TY - JOUR
T1 - Polyimide-SiO2-TiO2 nanocomposite structural study probing free volume, physical properties, and gas transport
AU - Huang, Fei
AU - Cornelius, Chris J.
N1 - Funding Information:
The author would like to thank Dr. Chen in UNL for his help with the TEM microscopy. Sol-gel efforts were partially supported by NSF grant CMMI-1562822.
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017
Y1 - 2017
N2 - Polyimide-SiO2-TiO2 nanocomposite membrane permeability, diffusivity, and selectivity were evaluated using polyimide block copolymers designed from 6F and [6F-DABA], and [SiO2-TiO2] using He, H2, CO2, O2, N2, and CH4. Nanocomposite membranes were synthesized using an in-situ sol-gel method to improve the integration of inorganic and organic phases. Metal alkoxide type and polymer functional groups were key factors affecting physical properties and gas transport. [6F-DABA]-[SiO2-TiO2] nanocomposite fractional free volume (FFV) increased 29% as compared to the unmodified [6F-DABA] polyimide. Dynamic Mechanical Thermal Analysis revealed that [SiO2-TiO2] and [TiO2] within functionalized multi-block reduced chain mobility. This led to a Tg increase from 334 °C to 359 °C, and tanδ to decrease from 1.9 to 0.35. In general, inorganic concentration and composition retarded polymer segmental motions, inhibited polymer chain packing, and increase predicted FFV. [6F-DABA-50]-[SiO2-TiO2] membrane's exhibited a simultaneous gas selectivity and permeability improvement. He permeability improved from 58 (unmodified polyimide) to 83 Barrers, and He/CH4 gas selectivity increased from 221 (unmodified) to 334. Membrane gas separation performance of several organic-inorganic materials exceeded Robeson's “upper bound.”
AB - Polyimide-SiO2-TiO2 nanocomposite membrane permeability, diffusivity, and selectivity were evaluated using polyimide block copolymers designed from 6F and [6F-DABA], and [SiO2-TiO2] using He, H2, CO2, O2, N2, and CH4. Nanocomposite membranes were synthesized using an in-situ sol-gel method to improve the integration of inorganic and organic phases. Metal alkoxide type and polymer functional groups were key factors affecting physical properties and gas transport. [6F-DABA]-[SiO2-TiO2] nanocomposite fractional free volume (FFV) increased 29% as compared to the unmodified [6F-DABA] polyimide. Dynamic Mechanical Thermal Analysis revealed that [SiO2-TiO2] and [TiO2] within functionalized multi-block reduced chain mobility. This led to a Tg increase from 334 °C to 359 °C, and tanδ to decrease from 1.9 to 0.35. In general, inorganic concentration and composition retarded polymer segmental motions, inhibited polymer chain packing, and increase predicted FFV. [6F-DABA-50]-[SiO2-TiO2] membrane's exhibited a simultaneous gas selectivity and permeability improvement. He permeability improved from 58 (unmodified polyimide) to 83 Barrers, and He/CH4 gas selectivity increased from 221 (unmodified) to 334. Membrane gas separation performance of several organic-inorganic materials exceeded Robeson's “upper bound.”
KW - 6FDA (6F) and 6FDA-DABA (6F-DABA) Polyimide
KW - Gas transport
KW - Organic-Inorganic nanocomposite
KW - Physical properties
KW - SiO and TiO Sol-gel Chemistry
UR - http://www.scopus.com/inward/record.url?scp=85026906623&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85026906623&partnerID=8YFLogxK
U2 - 10.1016/j.memsci.2017.08.003
DO - 10.1016/j.memsci.2017.08.003
M3 - Article
AN - SCOPUS:85026906623
SN - 0376-7388
VL - 542
SP - 110
EP - 122
JO - Journal of Membrane Science
JF - Journal of Membrane Science
ER -