ABSTRACT
The construction of supramolecular aerogels still faces great challenges. Herein, we present a novel bio-based supramolecular aerogel derived from G-Quadruplex self-assembly of guanosine (G), boric acid (B) and sodium alginate (SA) and the obtained GBS aerogels exhibit superior flame-retardant and thermal insulating properties. The entire process involves environmentally friendly aqueous solvents and freeze-drying. Benefiting from the supramolecular self-assembly and interpenetrating dual network structures, GBS aerogels exhibit unique structures and sufficient self-supporting capabilities. The resulting GBS aerogels exhibit overall low densities (36.5-52.4 mg/cm3), and high porosities (>95 %). Moreover, GBS aerogels also illustrate excellent flame retardant and thermal insulating properties. With an oxygen index of 47.0-51.1 %, it can easily achieve a V-0 rating and low heat, smoke release during combustion. This work demonstrates the preparation of intrinsic flame-retardant aerogels derived from supramolecular self-assembly and dual cross-linking strategies, and is expected to provide an idea for the realization and application of novel supramolecular aerogel materials.
ABSTRACT
A method was purposed for simultaneous determination of ammonium thiocyanate and its isomeride thiourea by dual wavelength multiplication subtractive spectrophotometry. The approach was based on the measurement of the absorbance of both standard solutions and mixture samples at 216 and 236 nm. The concentration of ammonium thiocyanate and thiourea was obtained through the calculation of balancing coefficient and slope. The method was successfully applied to the determination of ammonium thiocyanate and thiourea, which existed in isomerization reaction. A comparison was also made with the dual wavelength method and reversed ion-pair chromamotography, and the dual wavelength multiplication subtractive spectrophotometry offered the advantages of simple, rapid and accurate determination.
