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Conducting Polymer-Based Nanomaterials for Tissue Engineering
Published in Ram K. Gupta, Conducting Polymers, 2022
Murugan Prasathkumar, Chenthamara Dhrisya, Salim Anisha, Robert Becky, Subramaniam Sadhasivam
Aerogels are porous materials with attractive properties such as high specific surface area, low thermal conductivity, high pore volume, and high porosity. Their potential biomedical applications include wound care, drug delivery system, tissue engineering. Alginate, cellulose, gellan gum, and DNA have been widely used as a template for in situ polymerization with CPs. The nanoporous cellulose gels–PPy composite aerogel can provide sufficient electrical conductivity and no cytotoxic effects against nerve cells [11]. PANI aerogels are notable conductive polymeric biomaterials that have been received good attention due to their low cost, tunable morphology, redox properties, and environmental stability, but lack of strong chemical or physical interactions. The PANI cross-linked with pectin aerogel has exhibited considerable electrical conductivity, hierarchical pores, high mechanical integrity, and self-supported 3D nanoporous network structures with high surface areas [12].
Foam in Insulation
Published in S. T. Lee, Polymeric Foams, 2022
Xiangmin Han, Barbara Fabian, Bruce Kline, Chase Boudreaux, Nigel Ravenscroft
Application of aerogels to insulation is a second approach [36–41]. To demonstrate the impact from nano-sized pores, silica aerogel, Cabot P200, was gently mixed with polystyrene powders at different weight ratios, and then hot compressed into a thin disk for thermal conductivity measurement. Depending on the amount of aerogel used, its volume percentage varied from 55% to 95%, where PS works as a hot glue for aerogel powders. The thermal conductivity of these PS/aerogel composites is plotted against the volume percentage of aerogel in Figure 7.10. The thermal conductivity decreases linearly with the volume percentage of aerogel and it is possible to make an R 5/in (29 mW/m.K) sample at about 87% aerogel by volume. However, at this high aerogel usage level, the sample becomes weak and brittle and expensive.
Carbon Nanomaterials and Biopolymers Derived Aerogels for Wastewater Remediation
Published in Uma Shanker, Manviri Rani, Liquid and Crystal Nanomaterials for Water Pollutants Remediation, 2022
Kanika Gupta, Pratiksha Joshi, Om P Khatri
The carbon aerogels having 3D interconnected structural building blocks, exhibit outstanding physical properties and promises their potential in energy storage, electromechanical sensing, biomedical, oil-water separation, electrocatalysis, wastewater treatment, and chemical adsorption (T. Chen et al. 2020, Lee and Park 2020, C. Wang et al. 2020). Carbon aerogels are primarily composed of graphene, carbon nanotubes, carbon nanofibers, biomass-derived carbon, polymeric carbon, carbide, and carbonitride-based precursors (T. Chen et al. 2020, Lee and Park 2020). The properties of carbon aerogels are governed by preparation conditions, type of carbon materials, and binders. The microporous structure of aerogels is governed by the intraparticle/building block framework, whereas the interparticle structure furnishes meso- and macroporosity (Lee and Park 2020). The conventional route for carbon aerogels synthesis involves sol-gel/hydro-gel chemistry by transforming molecular precursors into cross-linked organic gels. Subsequently, the carbonization in an inert atmosphere generates carbon aerogels. Graphene and carbon nanotubes are the emerging precursors for carbon aerogels, and their individual properties are translated into 3D free-standing macroscopic assemblies. However, the preparation cost and tedious process of these aerogels impede their use in many areas, mainly for energy and environmental applications. Therefore, efficient and economical routes to fabricate carbon aerogels based on renewable resources are gaining increasing interest (S. C. Li et al. 2018).
Synthesis of cellulosic and nano-cellulosic aerogel from lignocellulosic materials for diverse sustainable applications: a review
Published in Preparative Biochemistry & Biotechnology, 2023
Anisha Ganguly, Soma Nag, Kalyan Gayen
Aerogels are solid materials with a large number of micro/nano level pores resulting in a high internal surface area (∼5–500 m2/g), high porosity (∼81–99.9%), and low density (0.02 g/cm3–0.2g/cm3). Furthermore, it has high rigidity, and low thermal conductivity, and can bear weight much more times than its weight.[20,21] Historically, in 1930, first time, SS Kistler obtained an aerogel from silica by evaporating the liquid using supercritical drying from wet gel.[22] Silica was the most common raw material for aerogel preparation.[23] However, aerogels can also be obtained using various other inorganic compounds like vanadium pentaoxide (V2O5), titanium dioxide (TiO2), borate-based, silica and alumina.[24–27] Limitations of this type of aerogel are high production cost, high delicacy, and a tendency to break while a small load is applied.[21] These limitations have confined their uses and there was a need to develop a sustainable and biodegradable aerogel with high delicacy, more brittle and high mechanical strength.
A comprehensive state-of-the-art review of sustainable thermal insulation system used in external walls for reduction in energy consumption in buildings
Published in International Journal of Green Energy, 2023
K. S. Dhaya Chandhran, S. Elavenil
To form the aerogel, under special drying conditions the liquid is removed from the gel, neglecting and avoiding the cracking and shrinkage in the ambient evaporation method, aerogels are formed. It contains 80–99% of air in a three dimensional nano porous structure (Bozic 2015). Solar and light radiation passes through the high porosity of aerogels as they are transparent, also having a lower thermal conductivity than any other solids. All the above mentioned properties make the Aerogel as an ideal insulating material for thermal insulation with a low thermal conductivity (13 mW/mK). Gao et al. (2014) achieved a thermal conductivity of 0.037 W/mK in cellulose fibrous mat with freeze dried bacteria embedded with silica based sol (Buratti and Moretti 2012; Błaszczynski, Slosarczyk, and Morawski 2013; Carty 2017; Cuce et al. 2014; Fujimoto 2009; Higueras and Omar 2016; Illera et al. 2018; Omar and Sabsaby 2015a; Pedroso et al. 2020). Figure 7 depicts the usage of silica aerogel composite glazing panels.
Experimental study of using Aerogel insulation for residential buildings
Published in Advances in Building Energy Research, 2022
Mohamed T. Elshazli, Mohammad Mudaqiq, Tao Xing, Ahmed Ibrahim, Brian Johnson, Jinchao Yuan
Aerogel insulation is a most propitious insulation solution, and it was first discovered in 1931 (Abu-Jdayil et al., 2019; Fricke & Tillotson, 1997; Mahadik et al., 2016). It is a dried gel with high porosity and has lower thermal conductivity than air (Abu-Jdayil et al., 2019; Baetens et al., 2011; Jelle, 2011). Aerogels are made by removing liquids from gels, ending up in a material that is more than 90% air. This porous composition of that nanomaterial makes it difficult for the heat to transfer through its structure. As a result, a good, efficient and light-weight insulation is produced (Berardi, 2019). Aerogel is synthetic transparent, highly porous, ultra-light, low density (bulk density 3–20.0 kg/m3), and has a large internal surface area. Moreover, having a unique microstructure (1–20 nm particle diameter and 2–50 nm pore diameter) and a great porosity (can reach up to 90%) result in more desired properties, such as the lowest thermal conductivity, refractive index, sound velocity and dielectric constant of any solid ever tested (Abu-Jdayil et al., 2019; Baetens et al., 2011). Aerogel has thermal conductivity ranging from 10 to 20 mW/(m.K) at ambient pressure. Aerogels have a relatively high compressive strength, and a very low tensile strength which make them a fragile brittle material (Abu-Jdayil et al., 2019; Baetens et al., 2011). The tensile strength could be increased by the incorporation of a carbon fibre matrix.