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CN-121975179-A - Preparation method and application of high-transparency biological-based nanofiber aerogel heat insulation paper

CN121975179ACN 121975179 ACN121975179 ACN 121975179ACN-121975179-A

Abstract

A preparation method of high-transparency biological-based nanofiber aerogel heat insulation paper comprises the following steps of 1) heating and stirring low-acyl gellan gum powder and deionized water to dissolve to obtain gellan gum aqueous solution, 2) naturally cooling and molding the gellan gum aqueous solution obtained in the step 1) and then soaking the gellan gum aqueous solution in low-concentration divalent/trivalent metal salt solution for slow diffusion hardening to obtain hardened gum, and 3) carrying out gradient displacement soaking on the hardened gum obtained in the step 2) by adopting alcohol solvents with gradually increased volume fractions, and drying the obtained organic gel to obtain the biomass-based paper-like high-transparency aerogel. The aerogel prepared by the method realizes high-transparency paper-shaped aerogel for the first time in a gellan gum base aerogel system, and has low thermal conductivity (17.3 mW/(m.K)) under the condition of room temperature, and the transparency, low thermal conductivity and mechanical property are both considered.

Inventors

  • WANG JINBIN
  • LIU DI
  • SUN ZHIFANG
  • LI YAN

Assignees

  • 湘潭大学

Dates

Publication Date
20260505
Application Date
20260323

Claims (10)

  1. 1. A preparation method of biomass-based paper-like high-transparency aerogel is characterized in that, Step 1), heating, stirring and dissolving low-acyl gellan gum powder and deionized water to obtain gellan gum aqueous solution; Step 2), soaking the gellan gum aqueous solution obtained in the step 1) in low-concentration divalent/trivalent metal salt solution for slow diffusion hardening after natural cooling and molding to obtain hardened gum; And 3) carrying out gradient replacement soaking on the hardened glue obtained in the step 2) by adopting an alcohol solvent with gradually increased volume fraction, and drying the obtained organic gel to obtain the biomass-based paper-like high-transparency aerogel.
  2. 2. The method for preparing the biomass-based paper-like high-transparency aerogel according to claim 1, wherein the concentration of the gellan gum aqueous solution is 2-20 mg/mL.
  3. 3. The preparation method of the biomass-based paper-like high-transparency aerogel according to claim 1 is characterized in that the stirring and heating temperature of the gellan gum aqueous solution is 75-120 ℃, the stirring speed is 100-800 r/min, the low-concentration divalent/trivalent metal salt solution comprises an aluminum nitrate solution and a calcium chloride solution, and the concentration of the metal salt solution is 0.05-0.30 mol/L.
  4. 4. The method for preparing the biomass-based paper-like high-transparency aerogel according to claim 1, wherein the soaking time in the step 2) is 5-10 h.
  5. 5. The method for preparing a biomass-based paper-like highly transparent aerogel according to claim 1, wherein the organic solvent comprises one or more of ethanol solution, methanol solution and isopropanol solution. The volume concentration of the organic solvent is 70-100%.
  6. 6. The method for preparing the biomass-based paper-like high-transparency aerogel according to claim 1, wherein the soaking time in the step 3) is 1-5 times, the time is 5-10 hours, and the organic solvent needs to be replaced for each soaking.
  7. 7. The method for preparing the biomass-based paper-like highly transparent aerogel according to claim 1, wherein the drying method in the step 3) is supercritical carbon dioxide drying.
  8. 8. The preparation method of the high-transparency bio-based nanofiber aerogel heat insulation paper is characterized in that the biomass-based paper-shaped high-transparency aerogel prepared by the preparation method has a paper thickness of 0.05-2mm, a 550 nm transmittance of more than or equal to 80% and a haze of less than or equal to 20%.
  9. 9. The application of the high-transparency biological-based nanofiber aerogel heat insulation paper is characterized in that the high-transparency biological-based nanofiber aerogel heat insulation paper is prepared by the method of claim 1, and is characterized in that the biomass-based paper-shaped high-transparency aerogel is made of a transparent heat insulation material.
  10. 10. The application of the high-transparency biological-based nanofiber aerogel heat insulation paper is characterized in that the high-transparency biological-based nanofiber aerogel heat insulation paper is prepared by the method of claim 1 and is applied to novel transparent paper materials.

Description

Preparation method and application of high-transparency biological-based nanofiber aerogel heat insulation paper Technical Field The invention relates to the technical field of aerogel preparation, in particular to a high-transparency bio-based nanofiber aerogel heat insulation paper material, and a preparation method and application thereof. Background Aerogel is used as an open porous material with a three-dimensional nano structure, and has huge application potential in the fields of heat insulation, catalysis, drug release, adsorption and the like by virtue of the unique physical characteristics of low density, high specific surface area, high porosity and low thermal conductivity. However, despite these excellent properties, the lack of mechanical strength of aerogels has limited the versatility of practical use. Currently, there are relatively few aerogel materials available in the marketplace for practical use. For example, silica aerogel, while having a relatively low thermal conductivity, has poor mechanical properties and is difficult to meet the requirements of high strength applications. In contrast, organic aerogel is superior to traditional silica aerogel in terms of formability and mechanical properties, but its synthesis process is complex, and often involves toxic solvents and raw materials, which easily causes environmental pollution problems. Thus, researchers have increasingly turned their eyes toward aerogel materials based on natural polymers. Natural polymers are ideal choices for preparing aerogels due to their good biocompatibility, abundant resources, and biodegradability. However, purely natural polymer-based aerogels also suffer from insufficient mechanical properties. Therefore, how to develop an aerogel that is environmentally friendly, super-insulating and high in mechanical strength using natural polymer materials is a great challenge in the current technical field. The solution to this challenge will greatly drive the application of aerogel materials in a wider range of fields. Aerogels are nanoporous solid materials formed by gas displacement of a liquid within a gel and retention of its three-dimensional framework, often referred to as "frozen smoke" and "blue smoke" due to their lightweight and translucent appearance. Since nineties of the twentieth century, it has rapidly become an object of leading research in material science by virtue of unique properties such as extremely high porosity and specific surface area, ultra-low density, excellent heat insulation, and low dielectric constant, and has been regarded as one of advanced materials having breakthrough. The current definition of aerogels has expanded beyond the narrow scope of relying solely on supercritical drying processes in the early days to all solid materials with three-dimensional nanonetworks of colloidal particles or macromolecules, with gas-filled pores. The material generally has two key characteristics of structurally having a coherent nano skeleton and multistage pores therein to form a microscopic-to-macroscopic hierarchical porous network, and exhibiting a series of outstanding properties including ultra-high porosity (80% -99.8%), extremely high specific surface area (up to more than 2000 m < 2 >/g), extremely low density (lower than 0.003 g/cm < 3 >) and extremely low thermal conductivity (about 0.015-0.025W/(m.K)) in nature. The typical preparation process is usually based on sol-gel method to construct wet gel network, and solvent is removed by supercritical drying to maintain structural integrity. The history of this material dates back to the silica aerogel first produced in 1931 by Kistler. Today, with the development of preparation technology, aerogel has shown important application value in various fields such as heat insulation, energy saving, electrochemical energy storage, environmental adsorption, biomedicine, sensing and detection, and the like. Gellan Gum (Gellan Gum, GG) is a water-soluble anionic polysaccharide derived from Sphingomonas paucimobilis, the synthesis process starts in the cell membrane and the final product is produced extracellularly, the Gellan Gum consisting of repeating tetraose units, beta-1, 3-D-glucose, beta-1, 4-glucose and alpha-1, 4-rhamnose. The esterification reaction occurs at the C-2 and C-6 positions of (1, 3) linked D-glucose, involving L-glycerate and acetate (about 50%), respectively. GG exists in two forms, high Acyl Gellan Gum (HAGG) and Low Acyl Gellan Gum (LAGG). HAGG is the natural form of gellan gum and LAGG is extracted from HAGG by chemical treatment at elevated temperature and alkaline conditions at pH >10, in which process the ester-linked acyl groups in the glucose units are hydrolyzed and removed. GG gels when dissolved in hot water and cooled. HAGG forms a soft and elastic gel in the absence and presence of cations, while LAGG forms a hard and brittle gel, which, due to its cooling, thickening and stabilizing properties, makes gellan gum