Effect of physical aging on the gas transport properties of poly(methyl methacrylate) membranes

Hu, Chien‐Chieh; Fu, Ywu-Jang; Hsiao, Sheng-Wen; Lee, Kueir‐Rarn; Lai, Juin‐Yih

doi:10.1016/j.memsci.2007.06.004

Cited by 28 publications

(12 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Cabe señalar que este es un fenómeno espontáneo que ha sido ampliamente estudiado en polímeros sintéticos [10][11][12][13][14][15][16], pero que requiere de mayor investigación en el área de biomateriales debido a las implicancias tecnológicas que éste posee. Durante un proceso de relajación se observan cambios significativos en algunas propiedades físicas del material, como por ejemplo aumento del módulo elástico [17][18][19], aumento de fragilidad [20] y disminución en los valores de permeabilidad y difusividad [21][22][23][24]. Este comportamiento estaría gobernado por la modificación estructural asociada con una organización molecular más compacta y un incremento en el grado de interacción molecular producto del fenómeno de relajación [9].…”

Section: Palabras-chave: Gelatina Plastificantes Estado Vítreo Relunclassified

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Díaz-Calderón¹,

Quero²,

MacNaughtan³

et al. 2015

rev.ion

View full text Add to dashboard Cite

Resumen El objetivo de este trabajo fue evaluar el efecto del sorbitol sobre la cinética de relajación estructural de películas de gelatina almacenadas bajo la temperatura de transición vítrea (Tg). Películas de gelatina de bovino y sorbitol fueron preparadas mediante casting en frío. El sorbitol fue agregado en fracciones en peso (Qs) de 0,0, 0,06 y 0,10. Las películas fueron acondicionadas en un ambiente de humedad relativa constante (44%) utilizando una solución saturada de carbonato de potasio, obteniéndose fracciones de contenido de humedad en peso (Qw) de 0,18, 0,16 y 0,18 respectivamente. La entalpía de relajación (∆H) fue determinada mediante Calorimetría Diferencial de Barrido (DSC). Las muestras utilizadas en este estudio presentaron valores de Tg de 48ºC (Qs=0,0), 35ºC (Qs=0,06) y 30ºC (Qs=0,10). Luego de eliminar el historial térmico (30ºC sobre Tg, 15min), las muestras fueron almacenadas isotérmicamente a 10ºC bajo Tg onset entre 2 y 80 horas. La adición de sorbitol produjo una reducción signifi cativa (p<0,05) en la cinética de relajación estructural. La linealización del valor de entalpía de relajación (∆H) en función del logaritmo del tiempo de almacenamiento mostró una reducción de la pendiente en las muestras plastifi cadas con sorbitol. La reducción en la cinética de relajación estaría relacionada con el efecto de empaquetamiento molecular asociado a la presencia de polioles en matrices en estado vítreo recientemente reportada mediante espectroscopía de positrones (PALS).

show abstract

Section: Palabras-chave: Gelatina Plastificantes Estado Vítreo Relunclassified

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Díaz-Calderón¹,

Quero²,

MacNaughtan³

et al. 2015

rev.ion

View full text Add to dashboard Cite

show abstract

“…Consequently, gas permeability generally decreases and selectivity increases with aging [3][4][5]. Several studies have demonstrated the influence of physical aging on gas transport properties of thick films (> 1 µm) [6][7][8][9]. As film thickness decreases into the range (~ 0.1 µm [10][11][12]) relevant for commercial gas separation membranes, gas permeability decreases more rapidly, suggesting accelerated aging in thin films [3,13,14].…”

Section: Introductionmentioning

confidence: 99%

Effect of UV irradiation and physical aging on O2 and N2 transport properties of thin glassy poly(arylene ether ketone) copolymer films based on tetramethyl bisphenol A and 4,4′-difluorobenzophenone

Liu

Shaver

Chen

et al. 2016

Polymer

View full text Add to dashboard Cite

Modification of membranes to improve gas separation properties has been of considerable interest. Crosslinking is one route to modify membranes, but such studies need to be performed on thin membranes to quantify the impact of such modifications at thicknesses relevant to industrial membranes. In this study, the influences of UV irradiation and physical aging on O 2 and N 2 gas permeation properties of thin (~ 150 nm) glassy, amorphous poly(arylene ether ketone) (PAEK) copolymer films at 35 o C and 2 atm were investigated. Thin PAEK copolymer films, prepared from tetramethyl bisphenol A (TMBPA) and 4,4'-difluorobenzophenone (DFBP), were UV irradiated on both sides in air or N 2 at 254 nm or 365 nm, which induced crosslinking and, in some cases, photooxidation. Gas permeability decreased and O 2 /N 2 selectivity increased as UV irradiation and aging time increased. At 254 nm, samples irradiated in air have lower permeability coefficients and higher selectivities than samples irradiated in N 2 , which was ascribed to additional decreases in free volume due to photooxidation in samples irradiated in air. Additionally, samples irradiated in air at 254 nm exhibit less physical aging than uncrosslinked and samples irradiated in N 2 at 254 nm, possibly due to interactions among photooxidative polar products that may restrict polymer chain mobility, thereby lowering the aging rate. The influence of water vapor on physical aging of samples irradiated in air was examined. Finally, irradiation at 254 nm leads to more extensive crosslinking and/or photooxidation than irradiation at 365 nm, possibly due to greater UV absorption by the polymer and the higher probability of radical formation at the lower wavelength.

show abstract

“…the decrease in gas permeabilities, physical aging often causes also an increase of the separation efficiency of the polymer [35,36]. Indeed, the decrease of the void dimensions usually affects more significantly the penetrant with the lower permeability (or the one with larger kinetic diameter), thus enhancing membrane selectivity.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermal Treatment and Physical Aging on the Gas Transport Properties in Matrimid^®

Ansaloni

Minelli

Baschetti

et al. 2014

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

-Carbon dioxide and methane transport in a commercial polyimide, Matrimid 5218 Ò , has been characterized in order to evaluate the effect of membrane thermal treatment and physical aging on its potentialities for CO 2 /CH 4 separation. In particular, CO 2 and CH 4 permeabilities and diffusion coefficients were measured at three different temperatures (35, 45 and 55°C) in films pretreated at 50, 100, 150 and 200°C, respectively. The performances of each sample were examined for a period of more than 3 000 hours. Permeability and diffusivity values for both penetrants showed a marked decrease with increasing the pretreatment temperature up to 150°C and remained, then, substantially unchanged for specimens pretreated at the highest temperature. Interestingly, the samples characterized by the higher flux after film formation also showed a faster aging phenomenon, leading to a 25% decrease of CO 2 permeability in the period inspected. Conversely, the samples pretreated at temperatures of 150°C, or higher, displayed very stable transport properties for the entire duration of the monitoring campaign. At the end of the aging period considered, the differences among samples were definitely reduced, suggesting that the initial behaviors are related to different polymer structures induced by pretreatment, which slowly evolve in time towards more similar and more stable configurations. Such aging rearrangements affect both CO 2 and CH 4 permeability in a similar way, so that no significant changes were observed for selectivity, which showed only a slight increment by increasing the temperature of the thermal treatment or the duration of the aging period. 150°C ont affiche´des proprie´te´s de transport tre`s stables pendant toute la dure´e des mesures. Par conse´quent, a`la fin de l'e´tude, les diffe´rences entre les e´chantillons ont e´te´nettement re´duites, ce qui sugge`re que la structure initiale pourrait eˆtre due a`des structures polyme´riques diffe´rentes, induites par un pre´traitement, qui e´voluent lentement avec le temps vers des configurations plus semblables et plus stables. Il est important de remarquer qu'un tel re´arrangement a affected e la meˆme manie`re la perme´abilite´au CO 2 et celle au CH 4 . Nous n'observons donc pas de changements significatifs en ce qui concerne la se´lectivite´qui a montre´seulement une le´ge`re hausse lorsque l'on augmente la tempe´rature du traitement thermique ou le temps de vieillissement.

show abstract

Effect of physical aging on the gas transport properties of poly(methyl methacrylate) membranes

Cited by 28 publications

References 35 publications

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Effect of UV irradiation and physical aging on O2 and N2 transport properties of thin glassy poly(arylene ether ketone) copolymer films based on tetramethyl bisphenol A and 4,4′-difluorobenzophenone

Effects of Thermal Treatment and Physical Aging on the Gas Transport Properties in Matrimid^®

Contact Info

Product

Resources

About

Effect of physical aging on the gas transport properties of poly(methyl methacrylate) membranes

Cited by 28 publications

References 35 publications

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Efecto del sorbitol sobre la relajación estructural en películas de gelatina en estado vítreo

Effect of UV irradiation and physical aging on O2 and N2 transport properties of thin glassy poly(arylene ether ketone) copolymer films based on tetramethyl bisphenol A and 4,4′-difluorobenzophenone

Effects of Thermal Treatment and Physical Aging on the Gas Transport Properties in Matrimid®

Contact Info

Product

Resources

About

Effects of Thermal Treatment and Physical Aging on the Gas Transport Properties in Matrimid^®