Low thermal conductivity and low-k dielectric aerogel material and preparation method therefor

A method for making a low thermal conductivity and low-k dielectric aerogel material, wherein the aerogel material comprises a pure aerogel, a fiber/aerogel composite, a polymer/aerogel composite, or a polymer/fiber/aerogel composite and the method comprising steps of:

• mixing and hydrolysis step:
• adding a siloxane precursor to an ethanol water solution to form a mixed solution and then adding an acid catalyst to the mixed solution to perform a hydrolysis reaction, wherein the siloxane precursor comprises a hydrophobic siloxane compound, a siloxane compound or a combination thereof;
• dispersion and condensation step:
• adding a dispersing solution to the mixed solution and then using an emulsifier or a stirring equipment to disperse the siloxane precursor to form a homogeneous sol, wherein the dispersing solution comprises a base catalyst;
• molding step:
• injecting the sol to a mold so as to promote the sol to further condense into a solid-like aerogel wet-gel structure, wherein the mold comprises a molding mold or a molding mold comprising a fiber;
• drying step:
• at atmospheric pressure, drying the solid-like aerogel wet-gel structure at a drying temperature so as to obtain the low thermal conductivity and low-k dielectric aerogel material with a homogeneous structure, wherein the drying temperature ranges from 60 to 150° C., the pure aerogel with thermal conductivity k ranging from 0.0113 to 0.018 W/(m·K), and the fiber/aerogel composite with thermal conductivity k ranging from 0.022 W/(m·K) to 0.032 W/(m·K);
• and
• polymer solution impregnating step:
• preparing a polymer solution and injecting the polymer solution into the low thermal conductivity and low-k dielectric aerogel material so that a polymeric chain penetrates homogeneously into interior of the low thermal conductivity and low-k dielectric aerogel material to form a polymer solution-containing pure aerogel composite or a polymer solution-containing fiber/aerogel composite, wherein the polymer solution comprises a polymer and a mixing solvent, and the polymer comprises a thermosetting polymer, a thermoplastic polymer, a liquid crystalline polymer or a combination thereof;
• and
• solvent drying step:
• placing the polymer solution-containing pure aerogel composite or the polymer solution-containing fiber/aerogel composite at a solvent drying temperature so as to vaporize the mixing solvent of the polymer solution, so that the polymer coats a network structure surface inside the pure aerogel or the fiber/aerogel composite or a fiber surface inside the fiber/aerogel composite to form the polymer/aerogel composite or the polymer/fiber/aerogel composite, wherein the solvent drying temperature ranges from 60 to 115° C.;
• wherein the polymer concentration in the polymer solution ranges from 0.01 wt % to 80.0 wt %.