Cross-linked Nanoporous Saccharide-based Material and Methods for Fabrication Thereof

A thermally insulating and absorbing nanosponge for gas or liquid, comprising a cross-linked nanoporous saccharide-based material having monosaccharide units represented by chemical formula (I):

• wherein R1, R2, R3 is independently selected from hydrogen, methyl, ethyl, butyl, pentyl, octyl, acetyl, propionate, butyrate, benzoyl, phthalate, 2-hydroxyethyl, 2-hydroxypropyl, carboxymethyl, carboxymethyl sodium, 2-carboxyethyl sodium, sulfated sodium, t-butyldimethylsilyl, or cyanoethyl group;
• n is an integer from 6 to 1300;
• and
• wherein the saccharide-based material has an average pore radius in a range of 0.5 to 200 nm, a particle size in a range of 5 to 500 microns, a bulk density in a range of 1 to 680 kg/m3, and a thermal conductivity from 0.015 to 0.05 W/mK;
• wherein the saccharide-based material is obtained by reacting said monosaccharide units with one or more cross-linkers of the same kind or different kind at a mole ratio of anhydroglucose units of the monosaccharide units to cross-linkers in a range of 1:0.57 to 1:1 in a one-pot solvent system, followed by drying of the saccharide-based material, wherein the one or more cross-linkers each comprises two or more homofunctional or heterofunctional groups selected from carboxylic acid groups, or amine groups;
• wherein one or more additional functional groups are further introduced to the saccharides by further reacting the saccharides with one or more surface grafting agents at a mole ratio of an anhydroglucose unit of the saccharide to surface grafting agent in a range of 1:1 to 1:3 during said reaction, prior to and/or after said drying;
• wherein the one or more additional functional groups introduced by the surface grafting agents comprise epoxy, carboxylic acid, carboxylate, sulfo, sulfhydryl, amine, imine, isocyanate, nitrile, silyl or C3 to C21 hydrocarbon groups, or combinations thereof;
• wherein the monosaccharide units are linked to each other by alpha-glycosidic bonds or beta-glycosidic bonds;
• and
• wherein the thermally insulating and absorbing nanosponge exhibits one or more of a water retention capability from 1 to 520% with respect to the weight thereof, a water-repellent capability with a water contact angle at 140°, a capability of absorbing ammonia in a range of 1 to 600 mg/m3 per 1 g of the material, or capabilities of exchanging and absorbing metal ions including Cd, Cr, Pb, Cu, Zn, Co, Hg and/or Ni in a range of 0.1 to 1000 cmol of singly charged cation per kg of said material.