Stress intensity factor in silica alcogels and aerogels

Alaoui, Adil Hafidi; Woignier, Thierry; Pernot, F.; Phalippou, J.; Hihi, A.

doi:10.1016/s0022-3093(99)00887-x

Cited by 14 publications

(4 citation statements)

References 17 publications

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“…It is well accepted that silica and cellulosic aerogels are “fragile materials” because of their poor mechanical properties, caused by the network’s limited connectivity and large porosity. The existence of defects, which act as stress concentrators, has a significant impact on rupture resistance [ 143 , 144 , 145 , 146 , 147 , 148 ]. Dog-bone-shaped specimens (as per ASTM D638 [ 149 ]) are often used for tension testing.…”

Section: Characterization Methods Of Cellulose-based Aerogelsmentioning

confidence: 99%

Incorporation of Cellulose-Based Aerogels into Textile Structures

Sozcu,

Venkataraman,

Wiener

et al. 2023

Materials

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Given their exceptional attributes, aerogels are viewed as a material with immense potential. Being a natural polymer, cellulose offers the advantage of being both replenishable and capable of breaking down naturally. Cellulose-derived aerogels encompass the replenish ability, biocompatible nature, and ability to degrade naturally inherent in cellulose, along with additional benefits like minimal weight, extensive porosity, and expansive specific surface area. Even with increasing appreciation and acceptance, the undiscovered possibilities of aerogels within the textiles sphere continue to be predominantly uninvestigated. In this context, we outline the latest advancements in the study of cellulose aerogels’ formulation and their diverse impacts on textile formations. Drawing from the latest studies, we reviewed the materials used for the creation of various kinds of cellulose-focused aerogels and their properties, analytical techniques, and multiple functionalities in relation to textiles. This comprehensive analysis extensively covers the diverse strategies employed to enhance the multifunctionality of cellulose-based aerogels in the textiles industry. Additionally, we focused on the global market size of bio-derivative aerogels, companies in the industry producing goods, and prospects moving forward.

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Section: Characterization Methods Of Cellulose-based Aerogelsmentioning

confidence: 99%

Incorporation of Cellulose-Based Aerogels into Textile Structures

Sozcu,

Venkataraman,

Wiener

et al. 2023

Materials

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“…Pores could be considered as flaws or as integral parts of flaw responsible for the failure of this brittle material. If such an assumption is valid, the critical flaw size should depend on the porosity and pore size (Hafidi-Alaoui et al 2000). Then, we have measured the toughness for alcogels and aerogels with different porosities in order to analyze the toughness evolution during the alcogel-aerogel transformation.…”

Section: Toughness and Critical Flaw Sizementioning

confidence: 99%

Evolution of the Mechanical Properties During the Gel–Glass Process

Woignier

Despetis

Etienne

et al. 2018

Handbook of Sol-Gel Science and Technology

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Different kinds of structure in alcogels and aerogels (fractal or not fractal) can be synthesized by a control of the chemical parameters and also by different steps in the preparation such as sintering and plastic compaction. The porosity of the gels is affected either by the adjustment of the gelifying concentration, by a precise control of the viscous flow sintering process, or by an isostatic pressure deformation. The different kinds of gels cover the whole range of porosity between 99% and 0%, and their mechanical properties (elastic modulus, strength, toughness) are strongly dependent on the porosity but also on their structure. We follow the mechanical properties of the over the whole process alcogelaerogelglass. They vary by five orders of magnitude as a function of the density, and for the same relative density, the elastic modulus and strength can increase by one order of magnitude due to a change in connectivity. The influence of the sintering process compared to isostatic pressure on the mechanical properties is explained by the associated structural changes.

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“…We will study the influence of synthesis parameters such as the concentration of gelifying precursors, pH of the hydrolysis solution and aging, on the physicochemical transformations observed during the supercritical fluid extraction. In the literature, mechanical testing has been made either on alcogels (West et al 1988;Zarzycki 1988;Scherer et al 1988) or on aerogels (Calemczuck et al 1987;Dumas et al 1990;Woignier et al 1988b;Gross and Fricke 1992;Woignier et al 2009), and comparison of the two sets of data suggests that supercritical drying enhances the mechanical features of the samples (Hafidi-Alaoui et al 2000). The application of linear elastic fracture mechanics to wet gels is questionable, because it is necessary to justify that the material has an elastic behavior and can be treated as a continuum.…”

Section: Mechanical Behavior Of Alcogels and Aerogels Elastic Moduli mentioning

confidence: 99%

“…The mechanical behavior of gels, xerogels and aerogels, is generally described in terms of brittle and elastic materials, like glass or ceramics (West et al 1988;Zarzycki 1988;Woignier and Phalippou 1988a;Hafidi-Alaoui et al 2000;Despetis et al 2004;Woignier et al 2015). During mechanical testing even for very porous material (99 %), the stress-strain curve shows a perfect elastic behavior and the conchoidal fracture morphology indicates that the material is brittle, like a conventional glass.…”

Section: Introductionmentioning

confidence: 99%