Starch-Based Aerogels Obtained via Solvent-Induced Gelation

Abstract

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-CO2) 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 m2 g−1) and low envelope densities (0.097–0.203 g cm−3). 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-CO2, avoiding the time-consuming step of solvent exchange.

Starch Alcogels, Aerogels, and Aerogel-like Xerogels: Adsorption and Release of Theophylline

“…It indicates that starches adsorb theophylline from ethanol. We suppose that this is due to a better affinity of theophylline to starch as compared to ethanol, as confirmed by the values of solubility parameters of theophylline 33 (23.53 MPa 1/2 ), starch 34 (24 MPa 1/2 ), and ethanol 35 (26.5 MPa 1/2 ). Experimental loading capacities of starch alcogels (eq 2) are presented in Figure 3a.…”

Properties of blends from pregelatinized starch with poly (vinyl alcohol) for hygienic-purposed disposable laundry bags

“…The HSP approach considers three major types of molecule interactions: dispersive interactions, dipole-dipole interactions, and hydrogen bonding, as discussed in previous reports. 23–25…”

“…The HSP approach considers three major types of molecule interactions: dispersive interactions, dipole-dipole interactions, and hydrogen bonding, as discussed in previous reports. [23][24][25] The solubility time of PVOH/pregelatinized starch blend films tended lower when glycerol molecules and pregelatinized starch were added to PVOH. The water solubility time of the blend with 10 wt% of pregelatinized starch (P-St 10) was lower than that of P-St 0 due to the presence of starch molecules, whereas the increase of pregelatinized starch content not only led to delay in the blend dissolving in water but also reduced the percent moisture content.…”

Tissue Adhesion-Anisotropic Polyrotaxane Hydrogels Bilayered with Collagen

“…On the contrary, the Me 322 PRX-VBn solution was clear, which suggests that it was completely dissolved in water. Heterogeneous dispersion of monomers and crosslinkers can reduce the mechanical strength of hydrogels [ 30 , 31 ]. Therefore, in the present study, PRX hydrogels were fabricated using Me 322 PRX-VBn.…”