Synergistic effect of thermal crosslinking and thermal rearrangement on free volume and gas separation properties of 6FDA based polyimide membranes studied by positron annihilation

2021 ◽  
pp. 120163
Author(s):  
Jingjing Kong ◽  
Junjie Liu ◽  
Peiyu Jia ◽  
Ning Qi ◽  
Zhiquan Chen ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Positron Annihilation ◽  
Free Volume ◽  
Gas Separation ◽  
Thermal Rearrangement ◽  
Thermal Crosslinking ◽  
Polyimide Membranes

Tuning the Free Volume Cavities of Polyimide Membranes via the Construction of Pseudo-Interpenetrating Networks for Enhanced Gas Separation Performance

2009 ◽  
Vol 42 (18) ◽  
pp. 7042-7054 ◽  
Author(s):  
Bee Ting Low ◽  
Tai Shung Chung ◽  
Hongmin Chen ◽  
Yan-Ching Jean ◽  
Kumari Pallathadka Pramoda
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Separation Performance ◽  
Interpenetrating Networks ◽  
Gas Separation Performance ◽  
Polyimide Membranes

Synthesis and characterization of triptycene-based polyimides with tunable high fractional free volume for gas separation membranes

2014 ◽  
Vol 2 (33) ◽  
pp. 13309-13320 ◽  
Author(s):  
Jennifer R. Wiegand ◽  
Zachary P. Smith ◽  
Qiang Liu ◽  
Christopher T. Patterson ◽  
Benny D. Freeman ◽  
...  
Keyword(s):  
Free Volume ◽  
Gas Separation ◽  
Gas Transport ◽  
Synthesis And Characterization ◽  
Fractional Free Volume ◽  
Separation Membranes ◽  
Gas Separation Membranes ◽  
Selective Separations ◽  
Polyimide Membranes

Triptycene-containing polyimide membranes with tunable fractional free volume promoting fast gas transport and selective separations.

Preliminary Positron Lifetime Results on Free Volumes in Cyclodextrins

2010 ◽  
Vol 666 ◽  
pp. 99-102 ◽  
Author(s):  
Maria Fatima Ferreira Marques ◽  
A.M.G. Moreira Da Silva ◽  
P.M. Gordo ◽  
Z. Kajcsos
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Lifetime ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Source ◽  
Lifetime Component ◽  
Positron Annihilation Lifetime ◽  
Long Lifetime

Positron annihilation lifetime spectroscopy was used to study the free-volume parameters in various pure -, - and -cyclodextrins samples and, in the case of β-cyclodextrin, with inclusion of S-carvone and thymoquinone. The results clearly indicate the presence of long lifetime components related to Ps-formation. The data show that the addition of S-carvone to β-cyclodextrin results in a decrease of o-Ps lifetime that we ascribe to a reduction of free volume holes from 81.8 to 63.7 Å3. The long lifetime component disappears when thymoquinone is added to -cyclodextrin, indicating this substance acts as an o-Ps quencher. For all samples studied, a decrease in the long lifetime component values was observed with increasing source in situ time, a result that might be attributed to the irradiation of the sample by the 22Na positron source.

scholarly journals Free-volume Characterization of Polysilanes Using Positron Annihilation Spectroscopy.

1999 ◽  
Vol 12 (5) ◽  
pp. 739-742
Author(s):  
Mutsumi Tashiro ◽  
Shu Seki ◽  
Pradeep K. Pujari ◽  
Yoshihide Honda ◽  
Seiichi Tagawa
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Positron Annihilation Spectroscopy

Ceramide increases free volume voids in DPPC membranes

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44282-44290 ◽  
Author(s):  
E. Axpe ◽  
A. B. García-Arribas ◽  
J. I. Mujika ◽  
D. Mérida ◽  
A. Alonso ◽  
...  
Keyword(s):  
Positron Annihilation ◽  
Free Volume ◽  
Lipid Membranes ◽  
Positron Annihilation Lifetime Spectroscopy ◽  
Positron Annihilation Lifetime

We have measured by positron annihilation lifetime spectroscopy (PALS) that ceramide increases the size of the free volume holes in DPPC lipid membranes.

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