碳化法制备酚醛树脂基微滤碳膜

以高含碳热塑性酚醛树脂为原料，通过碳化制备了酚醛树脂基微滤碳膜，考察了碳化条件，包括碳化终温、升温速率、恒温时间和保护气流速对膜的平均孔径、孔径分布和气体透量的影响. 对碳膜进行了CO2活化处理，考察了活化条件对碳膜性能的影响. 用热重分析考察了碳膜碳化失重，用泡点法测量了其孔径分布. 实验结果表明，随着碳化终温的升高，碳膜的平均孔径和气体透量均减小，当碳化终温从650℃升高到950℃时，碳膜的平均孔径从0.61 mm下降到0.54 mm，气体透量从1.84′10-5 mol/(m2×s×Pa)下降到1.14′10-5 mol/(m2×s×Pa). 350℃碳化温度得到的碳膜爆破强度最低，随着碳化温度的升高爆破强度增加. 升温速率、恒温时间和保护气流速对碳膜性能影响不大. 活化导致膜孔径变大，当CO2浓度从12.5%增加到50%时，碳膜的平均孔径从1.54 mm增大到1.96 mm，气体透量从7.0′10-5 mol/(m2×s×Pa)增大到1.68′10-4 mol/(m2×s×Pa).

Preparation of Microfiltration Carbon Membrane by Pyrolysis of Phenol-Formaldehyde Resin

The microfiltration carbon membrane was prepared by pyrolysis of novolac phenol-formaldehyde resin. The effects of carbonization conditions, including carbonization temperature, heating rate, holding time and protective gas flow rate, and activation conditions on the carbon membrane properties were systematically investigated. The mass loss during carbonization was characterized by thermogravimetric analysis. The gas bubble pressure method was used to determine the pore size distribution of the carbon membrane. The results indicate that the gas permeation rate and the mean pore size of carbon membrane decrease with the increase of carbonization temperature. The gas permeation rate decreases from 1.84′10-5 mol/(m2×s×Pa) to 1.14′10-5 mol/(m2×s×Pa) and the mean pore size decreases from 0.61 mm to 0.54 mm with the carbonization temperature from 650℃ to 950℃. The carbon membrane carbonized at 350℃ shows the lowest strength. Above 350℃, high carbonization temperature results in high strength carbon membrane. The heating rate, holding time and protective gas flow rate have little effect on the carbon membrane properties. Activation of carbon membrane with CO2 increases the pore size of membrane. With CO2 content increasing from 12.5% to 50%, the gas permeation rate increases from 7.0′10-5 mol/(m2×s×Pa) to 1.68′10-4 mol/(m2×s×Pa) and the mean pore size increases from 1.54 mm to 1.96 mm.