Gas Permeability Through Thermosets

Sandhya, P.K.; Ravindran, Lakshmipriya; Sreekala, M. S.

doi:10.1016/b978-0-12-809884-4.00023-9

Cited by 3 publications

(4 citation statements)

References 64 publications

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“…The free volume fluctuates slightly due to molecular movement and oscillations, and it is affected by the molecule structure and intermolecular forces. If the molecular cohesion is high, the molecules become more tightly packed, and the free volume decreases . For penetrant diffusion, the effective free volume depends on the size of the penetrant molecules.…”

Section: Methodsmentioning

confidence: 99%

“…If the molecular cohesion is high, the molecules become more tightly packed, and the free volume decreases. 18 For penetrant diffusion, the effective free volume depends on the size of the penetrant molecules. The fractional free volume (FFV) is defined as: where V occupied is the volume occupied by the van der Waals volume of the atoms and V total is the total volume in the system.…”

Section: Methodsmentioning

confidence: 99%

Section: Molecular Dynamics Simulations 211 Systemmentioning

confidence: 99%

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Molecular Dynamics Simulations of Cellulose and Dialcohol Cellulose under Dry and Moist Conditions

Elf,

Özeren,

Larsson

et al. 2023

Biomacromolecules

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The development of wood-based thermoplastic polymers that can replace synthetic plastics is of high environmental importance, and previous studies have indicated that cellulose-rich fiber containing dialcohol cellulose (ring-opened cellulose) is a very promising candidate material. In this study, molecular dynamics simulations, complemented with experiments, were used to investigate how and why the degree of ring opening influences the properties of dialcohol cellulose, and how temperature and presence of water affect the material properties. Mechanical tensile properties, diffusion/ mobility-related properties, densities, glass-transition temperatures, potential energies, hydrogen bonds, and free volumes were simulated for amorphous cellulosic materials with 0−100% ring opening, at ambient and high (150 °C) temperatures, with and without water. The simulations showed that the impact of ring openings, with respect to providing molecular mobility, was higher at high temperatures. This was also observed experimentally. Hence, the ring opening had the strongest beneficial effect on "processability" (reduced stiffness and strength) above the glass-transition temperature and in wet conditions. It also had the effect of lowering the glass-transition temperature. The results here showed that molecular dynamics is a valuable tool in the development of wood-based materials with optimal thermoplastic properties.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Molecular Dynamics Simulations of Cellulose and Dialcohol Cellulose under Dry and Moist Conditions

Elf,

Özeren,

Larsson

et al. 2023

Biomacromolecules

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“…A similar general increase in permeability for increasing free volume fractions seems to be reasonable. Sandhya et al confirm that, when the gases diffuse through polymeric membranes with low free volume fractions, they cannot penetrate efficiently into the system, thereby decreasing the permeability of the gas [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

Gas Permeability through Polyimides: Unraveling the Influence of Free Volume, Intersegmental Distance and Glass Transition Temperature

Torres,

Soto,

Carmona

et al. 2023

Polymers

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The relationships between gas permeability and free volume fraction, intersegmental distance, and glass transition temperature, are investigated. They are analyzed for He, CO2, O2, CH4, and N2 gases and for five similar polyimides with a wide range of permeabilities, from very low to extremely high ones. It has been established here that there is an exponential relationship between permeability and the free volume fraction, and between permeability and the most probable intersegmental distance as measured by WAXS; in both cases, with an exponential coefficient that depends on the kinetic gas diameter as a quadratic polynomial and with a preexponential positive constant. Moreover, it has been proven that the intersegmental distance increases linearly with the free volume fraction. Finally, it has been established that the free volume fraction increases with the glass transition temperature for the polymers tested, and that they depend on each other in an approximate linear way.

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Influence of semi-crystalline microstructure on gas permeability of Poly(Ether-Ketone-Ketone)

Durand,

De Almeida

2024

Polymer

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Gas Permeability Through Thermosets

Cited by 3 publications

References 64 publications

Molecular Dynamics Simulations of Cellulose and Dialcohol Cellulose under Dry and Moist Conditions

Molecular Dynamics Simulations of Cellulose and Dialcohol Cellulose under Dry and Moist Conditions

Gas Permeability through Polyimides: Unraveling the Influence of Free Volume, Intersegmental Distance and Glass Transition Temperature

Influence of semi-crystalline microstructure on gas permeability of Poly(Ether-Ketone-Ketone)

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