聚丙烯腈基炭膜制备及结构变化的研究

Study on preparation and structure change of carbon membrane with polyacrylonitrile precursor

采用TG、FTIR及XRD法对PAN基炭膜在制备过程中结构变化进行了研究。结果表明 ,PAN原膜的热解过程主要分三个阶段 :第一阶段是脱水和溶剂挥发阶段 ;第二阶段为PAN的分解阶段 ,发生了环化、交联、链断裂反应 ;第三阶段时 ,分子链间的交联反应程度进一步深化 ,并向层面网状结构转变 ,形成的炭膜属于无定性碳结构。热解过程中小分子气体的析出 ,有利于孔隙结构的形成 。

The changes of structure of carbon membrane with polyacrylonitrile (PAN) precursor were studied by TG、FTIR and XRD analysis during the pyrolysis processes. The results show that the pyrolysis process of PAN includes three stages. In the early stage of heating, dehydrationand and solvent volatilization are significant, and then three kinds of reactions, cyclization, crosslinkling and cleavage of liner PAN chain uptake are found to occur in second stage, finally the crosslinking degree of molecular chain increases and transforms into ladder shaped reticular structure. The evolution of gases during the pyrolysis is beneficial to the formation of micropore structure of carbon membrane. It indicated that PAN is a good precursor for preparing a high performance carbon membrane.