A Novel Ultra-High Swelling Organogel: An Epoxy Resin Derived Gelator for Alcohols and Polar Organic Liquids

Hypothesis: Organogels are hydrophobic macromolecular networks with ability to absorb and retain organic solvents. They have been used in various applications, e.g., production of disinfectant hygienic gels used in medicine and public health. The present paper is a preliminary report on the conversion of common epoxy resin (DGEBA) into a new superabsorbent organogel containing functional groups of furan, carbamate, and triazole.Methods: The organogel was synthesized through a four-step strategy from epoxy resin and furfuryl alcohol. The furfurylated epoxy resin was converted to an isocyanate-terminated compound that then converted into a propargyl-terminated intermediate. The final product was produced by 1,3-dipolar cycloaddition polymerization reaction of a propargylated compound and a diazide compound prepared from epichlorohydrin. The intermediate compounds and the final product were characterized by Fourier transform infrared (FTIR) spectroscopy. The final product was characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Rheological behavior in solvent N-methyl-2-pyrrolidone (NMP) was preliminarily studied and swelling capacity of the organogel was determined in various solvents.Findings: A novel polymeric organogel was synthesized without using a particular crosslinker. Its dried particles were found to have porosity with a pore diameter of ~680 nm. The organogel showed increased swelling capacity with dropping of solvent viscosity and increasing of solvent polarity. The high solvent uptake and storage capacity by this organogel has supported it as a superabsorbent organogelator. Its swelling capacity was determined in the solvents to be in order: ethylene glycol < chloroform < ethanol < acetonitrile < dimethylformamide < dimethylacetamide < dimethylsulfoxide < NMP. For instance, each gram of the organogel can absorb and gelate ~145 g ethanol, or ~1853 g NMP, within ~1 h. The super-swelling behavior of this solvent-retaining network was preliminarily attributed to a combination of limited crosslinkages as well as some polymer-polymer and polymer-solvent supramolecular interactions. The presence of 1,2,3-triazole groups is also expected to induce antibacterial properties in this organogel.