摘要
以煤焦油沥青为原料，在高压反应釜中，选择合适溶剂在超临界流体状态下制备了沥青泡沫，经过氧化、炭化制备成泡沫炭。根据沥青的流变性能和溶解性能选择了甲苯作为溶剂，考察了溶剂比例、发泡温度、压力及压力释放速率对沥青泡沫孔结构的影响。从超临界体系相平衡分析了超临界流体对沥青泡沫形成的作用机理。实验表明，在溶剂比例为10％～50％，初始压力2．5～4．0MPa，发泡温度在290～315℃，保温时间4小时，压力释放速率为0．5～1．0MPa／s的条件下，制备出泡孔结构均匀、孔径分布300～1500μ、开孔率高的沥青泡沫。通过调节不同的溶剂比例、发泡温度和压力、压力释放速率等条件，可以控制沥青泡沫的孔结构。
Pitch was foamed in a high-pressured reaction vessel with supercritical fluid（SCF）. The derived pitch foam was oxidized and carbonized into carbon foam. Toluene was chosen as the SCF based on rheological performance and solvability. The influences of foaming conditions like SCF proportions,temperature, pressure and its releasing speed on the structure of pitch foams were studied,Foaming mechanism was expounded from the view of system＇s phase equilibrium, gas nucleation, and growth. The result shows that different types of pitch foam with pores sized in 300-1 500μm,homogeneously distributed,and highly joined could be gotten,with solvent proportions of 10%-15%,under initial pressures of 2.5-4.0MPa, and heated at 290-315℃ for 4 hours. Thus it could be concluded that SCF is suitable to fabricate carbon foam from pitch with well distributed and highly joined pores. Moreover,the pore size,structure,and distribution are easily controlled by this way.
出处
《炭素》
2008年第2期3-10,共8页
Carbon
基金
国家自然科学基金(No.50572015)资助项目
关键词
沥青
泡沫炭
超临界
pitch
carbon foam
supercritical
