Dogenski Mirelle, Gurikov Pavel, Baudron Victor, Oliveira J Vladimir de, Smirnova Irina, Ferreira Sandra R S
Department of Chemical and Food Engineering, Federal University of Santa Catarina, Florianópolis 88040-900, Brazil.
Laboratory for Development and Modelling of Novel Nanoporous Materials, Hamburg University of Technology, Eißendorfer Straße 38, 21073 Hamburg, Germany.
Gels. 2020 Sep 19;6(3):32. doi: 10.3390/gels6030032.
In this work, the ability of several solvents to induce gel formation from amylomaize starch solubilized in dimethyl sulfoxide (DMSO) was investigated. The formed gels were subjected to solvent exchange using ethanol and dried with supercritical carbon dioxide (sc-CO) to obtain the aerogels. The influence of starch concentration (3-15 wt%) and solvent content (20-80 wt%) on gel formation was also studied. It was demonstrated that the gelation of starch in binary mixtures of solvents can be rationalized by Hansen Solubility Parameters (HSP) revealing a crucial hole of hydrogen bonding for the gel's strength, which is in agreement with rheological measurements. Only the addition of water or propylene glycol to starch/DMSO solutions resulted in strong gels at a minimum starch and solvent content of 7.5 wt% and 50 wt%, respectively. The resulting aerogels showed comparably high specific surface areas (78-144 m g) and low envelope densities (0.097-0.203 g cm). The results of this work indicate that the HSP parameters could be used as a tool to guide the rational selection of water-free gelation in starch/DMSO systems. In addition, it opens up an attractive opportunity to perform starch gelation in those solvents that are miscible with sc-CO, avoiding the time-consuming step of solvent exchange.
在这项工作中，研究了几种溶剂从溶解于二甲基亚砜（DMSO）中的直链玉米淀粉诱导凝胶形成的能力。将形成的凝胶用乙醇进行溶剂交换，并用超临界二氧化碳（sc-CO₂）干燥以获得气凝胶。还研究了淀粉浓度（3 - 15 wt%）和溶剂含量（20 - 80 wt%）对凝胶形成的影响。结果表明，通过汉森溶解度参数（HSP）可以合理地解释淀粉在二元溶剂混合物中的凝胶化过程，该参数揭示了氢键对凝胶强度的关键作用，这与流变学测量结果一致。只有向淀粉/DMSO溶液中添加水或丙二醇，分别在最低淀粉含量7.5 wt%和溶剂含量50 wt%时才能形成强凝胶。所得气凝胶具有相当高的比表面积（78 - 144 m²/g）和低堆积密度（0.097 - 0.203 g/cm³）。这项工作的结果表明，HSP参数可作为指导淀粉/DMSO体系中无水凝胶化合理选择的工具。此外，它为在与sc-CO₂互溶的溶剂中进行淀粉凝胶化开辟了一个有吸引力的机会，避免了耗时的溶剂交换步骤。
