Aerogel thermal insulation mat and preparation method thereof
The present application discloses an aerogel thermal insulation mat and a preparation method thereof. The thermal insulation mat is prepared by coating a surface of a fiber mat with a composite slurry, followed by sintering. The composite slurry is prepared from raw materials including a functionalized silica aerogel, an inorganic silicate-modified resin, chopped glass fibers and a dual coupling agent in specific percents by weight. The dual coupling agent allows the chopped glass fibers and the functionalized silica aerogel to form an interwoven network structure, thereby enhancing the interfacial bonding force. The functionalized silica aerogel reduces water absorption and improves structural compactness. The thermal insulation mat obtained exhibits optimized mechanical properties and enhanced tear resistance; reinforced structural stability and significantly reduced powder shedding rate; and excellent water resistance with a three-dimensional protective structure formed, thereby providing a technical support for the application in complex environments.
1 . A composite slurry, wherein the composite slurry comprises the following components in percent by weight:
18%-22% of a functionalized silica aerogel;
32%-38% of an inorganic silicate-modified resin;
3%-5% of chopped glass fibers;
0.3%-0.5% of a dual coupling agent;
0.3%-0.5% of a nanoclay dispersion;
0.1%-0.3% of a defoamer;
0.2%-0.6% of a wetting agent;
0.5%-1.0% of at least one of methyltrimethoxysilane or vinyltrimethoxysilane; and
a balance of water.
2 . The composite slurry according to claim 1 , wherein the dual coupling agent is prepared from a silane coupling agent and a titanate coupling agent at a weight ratio of (1-3):1.
3 . The composite slurry according to claim 1 , wherein the dual coupling agent is prepared from γ-aminopropyltriethoxysilane and pyrophosphate-type monoalkoxy titanate at a weight ratio of 2:1.
4 . The composite slurry according to claim 1 , wherein the inorganic silicate-modified resin is a sodium silicate-modified phenolic resin.
5 . The composite slurry according to claim 1 , wherein the functionalized silica aerogel is prepared by using β-cyclodextrin (β-CD), a silane coupling agent, silica sol, aminoadamantane and halloysite nanotubes (HNTs).
6 . The composite slurry according to claim 5 , wherein a mass ratio of the aminoadamantane to the silane coupling agent to the silica sol is 1:1:(20-30); a mass ratio of the β-CD to the HNTs is 1:(20-30).
7 . The composite slurry according to claim 6 , wherein a method for preparing the functionalized silica aerogel comprises the following steps:
S1, premixing the aminoadamantane and the silane coupling agent to obtain a premix; then, adding the premix to the silica sol and stirring to form an “aminoadamantane-silica sol” complex;
S2, preparing a saturated aqueous solution of the β-CD, and mixing the saturated aqueous solution of the β-CD with the HNTs to form a “β-CD-HNTs” complex; and
S3, mixing the “aminoadamantane-silica sol” complex with the “β-CD-HNTs” complex and stirring to form a wet gel; and
drying the wet gel to obtain the functionalized silica aerogel.
8 . The composite slurry according to claim 1 , wherein raw materials for preparing the functionalized silica aerogel comprise:
halloysite nanotubes;
at least one of dodecyl methacrylate or pentafluorophenyl methacrylate; and
silica sol with a SiO 2 content of 25%.
9 . The composite slurry according to claim 1 , wherein a method for preparing the composite slurry comprises the following steps:
T1, preparing raw materials according to the weight percent of each component;
T2, mixing and dispersing the water, the inorganic silicate-modified resin and the functionalized silica aerogel to form a homogeneous base material;
T3, adding the chopped glass fibers and the nanoclay dispersion to the homogeneous base material, performing shear dispersion, and then adding the dual coupling agent and stirring to obtain a mixture; and
T4, adding the at least one of the methyltrimethoxysilane or the vinyltrimethoxysilane, the defoamer and the wetting agent to the mixture, and adjusting a viscosity of a resulting slurry to 25-30 mPa·s and a pH value of the resulting slurry to 9-9.5 to obtain the composite slurry.
10 . An aerogel thermal insulation mat, wherein the aerogel thermal insulation mat is prepared by coating the composite slurry according to claim 1 on a fiber mat, followed by sintering.
11 . The aerogel thermal insulation mat according to claim 10 , wherein the fiber mat is one of a glass fiber mat, a carbon fiber mat, a nickel fiber mat, a stainless steel fiber mat, an aluminum silicate fiber mat, a ceramic fiber mat, an alumina fiber mat, a basalt fiber mat or a polyacrylonitrile fiber mat.
12 . The aerogel thermal insulation mat according to claim 10 ,
wherein a thickness of the fiber mat is 0.5 mm to 500 mm.
13 . A method for preparing the aerogel thermal insulation mat according to claim 10 , wherein the method comprises the following steps:
(1) pre-wetting the fiber mat to obtain a pre-wet fiber mat;
(2) placing the pre-wet fiber mat in an environment with a vacuum degree of −0.08 MPa to −0.1 MPa, and impregnating the composite slurry so that a penetration amount of the composite slurry reaches pores of the fiber mat; then, controlling a coating amount of the composite slurry on a surface of the fiber mat to be 1000-1200 g/m 2 ·mm by means of extrusion to obtain an impregnated fiber mat;
(3) sintering the impregnated fiber mat;
(4) performing surface hydrophobization treatment; and
(5) performing drying to obtain the aerogel thermal insulation mat.
14 . The aerogel thermal insulation mat according to claim 13 , wherein the surface hydrophobization treatment in the step (4) uses an emulsion containing a mixture of silane and siloxane with a volume concentration of 5% as a hydrophobing agent.