Characterization of hyperporous polyurethane-based gels by non-intrusive mercury porosimetry

Pirard, René; Rigacci, Arnaud; Marechal, Jacqueline; Quénard, Daniel; Chevalier, Bruno; Achard, Patrick; Pirard, Jean-Paul

doi:10.1016/s0032-3861(03)00481-6

Cited by 55 publications

(32 citation statements)

References 14 publications

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“…The large hysteresis can be attributed to the fact that, when depressurization of the cell is realised, almost no mercury comes out of the sample, confirming its irreversible compression [42]. This peculiar behaviour of RF xerogels has been reported recently [32].…”

Section: Mechanical Propertiessupporting

confidence: 71%

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Léonard

Blacher

Crine

et al. 2008

Journal of Non-Crystalline Solids

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Porous carbon xerogels can be obtained by convective drying of resorcinol (R)-formaldehyde (F) hydrogels, followed by pyrolysis. Drying conditions have to be carefully controlled when crack-free monoliths with well-defined shape and size are required. The knowledge of the mechanical properties of the RF xerogels and their evolution with water content is essential to model their thermo-hygro-mechanical behaviour during convective drying and avoid mechanical stresses leading to deformation and cracking of the sample. The shrinkage behaviour and the mechanical properties of RF xerogels obtained with R/C ratio ranging from 300 to 1500 were investigated. R/C greatly influences the shrinkage and mechanical properties of the wet gel, on the one hand, and the mechanical and textural properties of the dried gel, on the other hand. The smaller the R/C, the higher the shrinkage, the stiffening, and the viscoelastic character of the xerogels. Water content has an influence on both the stiffness of the gels and the viscoelastic response. Generally, samples lose their mechanical viscous character and become more rigid when they are dried. Finally, mercury porosimetry measurements showed that the gels exhibit a marked lowering of 2 their stiffness upon compression, interpreted as a result of the heterogeneity of the microstructure.

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Section: Mechanical Propertiessupporting

confidence: 71%

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Léonard

Blacher

Crine

et al. 2008

Journal of Non-Crystalline Solids

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“…where k is a constant depending on pore wall thickness and Young modulus and is to be determined in separate experiments from porous volume evolution during isostatic compression (Pirard et al, 2003). The constant k had never been determined for aerocelluloses and this task was not in the scope of our work.…”

Section: Aerocellulose Morphology Density and Pore Size Distributionmentioning

confidence: 99%

Aerocellulose from cellulose–ionic liquid solutions: Preparation, properties and comparison with cellulose–NaOH and cellulose–NMMO routes

Sescousse¹,

Gavillon²,

Budtova³

2011

Carbohydrate Polymers

249

174

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“…8a). Pore size distribution was thus calculated using buckling theory developed by Pirard et al 1995 for hyperporous materials and tested for polyurethane foams by Pirard et al 2003 and cellulose acetate aerogels by Fischer et al 2006. The result is shown in Fig.…”

Section: Semi-dilute Solutionsmentioning

confidence: 99%

Influence of lignin on cellulose-NaOH-water mixtures properties and on Aerocellulose morphology

2010

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International audienceMicrocrystalline cellulose and organosolv lignin, both dissolved in 8%NaOH-water, were mixed with the objective to study the influence of lignin on the properties of cellulose solutions and on the morphology of dry porous materials. Mixture viscosity and gelation were investigated. Cellulose-lignin gels were regenerated in aqueous acid baths and dried under supercritical CO2 to obtain Aerocellulose, an aerogel-like material. The presence of lignin in the mixture speeded up gelation. During regeneration part of lignin was washed out. This created large pores and channels in the dry materials. The overall results obtained showed that cellulose and lignin are not compatible in the solvent used

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Characterization of hyperporous polyurethane-based gels by non-intrusive mercury porosimetry

Cited by 55 publications

References 14 publications

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Evolution of mechanical properties and final textural properties of resorcinol–formaldehyde xerogels during ambient air drying

Aerocellulose from cellulose–ionic liquid solutions: Preparation, properties and comparison with cellulose–NaOH and cellulose–NMMO routes

Influence of lignin on cellulose-NaOH-water mixtures properties and on Aerocellulose morphology

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