一种用于制备介孔碳的碳质原料的碳化行为

Analysis of Pyrolytic Process of a Phenolic Resin Used to Fabricate Mesoporous Carbon Monoliths

采用SEM、XRD及TG等手段分析了一种用于制备介孔碳单体的酚醛树脂的碳化行为,着重考察了碳化产物的晶体结构随碳化温度的变化情况。结果表明,酚醛树脂碳化是一个有机向无机转变且结构不断石墨化的过程。500～800℃是酚醛树脂向玻璃碳转变的过渡阶段。800℃以后,随温度升高,玻璃碳中具有石墨结构的微晶堆积块不断长大及有序化,从而促使玻璃碳的石墨化程度加强,其结果体现在玻璃碳中的孔隙减少以及体积收缩。但是,即使在1200℃下酚醛树脂仍然未被完全石墨化。

The pyrolytic process of a phenolic resin（PF）,which is used as precursor to fabricate mesoporous carbon monoliths,is investigated by SEM,XRD and TG. The results show that PF is initially formed from glassy carbon at 800℃. Then,with increasing pyrolytic temperature, the crystalline stacks with graphite structure in the glassy carbon are growing-up and ordering, which induce graphitization of the glassy carbon. As a result, the number of the pores in glassy carbon deceases, the volume of glassy carbon contracts and the bulk density increases. However, the PF is not completely graphitized even if the pyrolytic temperature reaches 1200℃. Moreover, there are three temperature ranges,in which the maximum of weight-loss velocity occurs,during pyrolysis of PF. Thus, it is indispensable to establish reasonable heating program for these temperature ranges in order to avoiding the crack of the carbonized products.