Geopolymer-based ultraviolet-proof super-hydrophobic coating for engineering bamboo surface and preparation method of geopolymer-based ultraviolet-proof super-hydrophobic coating

Abstract

The invention relates to a geopolymer-based ultraviolet-proof super-hydrophobic coating for an engineering bamboo surface and a preparation method of the geopolymer-based ultraviolet-proof super-hydrophobic coating. Comprising the following steps: preparing fly ash-based geopolymer slurry; the method comprises the following steps: mixing a low-surface-energy substance, diatomite and a nano material in an ethanol solution according to a certain proportion, then stirring with geopolymer slurry to obtain a geopolymer super-hydrophobic coating, and coating the surface of the engineering bamboo with the geopolymer super-hydrophobic coating by adopting a brush coating or spray coating method. The geopolymer super-hydrophobic coating meets the requirement of a super-hydrophobic material, the novel inorganic coating geopolymer is utilized, the bonding strength of a coating and engineering bamboo is improved, and the geopolymer super-hydrophobic coating has excellent high-temperature resistance and bonding performance and meanwhile has the advantages of being simple in process, efficient, non-toxic, environmentally friendly, low in carbon and the like.

Description

Technical Field

[0001] The invention belongs to the field of bamboo material processing, and particularly relates to a geopolymer-based ultraviolet-proof super-hydrophobic coating for an engineering bamboo surface and a preparation method thereof. Background Art

[0002] Global warming is primarily caused by greenhouse gases (such as CO2, CO, and CH4), with CO2 being a key factor. The construction industry contributes over 8% of global CO2 emissions, and this is expected to increase further with infrastructure expansion. Therefore, the development of sustainable building materials is crucial. Bamboo and wood, traditional building materials, have regained attention due to their lightweight, high-strength, and environmentally friendly properties. However, the conflict between surging demand for wood and resource shortages, compounded by the implementation of natural forest protection policies, has further exacerbated the problem. Bamboo is considered a potential alternative to wood due to its fast growth, renewable nature, low cost, and strong rigidity. However, its natural form is limited by its small size, thin walls, and hollow core, resulting in radial variations in mechanical properties, making it difficult to meet the demands of modern construction. To overcome these limitations, researchers have developed engineered bamboo. While it exhibits excellent mechanical properties, it still suffers from issues such as water absorption, adhesion to liquids, aging and mold formation, and poor high-temperature resistance, hindering its practical application.

[0003] Research has been conducted both domestically and internationally on the preparation of superhydrophobic coatings for bamboo. Patent CN109773926A utilizes a reaction between methyl silicate and a copper-containing solution to in situ generate a polymethylsiloxane gel film on the bamboo surface, simultaneously loading it with nano-copper oxide to form a superhydrophobic coating. Patent ZL 201710032924.3 utilizes a layer-by-layer self-assembly technique to alternately deposit graphene oxide (GO) and nano-SiO2 on the bamboo surface, creating a hierarchical rough structure with a "GO skeleton-SiO2 filling." The surface is modified with fluorosilanes (such as 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane) to construct a three-dimensional network-low surface energy synergistic superhydrophobic interface. Patent CN 119144214 A utilizes a PDMS-modified epoxy resin matrix to in situ grow SiO2 on the surface of sodium montmorillonite (MMT) via a sol-gel method, forming "MMT-grafted SiO2" composite particles. The surface is modified with octadecyltrimethoxysilane (ODS) to create a superhydrophobic interface. However, these coatings all suffer from complex preparation processes, limited functionality, and environmental concerns. They also completely ignore the high-temperature and weather resistance of bamboo.

[0004] Geopolymers are gelling materials with a three-dimensional network structure, prepared from aluminosilicate precursors through alkali activation. Silicon and aluminum oxides, due to their high melting points and thermal stability, form the basis of geopolymers' high-temperature resistance. Furthermore, this three-dimensional network, stabilized by strong covalent and ionic bonds, resists thermal degradation and blocks UV penetration. Consequently, geopolymer-based superhydrophobic coatings exhibit excellent high-temperature and UV resistance. The unique spatial configuration of the PDMS molecular chains effectively scatters UV light, further enhancing the coating's UV resistance and creating a synergistic effect that increases the coating's durability in harsh environmental conditions.

[0005] The prepared geopolymer-based super-hydrophobic coating has the characteristics of high temperature resistance, UV resistance, high adhesion, high air permeability, green environmental protection, anti-fouling and anti-corrosion, and low cost, providing a scalable solution for outdoor engineering bamboo construction applications. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a geopolymer-based anti-ultraviolet super-hydrophobic coating for the surface of engineering bamboo, which has the advantages of high temperature resistance, UV protection, high adhesion, high air permeability, green environmental protection, anti-fouling and anti-corrosion, and low cost.

[0007] To achieve the above objectives, the technical solution of the present invention is:

[0008] A geopolymer-based anti-ultraviolet super-hydrophobic coating for the surface of engineered bamboo and a preparation method thereof are characterized in that: the high temperature resistance and high bonding performance of the fly ash-based geopolymer are utilized to enable the coating to be better bonded to the engineered bamboo, and the coating has excellent fire resistance while having super-hydrophobic properties. In addition, the present invention uses polydimethylsiloxane (PDMS) as a low surface energy material, and the unique spatial structure of its molecular chain can effectively disperse ultraviolet rays. In addition, the geopolymer has a three-dimensional network structure, which is relatively stable and can block the penetration of ultraviolet rays, so that it has excellent anti-ultraviolet properties. The method comprises the following steps: (1) mixing fly ash and water glass solution to obtain a fluid geopolymer slurry; (2) mixing the low surface energy material, diatomaceous earth and nanomaterial in an ethanol solution according to a certain proportion, and stirring in a magnetic stirrer for 0.5h to 1h; (3) pouring the stirred solution into the geopolymer slurry and continuing to stir; (4) pouring the prepared super-hydrophobic solution into a spray gun and spraying it on the surface of the engineered bamboo.

[0009] Furthermore, in the step (1), the water glass solution is slowly added to the fly ash and stirred, and the modulus of the water glass is 1.6 to 2.0.

[0010] Furthermore, in the step (2), the low surface energy material polydimethylsiloxane, diatomaceous earth and nano-SiO2 are added to anhydrous ethanol and stirred by a magnetic stirrer.

[0011] Furthermore, in step (3), the stirred solution is added to the fly ash geopolymer slurry and the stirring is continued.

[0012] Furthermore, in the step (4), the prepared super-hydrophobic coating solution is poured into a spray gun, and the spray gun is sprayed at a pressure of 0.15 to 0.4 MPa, wherein the total thickness of the coating is between 0.5 and 4 mm, more preferably between 2.5 and 3 mm.

[0013] Compared with the existing invention, the beneficial effects of the present invention are as follows:

[0014] This article describes a geopolymer-based, UV-resistant, super-hydrophobic coating for engineered bamboo surfaces, a new type of green building material. Designed specifically for engineered bamboo, this coating enhances its performance by imparting corrosion resistance, high-temperature resistance, and UV protection, thereby extending its service life. The formulation consists of two main components, a solid and a liquid, which are mixed before application by brush or spray. After curing, the coating bonds tightly to the substrate, forming a protective barrier against external environmental stresses.

[0015] The geopolymer-based anti-ultraviolet super-hydrophobic coating for the surface of engineering bamboo material of the present invention has abundant main raw material sources and low cost, and avoids the pollution of fluorine-containing organic matter to the environment. It is non-toxic and environmentally friendly, and is convenient for large-scale use. It is suitable for surface protection of engineering bamboo material structures.

[0016] Geopolymers have excellent high temperature resistance due to the high melting point and thermal stability of silicon and aluminum oxides in geopolymers.

[0017] The three-dimensional network structure of the geopolymer is stabilized by strong covalent and ionic bonds, which can block ultraviolet radiation penetration. In addition, the unique spatial configuration of the PDMS molecular chain can effectively scatter ultraviolet radiation, further improving the UV resistance of the coating and forming a synergistic effect.

[0018] The main component of geopolymers is a three-dimensional network of aluminosilicates. The active groups in their molecular structure (such as silanol and aluminol) can form hydrogen bonds or chemical bonds with hydroxyl groups on the surface of engineered bamboo, resulting in strong chemical adsorption. Furthermore, in engineered bamboo coatings, the geopolymer matrix penetrates the microporous structure of the bamboo surface, forming a tight interface through a dual action of mechanical anchoring and chemical bonding, significantly improving the adhesion between the coating and the substrate.

[0019] The geopolymer-based anti-ultraviolet super-hydrophobic coating of the present invention has a simple preparation process, and the coating has application advantages such as high temperature resistance, ultraviolet protection, high adhesion, high air permeability, green environmental protection, anti-fouling and anti-corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of contact angle of Example 8 of the present invention.

[0021] Figure 2 This is the surface microstructure of Example 8 of the present invention.

[0022] Figure 3 This is the microstructure of the engineering bamboo material of Example 8 of the present invention before the UV protection test.

[0023] Figure 4 This is the microstructure of the engineering bamboo material after the UV protection test of Example 8 of the present invention.

[0024] Figure 5 This is a wear test diagram of Example 8 of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in detail below with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments.

[0026] A geopolymer-based anti-ultraviolet super-hydrophobic coating for the surface of engineered bamboo and a preparation method thereof are characterized in that: the high temperature resistance and high bonding performance of the fly ash-based geopolymer are utilized to enable the coating to be better bonded to the engineered bamboo, and the coating has excellent fire resistance while having super-hydrophobic properties. In addition, the present invention uses polydimethylsiloxane (PDMS) as a low surface energy material, and the unique spatial structure of its molecular chain can effectively disperse ultraviolet rays. In addition, the geopolymer has a three-dimensional network structure, which is relatively stable and can block the penetration of ultraviolet rays, so that it has excellent anti-ultraviolet properties. The method comprises the following steps: (1) mixing fly ash and water glass solution to obtain a fluid geopolymer slurry; (2) mixing the low surface energy material, diatomaceous earth and nanomaterial in an ethanol solution according to a certain proportion, and stirring in a magnetic stirrer for 0.5h to 1h; (3) pouring the stirred solution into the geopolymer slurry and continuing to stir; (4) pouring the prepared super-hydrophobic solution into a spray gun and spraying it on the surface of the engineered bamboo.

[0027] Furthermore, in the step (1), the water glass solution is slowly added to the fly ash and stirred, and the modulus of the water glass is 1.6 to 2.0.

[0028] Furthermore, in the step (2), the low surface energy material polydimethylsiloxane, diatomaceous earth and nano-SiO2 are added to anhydrous ethanol and stirred by a magnetic stirrer.

[0029] Furthermore, in step (3), the stirred solution is added to the fly ash geopolymer slurry and the stirring is continued.

[0030] Furthermore, in the step (4), the prepared super-hydrophobic coating solution is poured into a spray gun, and the spray gun is sprayed at a pressure of 0.15 to 0.4 MPa, wherein the total thickness of the coating is between 0.5 and 4 mm, more preferably between 2.5 and 3 mm.

[0031] Example 1

[0032] Step 1: Preparation of geopolymer slurry:

[0033] 10g of water glass solid powder with a modulus of 1.6 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0034] Step 2: Prepare the modification solution:

[0035] Take 6g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them into 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0036] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0037] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0038] Example 2

[0039] Step 1: Preparation of geopolymer slurry:

[0040] 10g of water glass solid powder with a modulus of 1.8 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0041] Step 2: Prepare the modification solution:

[0042] Take 6g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0043] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0044] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0045] Example 3

[0046] Step 1: Preparation of geopolymer slurry:

[0047] 10g of water glass solid powder with a modulus of 2.0 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0048] Step 2: Prepare the modification solution:

[0049] Take 6g of polydimethylsiloxane, 0.2g of diatomaceous earth f and 0.5g of nano-SiO2, add them into 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0050] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0051] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0052] Example 4

[0053] Step 1: Preparation of geopolymer slurry:

[0054] 10g of water glass solid powder with a modulus of 1.6 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0055] Step 2: Prepare the modification solution:

[0056] Take 8g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0057] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0058] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0059] Example 5

[0060] Step 1: Preparation of geopolymer slurry:

[0061] 10g of water glass solid powder with a modulus of 1.8 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0062] Step 2: Prepare the modification solution:

[0063] Take 8g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0064] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0065] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0066] Example 6

[0067] Step 1: Preparation of geopolymer slurry:

[0068] 10g of water glass solid powder with a modulus of 2.0 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0069] Step 2: Prepare the modification solution:

[0070] Take 8g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0071] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0072] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0073] Example 7

[0074] Step 1: Preparation of geopolymer slurry:

[0075] 10g of water glass solid powder with a modulus of 1.6 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0076] Step 2: Prepare the modification solution:

[0077] Take 10g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0078] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0079] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0080] Example 8

[0081] Step 1: Preparation of geopolymer slurry:

[0082] 10g of water glass solid powder with a modulus of 1.8 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0083] Step 2: Prepare the modification solution:

[0084] Take 10g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0085] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0086] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0087] Example 9

[0088] Step 1: Preparation of geopolymer slurry:

[0089] 10g of water glass solid powder with a modulus of 2.0 was mixed with 50g of deionized water to prepare an alkali activator. 50g of fly ash was mixed with the alkali activator and stirred for 8 to 10 minutes to obtain a geopolymer slurry with good fluidity.

[0090] Step 2: Prepare the modification solution:

[0091] Take 10g of polydimethylsiloxane, 0.2g of diatomaceous earth and 0.5g of nano-SiO2, add them to 30ml of anhydrous ethanol, and stir them in a magnetic stirrer for 0.5h~1h.

[0092] Step 3: Preparation of geopolymer-based UV-resistant superhydrophobic coating

[0093] The prepared modified solution is added to the geopolymer slurry and stirred for 0.5 to 1 hour to obtain a geopolymer-based UV-resistant super-hydrophobic coating. The prepared super-hydrophobic coating solution is poured into a spray gun and sprayed onto the surface of the engineered bamboo material at a pressure of 0.15 to 0.4 MPa.

[0094] The above embodiments are only specific embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent transformations, improvements, etc. made based on the concept of the present invention without departing from the essence of the technical solution of the present invention shall be included in the protection scope of the present invention.

Claims

1. A geopolymer-based anti-ultraviolet super-hydrophobic coating for engineered bamboo surfaces and a preparation method thereof, characterized in that: The high temperature resistance and high bonding performance of fly ash-based geopolymer enable the coating to be better combined with engineering bamboo, and have excellent fire resistance while having super hydrophobic properties; in addition, the present invention uses polydimethylsiloxane (PDMS) as a low surface energy material, and the unique spatial structure of its molecular chain can effectively disperse ultraviolet rays; in addition, the geopolymer has a three-dimensional network structure, which is relatively stable and can block the penetration of ultraviolet rays, so that it has excellent anti-ultraviolet properties; the method comprises the following steps: (1) mixing fly ash and water glass solution to obtain a fluid geopolymer slurry; (2) mixing low surface energy material, diatomaceous earth and nanomaterial in an ethanol solution according to a certain proportion, and stirring in a magnetic stirrer for 0.5h to 1h; (3) pouring the stirred solution into the geopolymer slurry and continuing to stir; (4) pouring the prepared super hydrophobic solution into a spray gun and spraying it on the surface of the engineering bamboo.

2. A geopolymer-based anti-ultraviolet super-hydrophobic coating for engineering bamboo surface and a preparation method thereof according to claim 1, characterized in that: In the step (1), water glass solution is slowly added into fly ash and stirred, and the modulus of the water glass is 1.6 to 2.

0.

3. A geopolymer-based ultraviolet-proof super-hydrophobic coating for engineering bamboo surface according to claim 1 and a preparation method thereof, characterized in that: In the step (2), the low surface energy material polydimethylsiloxane, diatomaceous earth and nano-SiO2 are added to anhydrous ethanol and stirred by a magnetic stirrer.

4. A geopolymer-based anti-ultraviolet super-hydrophobic coating for engineering bamboo surface according to claim 1 and a preparation method thereof, characterized in that: In the step (3), the stirred solution is added to the fly ash geopolymer slurry and the stirring is continued.

5. A geopolymer-based anti-ultraviolet super-hydrophobic coating for engineering bamboo surface and a preparation method thereof according to claim 1, characterized in that: In the step (4), the prepared super-hydrophobic coating solution is poured into a spray gun, and the spray gun is sprayed at a pressure of 0.15 to 0.4 MPa, wherein the total thickness of the coating is between 0.5 and 4 mm, more preferably between 2.5 and 3 mm.

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