Fused aerogel-polymer composite, methods of manufacture thereof and articles comprising the same
Disclosed herein is a method of preparing a fused aerogel-polymer composite in which aerogel and an organic polymer is mixed in a dry state to adsorb polymer particles on the surface of the aerogel and are then subjected to thermal treatment, thus forming a polymer coating on the aerogel. The fused aerogel-polymer composite can be used for thermal insulation in a variety of applications. The fused aerogel-polymer composite exhibits high thermal insulation properties and superior physical strength and processability while still maintaining the properties of an aerogel that does not have a polymer coated on its surface.
1. A method of preparing a fused polymer-coated aerogel comprising:
mixing an inorganic aerogel with organic polymer particles to form an aerogel-polymer composite; the organic polymer particles having an average particle size of about 1 to about 100 micrometers;
heat treating the aerogel-polymer composite to form a fused aerogel-polymer composite; wherein mixing the inorganic aerogel with the organic polymer particles is performed by dry blending such that the organic polymer particles adhere to a surface of the inorganic aerogel by electrostatic forces; wherein the heat treating is conducted at a temperature of about 50 to about 100° C. higher than a flow point or a melting point of the organic polymer for a period of time of about 1 minute to about 10 hours.
2. The method of claim 1 , wherein the organic polymer particles have a melting point of about 100° C. to about 400° C.
3. The method of claim 1 , wherein the organic polymer particles are selected from the group consisting of a thermoplastic polymer, a thermosetting polymer, a blend of a thermoplastic polymer, a blend of thermosetting polymers, a blend of thermoplastic polymers with thermosetting polymers, homopolymers, copolymers, terpolymers, ionomers, dendrimers, semi-crystalline polymers, amorphous polymers, hydrophobic polymers, hydrophilic polymers, and a combination comprising at least one of the foregoing organic polymers.
4. The method of claim 1 , wherein the organic polymer is a crystalline hydrophilic polymer.
5. The method of claim 1 , wherein the crystalline hydrophilic polymer is selected from the group consisting of polyvinylalcohol, polyvinylacetate, polyvinylpyrrolidone, polystyrene sulfonic acid neutralized with sodium salt, polyethylene oxide, and a combination comprising at least one of the foregoing crystalline hydrophilic polymers.
6. The method of claim 1 , wherein the organic polymer particles comprise a crystalline hydrophobic polymer.
7. The method of claim 6 , wherein the crystalline hydrophobic polymer is selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polytetrafluoroethylene, polystyrene, polyvinylchloride, and a combination comprising at least one of the foregoing crystalline hydrophobic polymers.
8. The method of claim 1 , wherein the aerogel and the organic polymer particles are present in a volume ratio of about 1:1 to about 1:3.
9. The method of claim 1 , wherein aerogel is blended with the organic polymer particles in a ball mill, a jet mill, a Henschel mixer, a Waring blender, a drum mixer, a ribbon mixer, a vertical spiral mixer, a Muller mixer, a sigma mixer, a chaotic mixer, a single screw extruder, a multiple screw extruder, or a combination comprising at least one of the foregoing mixers.
10. The method of claim 1 , further comprising molding the fused aerogel-polymer composite to form a monolith.