【作者】 王秀月；

【导师】 王同华；

【作者基本信息】 大连理工大学 ， 化学工艺， 2007， 硕士

【摘要】 炭膜作为一种新型的无机膜是由含碳物质经过高温炭化而成的，与聚合物膜相比，炭膜具有较高的气体渗透能力和分离选择性，良好的热稳定性和化学稳定性，在气体分离方面展现出非常广阔的应用前景。但是由于用于制备炭膜的前驱体材料价格较高，增加了炭膜的制造成本，在一定程度上限制了与聚合物膜的竞争，有必要寻找一种廉价的前驱体材料来制备炭膜。聚糠醇是一种热固性聚合物，由于价格低廉，炭化后残炭量高，被认为是制备炭膜的理想前驱体材料。然而，目前用于制备炭膜的聚糠醇一般为聚合度大、粘度高的商业化产品，使用时需加溶剂稀释，并需经多次涂膜炭化过程才能成膜，制备工艺复杂，给大规模商业化应用带来很大的困难。因此，寻找一种制备低粘度的聚糠醇的方法，以便简化炭膜的制备工艺，降低炭膜的制造成本，已成为早日实现聚糠醇基炭膜的商业化应用的关键。本论文分别采用草酸和碘为催化剂，使糠醇单体在温和的条件下直接聚合成低粘度聚糠醇液体作为涂膜液，在煤基炭管支撑体上一次涂膜成功的制备出分离性能优良的气体分离炭膜。并通过考察制备过程中各影响因素如炭化终温、恒温时间等对炭膜分离性能的影响，进一步优化了制膜工艺，并且借助于热重分析（TG）、红外光谱（FTIR）、x射线衍射（XRD）、扫描电镜（SEM）和泡压法分析方法考察了聚糠醇热解过程中微结构的变化及前驱体分子结构对炭膜气体分离性能的影响。确定聚糠醇前驱体的分子结构与气体分离性能之间的内在关系。结果表明：在热解过程中，以草酸和碘为催化剂合成的两种结构的聚糠醇前驱体都是通过脱氧、重排、环化、芳构化等热分解和热缩聚反应逐渐转化为无定型的乱层炭结构，热分解趋势基本一致，但是热分解反应过程有明显不同，所形成炭膜的微结构也有很大的差异。聚糠醇的化学结构直接影响最终制备的复合炭膜的分离性能。其中以草酸为催化剂聚合得到的聚糠醇的交联程度较高，在热解过程中化学结构相对稳定，作为前驱体时制备的炭膜的选择性高，H₂／N₂、CO₂／N₂、O₂／N₂和CO₂／CH₄的分离系数可达到469.09、60.55、13.09和158.57。更多还原

【Abstract】 Carbon membranes prepared by carbonization of carbonaceous materials, as novelporous inorganic membranes, have been widely applied in many industrial fields due to theirhigh mechanical strength, thermal and chemical stability in non-oxidizing atmosphere.However, most of precursors for preparing carbon membrane are commercially expensive,which may greatly limit the commercial competition with organic membranes. It is necessaryto find out a low cost precursor to prepare carbon membranes. Poly （furfuryl alcohol）（PFA）has several advantages as the precursor for preparing the carbon membranes such as low costand high residual carbon. Unfortunately, the PFA used to prepare the carbon membranes hasthe high viscosity and polymerization degree which make the preparing procedure morecomplex by repeatly coating with dilute solution. Therefore, it is necessary to look for a newway to obtain a liquid PFA to simplify the preparing procedure.Liquid PFA as precursor was synthesized with different catalysts （oxalic acid and iodine）to prepare tubular C/CMS composite membranes in the thesis. Effect of carbonizationtemperature and the thermal soak time and test conditions were investigated. TG, FTIR,XRD and SEM were employed to characterize the PFA microstructure and the gas separationperformance of carbon membranes.The results show that the PFA synthesized by oxalic acid and iodine are transformed toturbostratic carbon structure from cross-linking polymeric structure by a series of reactionssuch as cyclization and aromatization during pyrolysis. Although they followed similarpyrolysis behavior, the chemical reaction and the resultant microstructure of carbonmembranes are different. Molecular structures of PFA have effect on the microstructure andgas separation performance of carbon membranes. Especially, the PFA catalyzed by oxalichad high thermal stability owing to its high cross-link degree. The resulting composite carbonmembranes showed superior permselectivity for gas pairs such as H₂/N₂, CO₂/N₂, O₂/N₂ andCO₂/CH₄, and the highest permselectivity were 469.09, 60.55, 13.09 and 158.57 at 25℃,respectively.更多还原