗大。随着鳞片石墨尺寸的减小,膨胀石墨颗粒变得更加纤细,达到最大膨胀体积时高锰酸钾的用量也随之减少。最佳微波时间为30~60 s,此时间段内石墨膨胀完全并且无烧蚀。对于3种不同尺寸的鳞片石墨,颗粒度大于0.42 mm的鳞片石墨在混合质量比m(石墨):m(H2SO4):m(KMn O4)=5:10:4时,达到最大膨胀体积为285 ml·g-1。

Preparation and expanded property of expanded graphite by microwave irradiation

The expanded graphite (EG) could be prepared rapidly by microwave irradiation for graphite intercalation compounds (GIC). GIC was prepared through the chemical intercalation of natural flake graphite and concentrated sulphuric acid, and potassium permanganate was added as oxidizing agent in the progress. GIC samples would show different color and luster with potassium permanganate augmenting. For graphite flakes whose granularity was more than 0.42 mm, the biggest volume expansion was 285 ml·g^-1 when the mass ratio is m(graphite):m(H₂SO₄):m(KMnO₄)=5:10:4. The achieved EG particles were coarse and long. The dosage of potassium permanganate would decrease with graphite flakes size increasing when it reached the biggest volume expansion, the achieved EG particles also would turn more slender. The optimal radiant time was 30-60 s, the achieved EG worm was scorched partly in excess radiant time. In the process of microwave irradiate GIC, 30%-35%(mass) GIC would be lost.