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摘要
以3,3′,4,4′-联苯四甲酸二酐(BPDA)和2,4,6-三甲基间苯二胺(TrMPD)为单体,采用两步法合成了一种聚酰亚胺(PI),并通过红外光谱对其结构进行了表征。以所制PI的四氯乙烷(TCE)溶液为铸膜液,甲醇为凝固浴溶剂,采用相转化法制得了一系列非对称膜(皮层厚度:3.4～5.7μm),并研究了不同制膜工艺条件对膜的形貌结构和性能的影响规律。结果表明:所制得的非对称膜具有良好的力学性能(拉伸强度28.9～40.9MPa,断裂伸长率38.9%～87.5%)和较高的二氧化碳通量[35℃,2atm,11.4～25.8GPU,1GPU=10-6cm3(STP)/(cm2·s·cmHg)]。气体透过选择性与膜的皮层缺陷控制密切相关,由5% PI溶液先在60℃下干燥35min,再在甲醇凝固浴中浸泡5min所制得的非对称膜的皮层高度致密,其气体透过选择性(PO2/PN2=4.10,PCO2/PN2=22.3,PCO2/PCH4=23.0)与均质膜一致。
Abstract
A polyimide (PI) was synthesized from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 2,4,6-trimethyl-1,3-phenylene (TrMPD) via a two-step procedure and the resulting polymer was characterized by FT-IR spectrum.A series of asymmetric membranes (thickness of skin layer:3.4～5.7μm) were prepared via the phase inversion method using 1,1,2,2-tetrachloroethane (TCE) for dissolution of the PI and methanol for coagulation of the PI cast solution.The effect of membrane fabrication conditions on their morphology and properties was investigated.The prepared membranes exhibited good mechanical properties (tensile strength:28.9～40.9MPa,elongation at break:38.9%～87.5%) and reasonably high CO2 permeance [35℃,2atm,11.4～25.8GPU,1GPU=10-6cm3(STP)/(cm2·s·cmHg)].The permselectivity was closely related to the defect control of the skin layer,and the asymmetric membrane prepared by drying the 5% PI cast solution at 60℃ for 35min followed by coagulated in methanol for 5 min displayed similar pemselectivity (PO2/PN2=4.10,PCO2/PN2=22.3,PCO2/PCH4=23.0) to that of the corresponding dense membrane due to its defect-free skin layer.
关键词
聚酰亚胺
/
非对称膜
/
气体分离
Key words
polyimide
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asymmetric membrane
/
gas separation
聚酰亚胺非对称膜的制备及其气体分离性能[J].
化工新型材料, 2020, 48(3): 37-40 DOI:
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基金资助
科技部九七三项目(2014CB643600)
