Disclosed are cellulose-based 5 flexible aerogels and xerogels containing bacterial cellulose nanorods, ribbons, fibers, and the like, wherein the gels have tunable optical, heat transfer, and stiffness properties. Further disclosed are highly transparent and flexible cellulose nanofiber-polysiloxane composite aerogels featuring enhanced mechanical robustness, tunable optical anisotropy, and low thermal conductivity.

The present invention relates to a process for preparing a porous material, at least comprising the steps of providing a mixture (I) comprising a water soluble polysaccharide, at least one compound suitable to react as cross-linker for the polysaccharide or to release a cross-linker for the polysaccharide, and water, and preparing a gel (A) comprising exposing mixture (I) to carbon dioxide at a pressure in the range of from 20 to 100 bar for a time sufficient to form a gel (A), and depressurizing the gel (A). Gel (A) subsequently is exposed to a water miscible solvent (L) to obtain a gel (B), which is dried. The invention further relates to the porous materials which can be obtained in this way and the use of the porous materials as thermal insulation material, for cosmetic applications, for biomedical applications or for pharmaceutical applications.

An object of the present invention is to provide a gel material including a solvophilic polymer having a μm-scale porous structure.

A polymer gel in which solvophilic polymer units are cross-linked with each other, wherein the polymer gel contains a solvent and has a three-dimensional network structure having two regions: a first region in which the polymer units are densely present and a second region in which the polymer units are sparsely present, and a mesh size composed of the first region is from 1 to 500 μm.

A process for preparing a porous material, including the steps of providing a mixture (I) containing a composition (A) containing components suitable to form an organic gel and a solvent (B), reacting the components in the composition (A) in the presence of the solvent (B) to form a gel, and drying of the gel obtained in step b), wherein the composition (A) contains at least one compound (af) containing phosphorous and at least one functional group which is reactive towards isocyanates and at least one component (au) selected from the group consisting of urea, biuret, and derivatives of urea and biuret.

A method for manufacturing a body made of a porous material derived from precursors of the porous material in a sol-gel process, including (i) providing a mold, containing a lower part defining an interior volume for receiving the precursors of the porous material, wherein the lower part comprises a first opening, and surfaces of the lower part facing the interior volume are at least partially provided with a coating made of a material being electrically dissipative and non-sticky to the precursors of the porous material and/or the body, (ii) filling precursors of the porous material into the lower part in a first inert or ventilated region, wherein the precursors include two reactive components and a solvent, (iii) removing the body from the lower part through the first opening after a predetermined time, (iv) disposing the body onto a support, and (v) removing the solvent from the body.

Functionalized isocyanate based organic aerogel/xerogel/cryogel comprising: a cross-linked porous network structure made of polyurethane and/or polyisocyanurate and/or polyurea, comprising on their pore surface before functionalization reactive groups (B) and functionalization molecules having a solubility in water <10 g/L at 20 C. chemically attached to the pore surface of the cross-linked porous network structure wherein said molecules have at least one reactive group (A) being capable of binding to said pore surface (by reaction with groups (B)) and at least one functional group (C) providing the pore surface with the desired functionalization.

A synthesis method for making an isocyanate based organic xerogel having a low density (i.e. <400 kg/m.sup.3) and a small pore size (<150 nm) in combination with a specific surface area >100 m.sup.2/g is disclosed. The synthesis method avoiding or reducing gel shrinkage during the solvent removal step is characterized by the step wherein the organic solvent used to synthesize the isocyanate based organic xerogel is replaced by water such that during the solvent removal step only water needs to be removed to dry the porous network and to obtain the isocyanate based organic xerogel.

An aerogel that includes an open-cell structured polymer matrix that can have 5 wt. % to 50 wt. % of a polyamic amide polymer, based on the total weight of the aerogel is disclosed. The aerogel can have a density of 0.05 g/cm.sup.3 to 0.35 g/cm.sup.3 and can be thermally stable to resist browning at 330 C.

A (super)hydrophobic isocyanate based organic aerogel/xerogel/cryogel having a water contact angle of at least 90 comprising: a cross-linked porous network structure made of polyurethane and/or polyisocyanurate and/or polyurea, and hydrophobic compounds having before the gelling step at least one isocyanate-reactive group and no isocyanate groups
Characterized in that said hydrophobic compounds are covalently bonded within the porous network of the aerogel/xerogel/cryogel and wherein said bondings are created during the gelling step of the formation of the isocyanate based organic aerogel/xerogel/cryogel cross-linked porous network structure.

A composition that is self-foaming in an acid medium, and includes: at least one hydrophilic polymer, at least one compound capable of crosslinking the hydrophilic polymer by forming ionic bonds, at least one foaming agent, and at least one foam stabilizer agent; and to the use thereof as a drug, particularly for preventing and/or treating obesity.