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Tai-shung Chung - One of the best experts on this subject based on the ideXlab platform.
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Formation of defect‐free polyetherimide/PIM‐1 hollow fiber membranes for gas separation
Aiche Journal, 2014Co-Authors: Tai-shung ChungAbstract:Dual-layer hollow fiber membranes were produced from blends of Ultem and polymer of intrinsic microporosity (PIM-1) with enhanced gas permeance. The effects of spinning parameters (take-up speed and air gap distance) on gas separation performance were investigated based on the pristine Ultem. Selected spinning conditions were further adopted for the blend system, achieving defect-free and almost defect-free hollow fibers. Adding PIM results in a higher fractional free volume, 50% increments in gas permeance were observed for Ultem/PIM-1 (95/5) and more than 100% increments for Ultem/PIM-1 (85/15). Both O2/N2 and CO2/CH4 selectivities remained the same for Ultem/PIM-1 (95/5) and above 80% of their respective intrinsic values for Ultem/PIM-1 (85/15). The selective layer thickness ranges from 70 to 120 nm, indicating the successful formation of ultrathin dense layers. Moreover, minimum amounts of the expensive material were consumed, that is, 0.88, 1.7, and 2.3 wt % PIM-1 for Ultem/PIM-1 (95/5), (90/10), and (85/15), respectively. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3848–3858, 2014
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pim 1 as an organic filler to enhance the gas separation performance of Ultem polyetherimide
Journal of Membrane Science, 2014Co-Authors: Pei Li, Tai-shung ChungAbstract:Abstract An assortment of Ultem/PIM-1 polymer blends was prepared and their transport properties to a series of gases were studied. Good dispersion between the PIM-1 and Ultem phases was found when the PIM-1 loading was low ( 90 wt%). A slight shift of T g was observed when the PIM-1 loading increased from 0 wt% to 50 wt%, suggesting likely partially miscibility. The molecular-level interactions were further confirmed by the FTIR and XRD data, where shifts of peaks were detected at several compositions. Gas transport properties of pure gases including He, N 2 , O 2 , CH 4 , CO 2 for all polymer blends and mixed gases including CO 2 /CH 4 (50/50) and CO 2 /N 2 (50/50) gas pairs for Ultem/PIM-1 (90:10) and Ultem/PIM-1 (80:20) blends were explored. Considerable increments in gas permeability were observed by adding only 5 or 10 wt% PIM-1 without much compromising gas pair selectivity, i.e., the CO 2 permeability increased impressively over 47% and 167%, respectively, compared with the pristine Ultem. When comparing the gas permeation properties with the predictions from semi-logarithm and Maxwell equations, they follow nicely with the semi-logarithm addition when the PIM-1 loadings are low ( 90 wt%) due to the good dispersion of Ultem inside PIM-1. This study opens up the potential of employing PIM-1 as an organic filler to improve the permeability of low permeable materials for other industrial membrane applications.
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pervaporation dehydration of c2 c4 alcohols by 6fda oda nda Ultem dual layer hollow fiber membranes with enhanced separation performance and swelling resistance
Chemical Engineering Journal, 2009Co-Authors: Natalia Widjojo, Tai-shung ChungAbstract:Abstract A novel copoly(4,4′-diphenyleneoxide/1,5-napthalene-2,2′-bis (3,4-dicarboxyl phenyl) hexa fluoro propane diimide) 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane for pervaporation dehydration has been fabricated via co-extrusion process. Not only can it achieve impressive alcohol dehydration performance without any post-treatment but also it particularly minimizes the membrane's swelling behavior towards aqueous alcohol solution. For isopropanol, n-butanol and t-butanol dehydrations of 85/15 (alcohol/water) wt.% feed solutions, the 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane can successfully attain permeate containing more than 99.7 wt.% water with considerably high flux which implies to a distinctive separation factor of the respective alcohol system. The outstanding dehydration performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes on various aqueous alcohol feeds can be attributed to: (1) a precise formulation of the outer- and inner-layer dope compositions; (2) the size of d -space created in the outer-layer is a good match for size exclusion mechanism in the alcohol dehydration systems; (3) a relatively low water uptake and less swelling characteristics of the Ultem ® 1010 polyimide as a supporting layer. By adjusting spinning parameters, i.e. outer-layer dope flow rate and air gap distance, the separation performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes can be further improved.
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Pervaporation dehydration of C2–C4 alcohols by 6FDA-ODA-NDA/Ultem® dual-layer hollow fiber membranes with enhanced separation performance and swelling resistance
Chemical Engineering Journal, 2009Co-Authors: Natalia Widjojo, Tai-shung ChungAbstract:Abstract A novel copoly(4,4′-diphenyleneoxide/1,5-napthalene-2,2′-bis (3,4-dicarboxyl phenyl) hexa fluoro propane diimide) 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane for pervaporation dehydration has been fabricated via co-extrusion process. Not only can it achieve impressive alcohol dehydration performance without any post-treatment but also it particularly minimizes the membrane's swelling behavior towards aqueous alcohol solution. For isopropanol, n-butanol and t-butanol dehydrations of 85/15 (alcohol/water) wt.% feed solutions, the 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane can successfully attain permeate containing more than 99.7 wt.% water with considerably high flux which implies to a distinctive separation factor of the respective alcohol system. The outstanding dehydration performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes on various aqueous alcohol feeds can be attributed to: (1) a precise formulation of the outer- and inner-layer dope compositions; (2) the size of d -space created in the outer-layer is a good match for size exclusion mechanism in the alcohol dehydration systems; (3) a relatively low water uptake and less swelling characteristics of the Ultem ® 1010 polyimide as a supporting layer. By adjusting spinning parameters, i.e. outer-layer dope flow rate and air gap distance, the separation performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes can be further improved.
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Synthesis and Properties of Fluoro-Polyetherimides
Polymer Engineering and Science, 2000Co-Authors: Rohitkumar H. Vora, Tai-shung ChungAbstract:A series of amorphous fluoro-polyetherimides based on 2,2'-bis(3,4-dicarboxyphenyl) hexafluropropane dianhydride (6FDA) and di-ether-containing diamines 4,4'-bis(3-aminophenoxy)diphenyl sulfone (m-SED), 4,4'-bis(4-aminophenoxy)diphenyl sulfone (pSED), 4,4-bis(4-aminophenoxy)diphenyl propane (BPADE) were synthesized. These melt processable polyetherimide polymers from pSED and BPADE showed excellent electrical properties. The dielectric constants, 2.74 and 2.65 at 10 MHz respectively, are lower than commercially available polyetherimide Ultem@ 1000, and polyimide Kapton@ H films. In addition, we found that trifluoromethyl groups-containing polyimides not only show extraordinaxy electrical properties, but they also exhibit excellent long-term thermo-oxidative stability and reduced water absorption relative to non-fluorinated polyimides. The weight retention of these fluoro-polyetherimides at 3 15°C for 300 h in air varies from 93% to 98%. Whereas, their moisture absorption at 100 RH at 50°C was in the range of 0.3% to 1.05%, which is much lower than those of Ultem 1000 and Kapton H. In the case of fluoro-polyetherimides from pSED and m-SED @ara and meta isomers) diamines with 'ether' and sulfonyl (-SO,-) spacer groups, the d-spacing and Tg values decreased from 4.7d to 4.56A and 293°C to 244°C respectively. Similarly, the transparency of these polymer films (in the range of 80% to 90%) at 500 nm solar wavelength was higher than Ultem 1000 and Kapton H. 1. I"R0DUCTION romatic polyimides possess outstanding thermal A mechanical and electrical properties as well as excellent chemical resistance (1). The search for new polyimides with improved processability and higher glass transition temperatures (TJ than the commercially available polyetherimide Ultem 1000 has received significant attention from both academia and industries. It is also known that structural rigidity of dianhydrides contributes to the increase in the glass transition temperatures of those polyimides in the range of 300 to 400°C. Therefore, because of their poor solubility in common organic solvents and high softening temperatures, uses of these polymers in industrial applications are limited. Because of these
William J Macknight - One of the best experts on this subject based on the ideXlab platform.
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Fourier transform infra-red spectroscopy on the thermo-oxidative degradation of polybenzimidazole and of a polybenzimidazole/polyetherimide blend
Polymer, 2003Co-Authors: P Musto, Frank E Karasz, William J MacknightAbstract:Abstract The thermo-oxidative degradation of the polybenzimidazole material, poly[2,2′-m-phenylene)-5,5′-bibenzimidazole] (PBI), and of a blend of PBI with the polyetherimide, poly[2,2′-bis(3,4-dicarboxyphenoxy) phenylpropane-2-phenylene bisimide] (Ultem 1000), was investigated by Fourier transform infra-red (FTi.r.) spectroscopy. An experimental protocol and the necessary instrumentation were developed for real-time monitoring of the molecular changes occurring during the process. The spectroscopic data provided information about the mechanism and the kinetics of the thermo-oxidative degradation in its early stages. The FTi.r. spectra of the PBI/Ultem 1000 blend were analysed by subtraction spectroscopy, and the application of this technique allowed us to selectively follow the fate of the two components in the blend. No chemical interaction between PBI and Ultem 1000 was detectable by FTi.r. spectroscopy during the degradation process.
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fourier transform infra red spectroscopy on the thermo oxidative degradation of polybenzimidazole and of a polybenzimidazole polyetherimide blend
Polymer, 1993Co-Authors: P Musto, Frank E Karasz, William J MacknightAbstract:Abstract The thermo-oxidative degradation of the polybenzimidazole material, poly[2,2′-m-phenylene)-5,5′-bibenzimidazole] (PBI), and of a blend of PBI with the polyetherimide, poly[2,2′-bis(3,4-dicarboxyphenoxy) phenylpropane-2-phenylene bisimide] (Ultem 1000), was investigated by Fourier transform infra-red (FTi.r.) spectroscopy. An experimental protocol and the necessary instrumentation were developed for real-time monitoring of the molecular changes occurring during the process. The spectroscopic data provided information about the mechanism and the kinetics of the thermo-oxidative degradation in its early stages. The FTi.r. spectra of the PBI/Ultem 1000 blend were analysed by subtraction spectroscopy, and the application of this technique allowed us to selectively follow the fate of the two components in the blend. No chemical interaction between PBI and Ultem 1000 was detectable by FTi.r. spectroscopy during the degradation process.
P Musto - One of the best experts on this subject based on the ideXlab platform.
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Fourier transform infra-red spectroscopy on the thermo-oxidative degradation of polybenzimidazole and of a polybenzimidazole/polyetherimide blend
Polymer, 2003Co-Authors: P Musto, Frank E Karasz, William J MacknightAbstract:Abstract The thermo-oxidative degradation of the polybenzimidazole material, poly[2,2′-m-phenylene)-5,5′-bibenzimidazole] (PBI), and of a blend of PBI with the polyetherimide, poly[2,2′-bis(3,4-dicarboxyphenoxy) phenylpropane-2-phenylene bisimide] (Ultem 1000), was investigated by Fourier transform infra-red (FTi.r.) spectroscopy. An experimental protocol and the necessary instrumentation were developed for real-time monitoring of the molecular changes occurring during the process. The spectroscopic data provided information about the mechanism and the kinetics of the thermo-oxidative degradation in its early stages. The FTi.r. spectra of the PBI/Ultem 1000 blend were analysed by subtraction spectroscopy, and the application of this technique allowed us to selectively follow the fate of the two components in the blend. No chemical interaction between PBI and Ultem 1000 was detectable by FTi.r. spectroscopy during the degradation process.
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fourier transform infra red spectroscopy on the thermo oxidative degradation of polybenzimidazole and of a polybenzimidazole polyetherimide blend
Polymer, 1993Co-Authors: P Musto, Frank E Karasz, William J MacknightAbstract:Abstract The thermo-oxidative degradation of the polybenzimidazole material, poly[2,2′-m-phenylene)-5,5′-bibenzimidazole] (PBI), and of a blend of PBI with the polyetherimide, poly[2,2′-bis(3,4-dicarboxyphenoxy) phenylpropane-2-phenylene bisimide] (Ultem 1000), was investigated by Fourier transform infra-red (FTi.r.) spectroscopy. An experimental protocol and the necessary instrumentation were developed for real-time monitoring of the molecular changes occurring during the process. The spectroscopic data provided information about the mechanism and the kinetics of the thermo-oxidative degradation in its early stages. The FTi.r. spectra of the PBI/Ultem 1000 blend were analysed by subtraction spectroscopy, and the application of this technique allowed us to selectively follow the fate of the two components in the blend. No chemical interaction between PBI and Ultem 1000 was detectable by FTi.r. spectroscopy during the degradation process.
Natalia Widjojo - One of the best experts on this subject based on the ideXlab platform.
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pervaporation dehydration of c2 c4 alcohols by 6fda oda nda Ultem dual layer hollow fiber membranes with enhanced separation performance and swelling resistance
Chemical Engineering Journal, 2009Co-Authors: Natalia Widjojo, Tai-shung ChungAbstract:Abstract A novel copoly(4,4′-diphenyleneoxide/1,5-napthalene-2,2′-bis (3,4-dicarboxyl phenyl) hexa fluoro propane diimide) 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane for pervaporation dehydration has been fabricated via co-extrusion process. Not only can it achieve impressive alcohol dehydration performance without any post-treatment but also it particularly minimizes the membrane's swelling behavior towards aqueous alcohol solution. For isopropanol, n-butanol and t-butanol dehydrations of 85/15 (alcohol/water) wt.% feed solutions, the 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane can successfully attain permeate containing more than 99.7 wt.% water with considerably high flux which implies to a distinctive separation factor of the respective alcohol system. The outstanding dehydration performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes on various aqueous alcohol feeds can be attributed to: (1) a precise formulation of the outer- and inner-layer dope compositions; (2) the size of d -space created in the outer-layer is a good match for size exclusion mechanism in the alcohol dehydration systems; (3) a relatively low water uptake and less swelling characteristics of the Ultem ® 1010 polyimide as a supporting layer. By adjusting spinning parameters, i.e. outer-layer dope flow rate and air gap distance, the separation performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes can be further improved.
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Pervaporation dehydration of C2–C4 alcohols by 6FDA-ODA-NDA/Ultem® dual-layer hollow fiber membranes with enhanced separation performance and swelling resistance
Chemical Engineering Journal, 2009Co-Authors: Natalia Widjojo, Tai-shung ChungAbstract:Abstract A novel copoly(4,4′-diphenyleneoxide/1,5-napthalene-2,2′-bis (3,4-dicarboxyl phenyl) hexa fluoro propane diimide) 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane for pervaporation dehydration has been fabricated via co-extrusion process. Not only can it achieve impressive alcohol dehydration performance without any post-treatment but also it particularly minimizes the membrane's swelling behavior towards aqueous alcohol solution. For isopropanol, n-butanol and t-butanol dehydrations of 85/15 (alcohol/water) wt.% feed solutions, the 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membrane can successfully attain permeate containing more than 99.7 wt.% water with considerably high flux which implies to a distinctive separation factor of the respective alcohol system. The outstanding dehydration performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes on various aqueous alcohol feeds can be attributed to: (1) a precise formulation of the outer- and inner-layer dope compositions; (2) the size of d -space created in the outer-layer is a good match for size exclusion mechanism in the alcohol dehydration systems; (3) a relatively low water uptake and less swelling characteristics of the Ultem ® 1010 polyimide as a supporting layer. By adjusting spinning parameters, i.e. outer-layer dope flow rate and air gap distance, the separation performance of 6FDA-ODA-NDA/Ultem ® 1010 dual-layer hollow fiber membranes can be further improved.
Maria J. Sanchis - One of the best experts on this subject based on the ideXlab platform.
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A relaxational and conductive study on two poly(ether imide)s
Polymer International, 2004Co-Authors: Maria J. Sanchis, Mathias Mudarra, J. Belana, J.a. Diego, J. C. Cañadas, R. Diaz Calleja, C. Jaimes, Joana SellaresAbstract:A study of the relaxations and the conductivity of poly(ether imide) (PEI) Ultem 5000 was carried out. The results were compared with the ones obtained in a previous study of PEI Ultem 1000. The glass transition temperature was determined by differential scanning calorimetry (DSC). Then, the relaxations of PEI Ultem 5000 using the thermally stimulated depolarization current technique (TSDC) on conventionally polarized electrets were studied. Owing to the interesting structure indicated by this technique a more detailed analysis of the β relaxation was done using window polarization (WP). It was possible to isolate 7 subrelaxations that we related to their counterparts in PEI Ultem 1000. WP was also used to compare, one by one, the other relaxations that both materials present. The analysis of the ρ relaxation showed that the space trapping capability is stronger in PEI Ultem 5000. The role of conductivity was analyzed using open circuit polarized samples and, more quantitatively, using dielectric analysis (DEA) and the dielectric modulus formalism. DEA and dynamic mechanical thermal analysis (DMTA) were also used to obtain information about the polar relaxations, complementary to that obtained by TSDC. Copyright © 2004 Society of Chemical Industry
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Space charge relaxation in polyetherimides by the electric modulus formalism
Journal of Applied Physics, 2000Co-Authors: Mathias Mudarra, J. Belana, J.a. Diego, Ricardo Díaz-calleja, Joana Sellares, J. C. Cañadas, Maria J. SanchisAbstract:Dynamic electrical analysis shows that at high temperatures (above the glass transition temperature), the electrical properties of polyetherimide are strongly influenced by space charge. In this article we have studied the relaxation of space charge in two commercial varieties of polyetherimide: Ultem 1000 and Ultem 5000. Their conductive properties were determined by dynamic electrical analysis, using the electric modulus formalism. The complex part of the electric modulus was fitted to Coelho’s model which considers ohmic conductivity and diffusion as the prevailing charge transport mechanisms. The complex part of the electric modulus exhibits a peak in the low frequency range that can be associated with space charge. A good agreement between experimental and calculated data is observed after the fitting process to Coelho’s model. Differences in the electrode behavior were required: blocking electrode conditions in the case of Ultem 5000 and partially blocking electrode for Ultem 1000. In both cases the...
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physical ageing studies in polyetherimide Ultem 1000
Polymer International, 1998Co-Authors: J. Belana, Mathias Mudarra, J. C. Cañadas, C. Jaimes, J A Diego, R Diaz, S Friederichs, Maria J. SanchisAbstract:Thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry (DSC) have been used to study the effect of physical ageing in polyetherimide (PEI: Ultem 1000®). Ageing temperatures (T a ) between 48 and 8°C below the glass transition temperature (T g ) measured by DSC at 10°C min -1 heating rate (T g =218°C), and ageing times (t a ) between 0 and 8640min, were analysed. Calorimetric results show the presence of an endothermic peak, associated with the enthalpy recovery at the glass transition. This peak shifts towards higher temperatures and its height and area increase as the annealing time increases for a given T,. The maximum enthalpy relaxation is achieved at T a = T g - 18°C (T a = 200°C) for every annealing time, indicating that this is the optimum temperature to age this material. TSDC results show for each T a a shift of the α peak towards higher temperatures, and a considerable decrease in maximum current and area as t a increases. The activation energies (E a ), calculated from the TSDC curves for the α relaxation, are mainly independent of the annealing temperature and time. The pre-exponential factor for the relaxation time (τ 0 ), evaluated from the same curves, shows a slight decrease when the annealing time is increased at a given temperature.
