Hybrid alginate based aerogels by carbon dioxide induced gelation: Novel technique for multiple applications
Hybrid alginate based aerogels by carbon dioxide induced gelation: Novel technique for multiple applications
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DOI：
10.1016/j.supflu.2015.05.003
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发表时间：
2015-11-01
影响因子：
3.9
通讯作者：
Smirnova, Irina
中科院分区：
文献类型：
--
作者：
Raman, S. P.;Gurikov, Pavel;Smirnova, Irina
本文介绍了一种制备海藻酸盐基杂化气凝胶的技术。该技术涉及在海藻酸钠溶液中混合第二组分（生物聚合物或填充材料），并与金属如钙、锶、钴、镍、锌和铜的碳酸盐交联。使用各种生物聚合物（木质素、淀粉、果胶、角叉菜胶、甲基和羧甲基纤维素、结冷胶和明胶）、聚合物（PVA、PEG、Pluronic P-123）、无机物（硅酸钠）和填充材料（二氧化钛和疏水二氧化硅）作为第二组分。建议使用加压二氧化碳（5 MPa）进行凝胶化和超临界CO2干燥（10-12 MPa）以产生气凝胶。所获得的气凝胶是超多孔的，具有低密度（低至0.017 g/cm（3））、高比表面积（200-800 m2/g）和孔体积（对于孔径< 150 nm，为2.3-9.5 cm（3）/g）。展示了表达这些气凝胶的适用性的基本实施例，例如在热绝缘领域（热导率在18.5- 21.6mW/m K的范围内）。还证明了二氧化碳凝胶化技术从金属交联藻酸盐基系统扩展到其他生物聚合物（纤维素和壳聚糖）。(C)2015 Elsevier B. V.版权所有。
This paper presents a technique of manufacturing alginate-based hybrid aerogels. The technique involves mixing a second component (biopolymers or filler materials) in sodium alginate solution and crosslinking with carbonates of metals like calcium, strontium, cobalt, nickel, zinc and copper. Various biopolymers (lignin, starch, pectin, carrageenan, methyl and carboxymethyl cellulose, gellan gum, and gelatin), polymers (PVA, PEG, Pluronic P-123), inorganic (sodium silicate) and filler materials (titania and hydrophobic silica) were used as the second component. It is suggested to use pressurized carbon dioxide (5 MPa) for gelation and supercritical CO2 drying (10-12 MPa) to yield aerogels. Obtained aerogels are ultraporous with low density (as low as 0.017 g/cm(3)), high specific surface area (200-800 m(2)/g) and pore volume (2.3-9.5 cm(3)/g for pore sizes < 150 nm). Basic examples expressing the applicability of these aerogels are demonstrated such as in the field of thermal insulation (thermal conductivity in the range 18.5-21.6 mW/m K). Extension of carbon dioxide gelation technique from metal-crosslinked alginate-based system to other biopolymers (cellulose and chitosan) is also demonstrated. (C) 2015 Elsevier B.V. All rights reserved.