Effect of the chemical structure of various diamines on the gas separation of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes

Chye Yang Soo, Hye Jin Jo, Young Moo Lee, Jeffrey R. Quay, M. Keith Murphy

Research output: Contribution to journalArticle

39 Citations (Scopus)

Abstract

We investigated the effects of the polymer chemical structure on the gas separation performances of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes. Eight non-TR-able aromatic diamines, one TR-able hydroxyl diamine, and one dianhydride were utilized to synthesize precursors of TR-PBO-co-I. For comparison, a thermally rearranged (TR) polybenzoxazole (PBO) homopolymer precursor was also synthesized from the same type of dianhydride and hydroxy diamine. All precursors were fabricated into membranes and thermally treated in the solid state to produce TR-PBO-co-I/TR-PBO membranes. It was confirmed that the non-polar bulky side groups in the diamines disrupted polymer chain packing and increased the fractional free volume ( FFV) most effectively, resulting in increased gas permeabilities. A significant increase of the polymer rotational mobility imposed by the non-TR-able diamines promoted higher chain rotational motion which resulted in higher gas permeabilities. The percentage of conversion, which should affect the gas permeabilities, was very similar in all TR-PBO-co-I/TR-PBO membranes. Therefore, it was not a main factor in influencing the gas permeability of the TR-PBO-co-I/TR-PBO membranes. The gas selectivities of small gas molecules were improved if the non-TR-able diamines had a somewhat flat and rigid structure. The gas selectivities were also found to be much higher in the TR-PBO-co-I copolymer membranes compared to the TR-PBO homopolymer membrane.

Original languageEnglish
Pages (from-to)365-377
Number of pages13
JournalJournal of Membrane Science
Volume444
DOIs
StatePublished - 2013 Oct 1

Fingerprint

Benzoxazoles
Imides
Diamines
imides
diamines
Gases
Gas permeability
membranes
Membranes
gases
Permeability
permeability
Polymers
Homopolymerization
polymers
Rigid structures
selectivity
Free volume
Hydroxyl Radical
rigid structures

Keywords

  • Fractional free volume
  • Polybenzoxazole
  • Polybenzoxazole-co-imide
  • Polyimide
  • Thermally rearranged

Cite this

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title = "Effect of the chemical structure of various diamines on the gas separation of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes",
abstract = "We investigated the effects of the polymer chemical structure on the gas separation performances of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes. Eight non-TR-able aromatic diamines, one TR-able hydroxyl diamine, and one dianhydride were utilized to synthesize precursors of TR-PBO-co-I. For comparison, a thermally rearranged (TR) polybenzoxazole (PBO) homopolymer precursor was also synthesized from the same type of dianhydride and hydroxy diamine. All precursors were fabricated into membranes and thermally treated in the solid state to produce TR-PBO-co-I/TR-PBO membranes. It was confirmed that the non-polar bulky side groups in the diamines disrupted polymer chain packing and increased the fractional free volume ( FFV) most effectively, resulting in increased gas permeabilities. A significant increase of the polymer rotational mobility imposed by the non-TR-able diamines promoted higher chain rotational motion which resulted in higher gas permeabilities. The percentage of conversion, which should affect the gas permeabilities, was very similar in all TR-PBO-co-I/TR-PBO membranes. Therefore, it was not a main factor in influencing the gas permeability of the TR-PBO-co-I/TR-PBO membranes. The gas selectivities of small gas molecules were improved if the non-TR-able diamines had a somewhat flat and rigid structure. The gas selectivities were also found to be much higher in the TR-PBO-co-I copolymer membranes compared to the TR-PBO homopolymer membrane.",
keywords = "Fractional free volume, Polybenzoxazole, Polybenzoxazole-co-imide, Polyimide, Thermally rearranged",
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language = "English",
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Effect of the chemical structure of various diamines on the gas separation of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes. / Soo, Chye Yang; Jo, Hye Jin; Lee, Young Moo; Quay, Jeffrey R.; Murphy, M. Keith.

In: Journal of Membrane Science, Vol. 444, 01.10.2013, p. 365-377.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of the chemical structure of various diamines on the gas separation of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes

AU - Soo, Chye Yang

AU - Jo, Hye Jin

AU - Lee, Young Moo

AU - Quay, Jeffrey R.

AU - Murphy, M. Keith

PY - 2013/10/1

Y1 - 2013/10/1

N2 - We investigated the effects of the polymer chemical structure on the gas separation performances of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes. Eight non-TR-able aromatic diamines, one TR-able hydroxyl diamine, and one dianhydride were utilized to synthesize precursors of TR-PBO-co-I. For comparison, a thermally rearranged (TR) polybenzoxazole (PBO) homopolymer precursor was also synthesized from the same type of dianhydride and hydroxy diamine. All precursors were fabricated into membranes and thermally treated in the solid state to produce TR-PBO-co-I/TR-PBO membranes. It was confirmed that the non-polar bulky side groups in the diamines disrupted polymer chain packing and increased the fractional free volume ( FFV) most effectively, resulting in increased gas permeabilities. A significant increase of the polymer rotational mobility imposed by the non-TR-able diamines promoted higher chain rotational motion which resulted in higher gas permeabilities. The percentage of conversion, which should affect the gas permeabilities, was very similar in all TR-PBO-co-I/TR-PBO membranes. Therefore, it was not a main factor in influencing the gas permeability of the TR-PBO-co-I/TR-PBO membranes. The gas selectivities of small gas molecules were improved if the non-TR-able diamines had a somewhat flat and rigid structure. The gas selectivities were also found to be much higher in the TR-PBO-co-I copolymer membranes compared to the TR-PBO homopolymer membrane.

AB - We investigated the effects of the polymer chemical structure on the gas separation performances of thermally rearranged poly(benzoxazole-co-imide) (TR-PBO-co-I) membranes. Eight non-TR-able aromatic diamines, one TR-able hydroxyl diamine, and one dianhydride were utilized to synthesize precursors of TR-PBO-co-I. For comparison, a thermally rearranged (TR) polybenzoxazole (PBO) homopolymer precursor was also synthesized from the same type of dianhydride and hydroxy diamine. All precursors were fabricated into membranes and thermally treated in the solid state to produce TR-PBO-co-I/TR-PBO membranes. It was confirmed that the non-polar bulky side groups in the diamines disrupted polymer chain packing and increased the fractional free volume ( FFV) most effectively, resulting in increased gas permeabilities. A significant increase of the polymer rotational mobility imposed by the non-TR-able diamines promoted higher chain rotational motion which resulted in higher gas permeabilities. The percentage of conversion, which should affect the gas permeabilities, was very similar in all TR-PBO-co-I/TR-PBO membranes. Therefore, it was not a main factor in influencing the gas permeability of the TR-PBO-co-I/TR-PBO membranes. The gas selectivities of small gas molecules were improved if the non-TR-able diamines had a somewhat flat and rigid structure. The gas selectivities were also found to be much higher in the TR-PBO-co-I copolymer membranes compared to the TR-PBO homopolymer membrane.

KW - Fractional free volume

KW - Polybenzoxazole

KW - Polybenzoxazole-co-imide

KW - Polyimide

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