2020-Tr?ger''''''''s Base (TB)-containing polyimide membranes derived from bio-based dianhydrides for gas separations
作者：XiaofanHu Won Hee Lee Jiayi Zhao Joon Yong Baea Ju Sung Kim Zhen Wang JinglingYan YongbingZhuang You
關(guān)鍵字：Tr?ger''''''''s Base (TB)-containing polyimide
論文來源：期刊
具體來源：Journal of Membrane Science
發(fā)表時(shí)間：2020年
Ultramicroporous polyimides obtained from bio-based anhydrides were
synthesized for gas separation. Two novel dianhydrides,
5,5''''''''-(mesitylmethylene)bis(4-methylphthalic anhydride) (MMDA) and
5,5''''''''-(9H-fluorene-9,9-diyl)bis(4-methylphthalic anhydride) (FDDA), were
successfully synthesized from guaiacol, a lignin-based bio-material. Due
to the fixed center of o-methyltriphenylmethane and o-methyldiphenylfluorene
units, the bio-based dianhydrides had high energy barriers to rotation,
resulting in highly rigid polymer chains. After polymerization with a
Tr?ger''''''''s Base (TB)-containing diamine using a one-step imidization, two
kinds of bio-based polyimides incorporating TB units (Bio-TBPI-1 and
Bio-TBPI-2) were prepared with reasonable molecular weights and
outstanding thermal properties. Bio-TBPIs demonstrated a microporous
structure determined by high BET surface areas of ～500?m3?g?1, high fractional free volumes (FFVs) of ～0.2, and d-spacings
of ～0.7. In addition, Bio-TBPIs exhibited narrow cavity size
distributions around 0.5?nm, and molecular sieving characteristics due
to the ultramicroporosity. Bio-TBPI membranes displayed excellent gas
separation performance, which was located near the upper bounds of
important gas pairs such as H2/CH4, H2/N2, O2/N2, and CO2/CH4.
The gas separation performance of Bio-TBPIs was better than that of
corresponding TB-based polyimides containing commercial dianhydrides.
The effect of physical aging on gas transport behaviors of Bio-TBPIs was
monitored for 200 days, resulting in loss of permeability and enhanced
selectivities.