煤基炭泡沫孔结构调控

以肥煤镜质组富集物为前驱体, 采用高压渗氮法制备煤基炭泡沫, 研究了发泡温度、发泡压力和发泡时间对炭泡沫孔结构的影响。利用SEM观察炭泡沫的孔胞形貌, 同时利用Nano Measurer分析软件统计SEM照片孔胞直径分布和孔喉直径分布以及平均孔径。结果表明: 微孔塑料成核理论可以定性解释炭泡沫的孔结构变化趋势。发泡温度的升高导致成核密度增加, 同时导致气体在胶质体的溶解度降低, 不利于孔胞长大。发泡压力的增大导致炭泡沫的孔胞密度增加, 临界成核半径降低, 同时加剧了热聚合反应, 导致胶质体的粘度增大, 不利于孔胞长大。发泡时间的延长会使热聚合更加充分, 影响胶质体粘度, 进而影响孔结构。

Tailoring of Pore Structure of Coal-based Carbon Foam

Vitrinite-concentration of fat coal was used as precursor to prepare carbon foams by nitrizing under high pressure. Influences of foaming temperature, pressure and time on the pore structure of carbon foams were investigated, whose prarameters include bulk density, porosity, morphology, pore cell average diameter, and the distribution of pore cell diameter and pore throats. The morphology of pore cell was observed by SEM. The distributions of pore cell diameters and pore throats as well as the mean diameter were calculated using analytical software of Nano Measurer 1.2. Results show that the nucleation of microcellular thermoplastic foam can qualitatively reveal the variable trend of pore cell structure of carbon foams. Rising of the foaming temperature results in nucleation volume density enhancement. Meanwhile, the rising temperature reduces the gas solubility in plastic mass, which is not conducive to the cell growth. Increasing foaming pressure leads to pore cell density enhancement, whereas the critical nucleation radius decrease. In addition, the increased foaming pressure exacerbates thermal polymerization reaction, increasing viscosity of the plastic mass, which is not conducive to the growth of pore cell. Extending foaming time enables thermal polymerization more sufficiently, which influences the viscosity of the plastic mass and further affects the pore structure.