Physical transitions in polymers plasticized by interacting penetrant

Semenova, Svetlana I.; Ohya, Haruhiko; Smirnov, S. I.

doi:10.1016/s0376-7388(97)00148-8

Cited by 20 publications

(9 citation statements)

References 11 publications

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“…For example, it is reported that poly(ethylene terephthalate) shows this drift of sorption curve at high water vapor activity (above a w = 0.6), even at low temperature [ 10 , 21 ]. Several authors associated these relaxations in glassy polymers to morphological changes, such as plasticization [ 26 , 27 ] and free volume increase [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

Water Vapor Sorption and Diffusivity in Bio-Based Poly(ethylene vanillate)—PEV

et al. 2021

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The dynamic and equilibrium water vapor sorption properties of amorphous and highly crystalline poly(ethylene vanillate) (PEV) films were determined via gravimetric analysis, at 20 °C, over a wide range of relative humidity (0–95% RH). At low RH%, the dynamic of the sorption process obeys Fick’s law while at higher relative humidity it is characterized by a drift ascribable to non-Fickian relaxations. The non-Fickian relaxations, which are responsible for the incorporation of additional water, are correlated with the upturn of the sorption isotherms and simultaneously the hysteresis recorded between sorption and desorption cycles. The sorption isotherms of amorphous and highly crystalline PEV are arranged in the same concentration range of that of PET proving the similarity of the two polyesters. Water diffusion coefficients, whose determination from individual kinetic sorption/desorption curves required treatment with the Barens–Hopfenberg model, were demonstrated to be ≈ 10× higher for amorphous PEV compared to amorphous PET. Such a difference originates from the enhanced segmental flexibility of PEV chains.

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Section: Resultsmentioning

confidence: 99%

Water Vapor Sorption and Diffusivity in Bio-Based Poly(ethylene vanillate)—PEV

et al. 2021

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“…where V m is the molar volume of water vapor (22414 cm 3 •mol −1 ), M w the water molecular weight (18 g•mol −1 ), and V p the polymer volume (cm 3 ). Complete sorption was collected at five temperatures: 23, 40, 50, 60, and 70 °C (Figure 1).…”

Section: Methodsmentioning

confidence: 99%

Water Vapor Sorption Properties of Polyethylene Terephthalate over a Wide Range of Humidity and Temperature

et al. 2017

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The dynamic and equilibrium water vapor sorption properties of amorphous polyethylene terephthalate were determined via gravimetric analysis over a wide range of temperatures (23-70 °C) and humidities (0-90% RH). At low temperature and relative humidity, the dynamics of the sorption process was Fickian. Increasing the temperature or relative humidity induced a distinct up-swing effect, which was associated with a plasticization/clustering phenomenon. For high temperatures and relative humidity, a densification of the polymer was evidenced. In addition to the classical Fickian diffusion, a new parameter was introduced to express the structural modifications of PET. Finally, two partial pressures were defined as thresholds that control the transition between these three phases. A simplified state diagram was finally proposed. In addition, the thermal dependence of these sorption modes was also determined and reported. The enthalpy of Henry's water sorption and the activation energy of diffusion were independent of vapor pressure and followed an Arrhenius law.

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“…It is known that the sorption of penetrant molecules in a glassy polymer can induce strong plasticization effects. [13][14][15][16] Next to Fickian diffusion on a short time scale, long time scale relaxations can be observed. 16 Equilibrium is not reached due to the glassy state of the polymer.…”

Section: Introductionmentioning

confidence: 99%

Sorption induced relaxations during water diffusion in S-PEEK

Potreck

Uyar

Sijbesma

et al. 2009

Phys. Chem. Chem. Phys.

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This paper presents an analysis of the sorption kinetics of water vapor and liquid water in the glassy polymer sulfonated poly(ether ether ketone) (S-PEEK). Sorption isotherms are determined experimentally using a gravimetric sorption balance, and the relative contributions of Fickian diffusion and relaxational phenomena are quantified as a function of the water concentration in the polymer using the model of Hopfenberg and Berens.Analysis of the sorption isotherms and determination of the sorption kinetics prove the occurrence of both Fickian sorption behavior and relaxational phenomena already at very low water concentrations in the polymer. With increasing water concentration, the relative importance of relaxation phenomena increases, whereas the relative contribution of Fickian diffusion decreases.Based on the water vapor sorption kinetics only, the Fickian diffusion coefficient increases over two orders of magnitude with increasing water vapor concentration. Taking also the diffusion kinetics from liquid water sorption experiments into account reveals a change of even three orders of magnitude of the Fickian diffusion coefficient when the water concentration in the polymer increases.

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Physical transitions in polymers plasticized by interacting penetrant

Cited by 20 publications

References 11 publications

Water Vapor Sorption and Diffusivity in Bio-Based Poly(ethylene vanillate)—PEV

Water Vapor Sorption and Diffusivity in Bio-Based Poly(ethylene vanillate)—PEV

Water Vapor Sorption Properties of Polyethylene Terephthalate over a Wide Range of Humidity and Temperature

Sorption induced relaxations during water diffusion in S-PEEK

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