Forest fire preventing and extinguishing gel material and preparation method thereof

Abstract

The invention discloses a forest fire prevention and extinguishment gel material and a preparation method thereof, and the forest fire prevention and extinguishment gel material comprises the following other raw materials in parts by mass: 3 parts of sodium silicate; 0.6 to 0.8 part by mass of hydroxypropyl methyl cellulose; 3-4 parts by mass of sodium bicarbonate and 1 part by mass of lauryl sodium sulfate; and 13-17 parts by volume of alkaline silica sol. The gel material provided by the invention has excellent water-retaining property, high viscosity, strong adhesive power, high foam stability and thermal stability. After combustion, a compact SiO2 carbon layer can be formed, and a lasting physical barrier is formed.

Description

Technical Field

[0001] This invention relates to the field of fire prevention and extinguishing materials, specifically, to a forest fire prevention and extinguishing gel material and its preparation method. Background Technology

[0002] In recent years, increasingly severe global climate change has increased the risk of wildfires. Faced with this severe challenge, developing efficient and reliable cutting-edge fire prevention and suppression technologies to enhance the ability to control extreme forest fires has become an urgent need in the global forest fire management field. Among these, developing new high-performance flame-retardant materials for rapidly constructing firebreaks is a key technological approach to achieving "proactive prevention" and compensating for the shortcomings of traditional methods.

[0003] In the field of chemical fire extinguishing materials, gel-based materials have attracted much attention due to their unique properties, in addition to traditional natural water, dry powder, and foam. While water, dry powder, and foam each have their applications, they also have significant drawbacks: natural water has weak adhesion and is difficult to retain for long periods; dry powder easily causes environmental pollution and has limited effectiveness in inhibiting reignition; and foam, due to its unstable structure and short duration of action, is unable to withstand the sustained high temperatures of a fire. In contrast, gel materials, especially silica-based gels formed from water glass and accelerators, exhibit practical advantages such as a wide range of raw materials and rapid gelation. However, these inorganic gels generally suffer from insufficient water retention, leading to cracking and pulverization after water loss, resulting in a significant decrease in their flame-retardant durability. On the other hand, organic polymer gels, such as systems based on sodium carboxymethyl cellulose and polyacrylamide, typically perform better in terms of water retention and mechanical strength, but their widespread application is often limited by practical problems such as high preparation costs, poor system flowability, and difficulty in penetration. Therefore, how to synergistically leverage the advantages of inorganic and organic components through material composite strategies has become an important research direction for overcoming the performance bottlenecks of single gels. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a forest fire prevention and suppression gel material and its preparation method.

[0005] The present invention adopts the following technical solution: Firstly, This invention provides a forest fire prevention and extinguishing gel material, with water accounting for 100 parts by weight, and other raw materials and their amounts as follows: sodium silicate: 3 parts by weight; hydroxypropyl methylcellulose: 0.6-0.8 parts by weight; sodium bicarbonate: 3-4 parts by weight; sodium dodecyl sulfate: 1 part by weight; alkaline silica sol: 13-17 parts by volume.

[0006] It is understood that when the unit of mass parts is g, the unit of volume parts is mL.

[0007] In some preferred embodiments, the forest fire prevention and extinguishing gel material, based on 100 parts by weight of water, includes the following other raw materials and their quantities: sodium silicate: 3 parts by weight; hydroxypropyl methylcellulose: 0.8 parts by weight; sodium bicarbonate: 3 parts by weight; sodium dodecyl sulfate: 1 part by weight; alkaline silica sol: 16-17 parts by volume.

[0008] In some preferred embodiments, the forest fire prevention and extinguishing gel material includes separately stored components A, B, and C, wherein... Composition of Material A: Sodium silicate: 3 parts by weight; Hydroxypropyl methylcellulose: 0.6-0.8 parts by weight; Water: 50 parts by weight; Composition of Material B: Sodium bicarbonate: 3-4 parts by weight; Sodium dodecyl sulfate: 1 part by weight; Water: 50 parts by weight; Composition of material C: Alkaline silica sol: 13-17 parts by volume.

[0009] In some preferred embodiments, the forest fire prevention and extinguishing gel material includes separately stored components A, B, and C, wherein... Composition of Material A: Sodium silicate: 3 parts by weight; Hydroxypropyl methylcellulose: 0.8 parts by weight; Water: 50 parts by weight; Composition of Material B: Sodium bicarbonate: 3 parts by weight; Sodium dodecyl sulfate: 1 part by weight; Water: 50 parts by weight; Composition of material C: Alkaline silica sol: 16-17 parts by volume.

[0010] In some embodiments, the viscosity of the hydroxypropyl methylcellulose is 150,000 to 250,000 mPa·s. More preferably, it is 200,000 mPa·s.

[0011] In some embodiments, the alkaline silica sol (a dispersion of silica particles with a particle size of 10-20 nm in water) has a solid content of 10-35% and a pH of 9.5-10.5.

[0012] In some preferred embodiments, the solid content of the alkaline silica sol is 30%.

[0013] Secondly, This invention provides a method for preparing the above-mentioned forest fire prevention and extinguishing gel material, comprising the following steps: (1) Sodium silicate and hydroxypropyl methylcellulose were added to a portion of deionized water and sonicated for 30 min. The sonication frequency was 25-100 kHz and the power was 30-80 W. Then, the mixture was stirred for 1-3 min at a speed of 400-600 r / min to prepare solution A, which was stored separately. (2) Add sodium bicarbonate and sodium dodecyl sulfate to the remaining deionized water, and then stir at 400-600 r / min for 5-10 min to prepare solution B; store separately; (3) The alkaline silica sol was stored separately as component C; (4) When using, add solution A, solution B and component C into a high-speed stirrer, stir and foam at a speed of 20,000 to 30,000 r / min for 1 min to prepare the forest fire prevention and extinguishing gel material.

[0014] In some embodiments, the amount of deionized water used in step (1) is 50% of the total amount of deionized water used.

[0015] In some embodiments, in step (1), the frequency of the ultrasonic treatment is 40 kHz and the power is 50 W.

[0016] Thirdly, This invention provides the application of the above-mentioned forest fire prevention and control gel material in forest fire prevention and control.

[0017] The formation of the forest fire prevention and suppression gel material of this invention is a complex process involving multiple stages and synergistic effects of multiple components. Its gelation mechanism is as follows: Figure 1 As shown.

[0018] First, the system constructs a silicon-based framework through an inorganic reaction. Sodium silicate (Na₂SiO₃) hydrolyzes in aqueous solution to produce silicate ions (such as H₃SiO₄). - When mixed with sodium bicarbonate (NaHCO3), the system is weakly alkaline (pH ≈ 9–10), which significantly promotes the condensation reaction of silicate ions. This process follows a typical sol-gel transformation pathway, where active silicic acid species gradually polymerize through intermolecular dehydration to form a three-dimensional network structure composed of siloxane bonds (Si–O–Si), thereby constructing the inorganic rigid framework of the gel.

[0019] Subsequently, the addition of hydroxypropyl methylcellulose (HPMC) introduced an organic reinforcing phase. As a nonionic cellulose ether, HPMC molecular chains are rich in hydrophilic functional groups such as hydroxyl groups, ether bonds, and hydroxypropyl groups. During mixing, these functional groups bind to the silanol groups (Si–OH) and water molecules in the inorganic silica gel network through strong hydrogen bonding. Simultaneously, the HPMC molecular chains unfold and entangle in water, forming a continuous three-dimensional physically cross-linked network. This organic network interpenetrates with the already formed inorganic silica network, initially constituting an interpenetrating network structure.

[0020] Finally, the introduction of alkaline silica sol (a stable dispersion of nano-SiO2 particles) further strengthens the gel system. Its role is mainly twofold: First, the high specific surface area of ​​the nano-SiO2 particles in the silica sol can adsorb water molecules and fill the micropores of the gel, acting as a physical filler and densifier, thereby inhibiting water diffusion. Second, under alkaline conditions, the hydroxyl groups (Si–OH) on the surface of the silica sol particles can undergo a condensation reaction with the remaining hydroxyl groups on the HPMC chain to form stable siloxane covalent bonds (Si–O–Si), thus establishing a strong "bridging" effect between the organic long chains and inorganic nanoparticles. This chemical crosslinking significantly enhances the overall network's structural strength, stability, and water retention capacity.

[0021] The present invention has the following advantages and beneficial effects: This invention aims to develop a high-performance fire-retardant gel material suitable for forest fire prevention and control scenarios. Through an organic-inorganic hybrid design, it successfully solves the core problems of traditional hydrogels, such as poor water retention, easy powdering and cracking, and insufficient flame-retardant durability. Specifically, (1) The fire-resistant gel material of the present invention exhibits the practical characteristics of rapid response, with a gelation time of only 1 to 3 minutes, which facilitates the rapid construction of isolation zones in emergency fire-fighting scenarios.

[0022] (2) The fire extinguishing gel material of the present invention has a foaming ratio of 2 to 3 times and a foam half-life of more than 24 hours, which shows excellent foaming properties and foam stability, and can ensure that the gel covers the surface evenly and maintains the heat insulation barrier for a long time.

[0023] (3) The fire-resistant gel material of the present invention has excellent water retention performance and slow water loss under high temperature environment. Thermogravimetric analysis shows that its bound water has higher thermal stability.

[0024] (4) The fire-resistant gel material of the present invention has high viscosity and an adhesion rate of over 90%, which can firmly adhere to the plant surface and resist wind and rain erosion. Its good stackability also allows it to maintain its shape on complex terrains such as slopes.

[0025] (5) The fire-resistant gel material of the present invention provides effective fire protection for wood substrates for up to 164 seconds in direct combustion tests, which is significantly better than traditional gel materials. This is due to the efficient and long-lasting physical barrier provided by the dense SiO2 carbon layer formed after combustion. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating the gelation mechanism of the forest fire prevention and extinguishing gel material of this invention.

[0027] Figure 2 The microstructures of three gel foams, namely Example 1, Comparative Example 1, and Comparative Example 2, are shown, wherein: (a) and (b) are water glass gel foams of Comparative Example 1; (c) and (d) are water glass / HPMC gel foams of Comparative Example 2; (e) and (f) are water glass / HPMC / silica sol ternary composite gel foams of Example 1.

[0028] Figure 3 Viscosity curves of three gel foams, namely Example 1, Comparative Example 1, and Comparative Example 2, are shown.

[0029] Figure 4 The stacking and adhesion properties of three types of gel foams (Example 1, Comparative Example 1, and Comparative Example 2) and their experimental flowcharts are shown.

[0030] Figure 5 Thermal stability analysis of three gel foams, namely Example 1, Comparative Example 1, and Comparative Example 2, is shown, including: (a) TG curves and (b) DTG curves.

[0031] Figure 6 Fourier transform infrared spectra of three types of gel foam, namely Example 1, Comparative Example 1, and Comparative Example 2, are shown.

[0032] Figure 7 The flame retardant performance tests of three types of gel foam, namely Example 1, Comparative Example 1, and Comparative Example 2, are shown.

[0033] Figure 8 The SEM microstructures of three gel foams after combustion are shown in Example 1, Comparative Example 1, and Comparative Example 2. Among them, (a) and (b) are water glass gel foam of Comparative Example 1; (c) and (d) are water glass / HPMC gel foam of Comparative Example 2; and (e) and (f) are water glass / HPMC / silica sol ternary composite gel foam of Example 1.

[0034] Figure 9 The XRD patterns of three types of gel foam after combustion are shown in Example 1, Comparative Example 1, and Comparative Example 2.

[0035] Figure 10 The image shows an untreated woodpile being ignited.

[0036] Figure 11 The flame-retardant effect of the wood stack covered with the gel foam of Example 1 is demonstrated.

[0037] Figure 12 The example demonstrates how gel foam extinguishes a woodpile fire in Example 1.

[0038] Figure 13 The test results showed the burning of pine needles without any treatment.

[0039] Figure 14The fire resistance test results of the gel foam of Example 1 with half of its area covered by pine needles are shown. Detailed Implementation

[0040] The embodiments of the present invention are described in detail below. These embodiments are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0042] Unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art.

[0043] In this document, when values ​​are described as ranges, it should be understood that such disclosure includes disclosure of all possible subranges within that range, as well as the specific numerical values ​​falling within that range, regardless of whether the specific numerical value or specific subrange is explicitly specified.

[0044] In this document, the terms "first aspect," "second aspect," and "third aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0045] In this document, terms such as "preferred," "more preferred," and "better" are used only to describe implementation methods or embodiments with better effects, and should be understood as not constituting a limitation on the scope of protection of this invention.

[0046] This invention aims to develop a high-performance water glass composite gel suitable for forest fire prevention and control, focusing on solving the core problems of poor water retention, easy pulverization and cracking after water loss, and insufficient flame retardant durability. This invention simultaneously introduces hydroxypropyl methylcellulose (HPMC) and alkaline silica sol into a water glass matrix composed of sodium bicarbonate and sodium silicate. HPMC and silica sol produce a synergistic effect through physical adsorption and chemical cross-linking, forming a stable "organic-inorganic" hybrid network (such as Si-OC covalent bonds), thereby significantly improving material performance. This gel exhibits excellent water retention, high viscosity, strong adhesion, and high foam stability and thermal stability. After combustion, it forms a dense SiO2 carbon layer, creating a durable physical barrier.

[0047] The performance testing methods involved in the embodiments and comparative examples of this invention are as follows: To systematically evaluate the basic properties of the prepared materials, this application conducted the following tests on the gelation time, water retention, foaming properties, stackability, adhesion, and flame retardant properties of the gel foam: (1) Gelation time determination The gelation time of the samples was determined using the tilted test tube method. A test tube containing a well-mixed gel foam was placed at room temperature, and the test tube was tilted at 45° every 10 seconds. The time when the gel foam stopped flowing was recorded as the gelation time.

[0048] (2) Water retention test After curing 80 g (W0) of gel foam, the sample was placed in a 100°C drying oven. After 5 hours, the sample was removed and weighed using an analytical balance. i The water retention rate (WR) is calculated using the following formula: WR (%) = (W i / W0) × 100% (3) Foaming performance test After the gel foam is prepared, its foam volume is measured immediately, and the time required for the foam volume to decay to half is recorded after standing, which is the foam half-life, in order to comprehensively evaluate its foaming ability and foam stability.

[0049] (4) Stackability test A polytetrafluoroethylene ring with an inner diameter of 5 cm and a height of 2 cm was placed on a pine board. The ring was filled with freshly prepared gel foam and leveled. After initial curing, the mold was carefully removed, forming a cylindrical foam body. After standing for 10 minutes, its remaining height was measured to evaluate the self-supporting ability and shape retention of the gel foam under conditions without lateral restraint.

[0050] (5) Adhesion test The newly prepared gel foam was uniformly coated onto the surface of a vertically placed pine board to form a coating with a thickness of 1 cm, and the initial mass (m) was recorded. 初 After curing for 30 minutes, weigh (m). 末 Adhesion rate (AR) is calculated using the following formula: AR (%) = [m 末 / m 初 ] × 100% (6) Combustion test Ten grams of gel foam sample were coated onto the surface of a pine board (8 cm × 8 cm), within a 5 cm × 5 cm area, with a uniform coating thickness. An alcohol torch was used, with the nozzle 5 cm from the gel foam surface, to continuously burn the sample. Timing was recorded from the moment the flame contacted the sample until the wood substrate showed obvious carbonization marks due to burning; this effective contact time of the gel foam is the carbonization time, used to characterize the gel foam's durable heat resistance.

[0051] (7) Viscosity test Viscosity testing was conducted according to GB / T 10247-2008 standard. The viscosity of the samples was measured using a digital viscometer at room temperature.

[0052] (8) Microscopic morphology analysis of gel foam: The morphology and changes of different foams at room temperature over a certain period of time were observed using a stereomicroscope (Crystal HD-4800W). During the test, fresh foam was placed in a petri dish with a diameter of 10 cm and a height of 1 cm. The morphology of the foam was photographed using a microscope at t=0 min and t=30 min. Image analysis software was then used to calculate the size distribution characteristics of the bubbles in the foam system.

[0053] (9) Thermogravimetric analysis: This experiment used a TA TGA 550 differential thermal analyzer (TTTA) to conduct thermogravimetric analysis (TGA) tests on the samples to analyze the inhibitory effect of gel foam on wood flour combustion and its own thermal stability. TGA can be used to measure the change in sample mass with temperature under programmed heating conditions in real time, thus obtaining the mass change curve of the sample with temperature. The experimental conditions were: heating range 30-800 ℃, heating rate 10 ℃ / min, and air intake rate 50 mL / min.

[0054] (10) FTIR (Full-Time Infrared Spectroscopy) The functional group structure of liquid silicone rubber was analyzed using an American infrared spectrometer. The wavenumber range was 4000-400 cm⁻¹. -1 The instrument model is Nicolet iS20, manufactured by Thermo Fisher Scientific, Inc., USA.

[0055] (11) Scanning electron microscope (SEM) The microstructure of the surface of the gel foam after combustion was observed using a ZEISS Gemini SEM 300 environmental field emission microscope (Germany). Before morphology observation, the samples were sputtered with gold for 150 s at a voltage of 5-15 kV.

[0056] (12) X-ray diffraction analysis (XRD) Crystals formed on the surface of the gel foam after combustion were analyzed using a Rigaku Ultima IV X-ray diffractometer (Japan). A copper target was used as the test target, the scanning angle range was 5-90°, and the scanning speed was 2° / min.

[0057] The following are embodiments and comparative examples of the present invention. It should be noted that the comparative examples of the present invention are not prior art, but are only set up for comparison with the embodiments and are not intended to limit the present invention.

[0058] Unless otherwise specified, the embodiments and comparative examples of this invention are based on room temperature conditions.

[0059] Example 1

[0060] The preparation method of water glass / HPMC / silica sol ternary composite gel foam includes the following steps: Weigh 3.0 g sodium silicate (Na2O·3SiO2) and 0.8 g HPMC, add them together to 50 mL of deionized water, sonicate for 30 min at a frequency of 40 kHz and a power of 50 W, and then stir at 510 r / min for 2 min to obtain solution A1. Weigh 3.0 g of sodium bicarbonate and 1.0 g of sodium dodecyl sulfate (SDS) and add them to 50 mL of deionized water. Stir at 510 r / min for 5 minutes to prepare solution B1. Take 16.67 mL of alkaline silica sol as component C1; Solution A1, solution B1 and component C1 are placed together in a high-speed stirrer at 25000r / min and stirred for 1min to produce a water glass / HPMC / silica sol ternary composite gel foam.

[0061] The viscosity of the hydroxypropyl methylcellulose is 200,000 mPa·s.

[0062] The alkaline silica sol (a dispersion of silica particles with a particle size of 10-20 nm in water) has a solid content of 30% and a pH of 9.5-10.5.

[0063] Example 2

[0064] Compared with Example 1, the difference is that the amount of sodium bicarbonate used is 4.0g, otherwise it is the same as Example 1.

[0065] Example 3

[0066] Compared with Example 1, the difference is that hydroxypropyl methylcellulose with a viscosity of 150,000 mPa·s was selected, otherwise it is the same as Example 1.

[0067] Example 4

[0068] Compared with Example 1, the difference is that hydroxypropyl methylcellulose with a viscosity of 250,000 mPa·s was selected, while the rest is the same as in Example 1.

[0069] Example 5

[0070] Compared with Example 1, the difference is that the amount of hydroxypropyl methylcellulose used in Example 5 is 0.6g, and the rest is the same as in Example 1.

[0071] Example 6

[0072] Compared with Example 1, the difference is that the amount of alkaline silica sol used in Example 6 is 13.33 mL, and the rest is the same as in Example 1.

[0073] Comparative Example 1

[0074] The preparation method of water glass gel foam includes the following steps: 3.0 g of sodium silicate was dissolved in 50 mL of deionized water and sonicated for 30 min at a frequency of 40 kHz and a power of 50 W to obtain solution A2.

[0075] Weigh 3.0 g of sodium bicarbonate and 1.0 g of sodium dodecyl sulfate (SDS) and add them to 50 mL of deionized water. Stir at 510 r / min for 5 minutes to prepare solution B1. Pour solutions A2 and B1 together into a high-speed stirrer and stir at 25000 r / min for 1 min to obtain water glass gel foam.

[0076] Comparative Example 2

[0077] The preparation method of water glass / HPMC gel foam includes the following steps: Weigh 3.0 g of sodium silicate and 0.8 g of HPMC, add them together to 50 mL of deionized water, sonicate for 30 min at a frequency of 40 kHz and a power of 50 W, and then stir at 510 r / min for 2 min to obtain solution A1. Weigh 3.0 g of sodium bicarbonate and 1.0 g of sodium dodecyl sulfate (SDS) and add them to 50 mL of deionized water. Stir at 510 r / min for 5 minutes to prepare solution B1. Solution A1 and solution B1 were placed in a high-speed stirrer at 25000r / min and stirred for 1min to obtain water glass / HPMC composite gel foam.

[0078] The viscosity of the hydroxypropyl methylcellulose is 200,000 mPa·s.

[0079] Comparative Example 3-1

[0080] Compared with Example 1, the difference is that the amount of sodium bicarbonate used is 1.0g, and the rest is the same as in Example 1.

[0081] Comparative Example 3-2 Compared with Example 1, the difference is that the amount of sodium bicarbonate used is 2.0g, otherwise it is the same as Example 1.

[0082] Comparative Example 3-3

[0083] Compared with Example 1, the difference is that the amount of sodium bicarbonate used is 5.0g, otherwise it is the same as Example 1.

[0084] Comparative Examples 3-4

[0085] Compared with Example 1, the difference is that the amount of sodium bicarbonate used is 6.0g, otherwise it is the same as Example 1.

[0086] Comparative Example 4-1

[0087] Compared with Example 1, the difference is that sodium carboxymethyl starch was used in Comparative Example 4-1 instead of hydroxypropyl methylcellulose in Example 1, and the rest is the same as Example 1.

[0088] Comparative Example 4-2

[0089] Compared with Example 1, the difference is that in Comparative Example 4-2, carboxymethyl cellulose was used instead of hydroxypropyl methyl cellulose in Example 1. After ultrasonic treatment, Comparative Example 4-2 was stirred at 510 r / min for about 10 h to dissolve it; otherwise, it was the same as Example 1.

[0090] Comparative Example 4-3

[0091] Compared with Example 1, the difference is that in Comparative Example 4-3, polyvinyl alcohol (Bohr, viscosity 20.5-24.5 mPa.s, degree of alcoholysis 87-89 mol%) was used instead of hydroxypropyl methylcellulose in Example 1. Comparative Example 4-3 was ultrasonically treated and then stirred at 510 r / min for about 2 h to dissolve it; otherwise, it was the same as in Example 1.

[0092] Comparative Example 4-4

[0093] Compared with Example 1, the difference is that in Comparative Example 4-4, carboxymethyl chitosan was used instead of hydroxypropyl methylcellulose in Example 1, while the rest is the same as in Example 1.

[0094] Comparative Example 4-5

[0095] Compared with Example 1, the difference is that in Comparative Examples 4-5, polyvinyl alcohol PVA2488 (instant soluble) was used instead of hydroxypropyl methylcellulose in Example 1, while the rest is the same as in Example 1.

[0096] Comparative Example 5-1

[0097] Compared with Example 1, the difference is that hydroxypropyl methylcellulose with a viscosity of 0.4 million mPa·s was selected, while the rest is the same as in Example 1.

[0098] Comparative Example 5-2

[0099] Compared with Example 1, the difference is that hydroxypropyl methylcellulose with a viscosity of 100,000 mPa·s was selected, otherwise the same as Example 1.

[0100] Comparative Example 5-3

[0101] Compared with Example 1, the difference is that hydroxypropyl methylcellulose with a viscosity of 300,000 mPa·s was selected, otherwise it is the same as Example 1.

[0102] Comparative Example 6-1

[0103] Compared with Example 1, the difference is that Comparative Example 6-1 uses acidic silica sol instead of alkaline silica sol in Example 1.

[0104] In Comparative Example 6-1, the amount of acidic silica sol used was 16.67 mL, the solid content of the acidic silica sol was 30%, and the pH was 2.5-3.5.

[0105] Comparative Example 6-2

[0106] Compared with Example 1, the difference is that Comparative Example 6-2 uses acidic alumina sol instead of alkaline silica sol in Example 1. The amount of acidic alumina sol used in Comparative Example 6-2 is 33.34 mL, the solid content of acidic alumina sol is 15%, and the pH is 4.0.

[0107] Comparative Example 6-3

[0108] Compared with Example 1, the difference is that Comparative Example 6-3 uses nano-silica instead of the alkaline silica sol in Example 1.

[0109] In Comparative Example 6-3, the amount of nano-silica (100±5nm) used was 5g.

[0110] Comparative Example 7-1

[0111] Compared with Example 1, the difference is that the amount of hydroxypropyl methylcellulose used in Comparative Example 7-1 is 0.1g, and the rest is the same as in Example 1.

[0112] Comparative Example 7-2

[0113] Compared with Example 1, the difference is that the amount of alkaline silica sol used in Comparative Example 7-1 is 3.33 mL, otherwise it is the same as Example 1.

[0114] Comparative Example 7-3

[0115] Compared with Example 1, the difference is that the amount of alkaline silica sol used in Comparative Example 7-3 is 26.66 mL, otherwise it is the same as Example 1.

[0116] Comparative Example 7-4

[0117] Compared with Example 1, the difference is that the amount of hydroxypropyl methylcellulose used in Comparative Example 7-4 is 1g, and the rest is the same as in Example 1.

[0118] Comparative Example 8-1

[0119] Compared with Example 1, the difference is that in Comparative Example 8-1, cetyltrimethylammonium bromide was used instead of sodium dodecyl sulfate in Example 1, otherwise the same as in Example 1.

[0120] Comparative Example 8-2

[0121] Compared with Example 1, the difference is that in Comparative Example 8-2, dodecyl dimethyl betaine was used instead of sodium dodecyl sulfate in Example 1, otherwise the same as in Example 1.

[0122] Comparative Example 8-3

[0123] Compared with Example 1, the difference is that in Comparative Examples 8-3, polyoxyethylene sorbitan monooleate was used instead of sodium dodecyl sulfate in Example 1, otherwise the same as in Example 1.

[0124] Comparative Example 8-4

[0125] Compared with Example 1, the difference is that sodium dodecylbenzenesulfonate was used instead of sodium dodecyl sulfate in Comparative Examples 8-4, otherwise the same as Example 1.

[0126] Comparative Example 8-5

[0127] Compared with Example 1, the difference is that sodium fatty alcohol polyoxyethylene ether sulfate was used in Comparative Examples 8-5 instead of sodium dodecyl sulfate in Example 1, otherwise the same as Example 1.

[0128] I. Microscopic morphology analysis: pass Figure 2 It can be seen that, although the initial bubble size (0.27 mm) of the sample in Example 1 with added HPMC and alkaline silica sol was slightly larger than that of the other two groups, its bubble size growth rate after half an hour was the lowest (44.4%), far lower than that of Comparative Example 1 (258.8%) and Comparative Example 2 (122.7%). This data indicates that the composite gelling system of Example 1 greatly inhibited the diffusion rate of gas from small bubbles to large bubbles, thereby improving the dimensional stability of the foam. The main reasons are speculated to be as follows: (1) Stabilization mechanism of HPMC: increasing viscosity and strengthening liquid film In foam systems formed by sodium bicarbonate and sodium silicate, the introduction of HPMC can delay their decay in several ways. First, the dissolution of HPMC significantly increases the viscosity of the liquid phase, which not only slows down the drainage rate within the liquid film but also significantly reduces the liquid flow rate at the Prato boundary, thus delaying the thinning of the liquid film caused by liquid accumulation at that node. Second, HPMC molecules can adsorb at the gas-liquid interface, forming an elastic viscous adsorption film. This film not only hinders bubble coalescence through steric hindrance but, more importantly, imparts significant Gibbs elasticity and Marangoni effect to the liquid film, enabling it to spontaneously repair localized thin areas caused by external disturbances, thereby effectively resisting liquid film rupture.

[0129] (2) Synergistic reinforcement of silica sol: constructing a rigid framework and stabilizing the Prato boundary However, the stabilizing effect of HPMC is essentially a physical modification. To further fundamentally alter the mechanical properties of the foam film, the introduction of alkaline silica sol plays a decisive role. The nano-sized SiO2 particles in the silica sol synergistically enhance the effect through the following pathways.

[0130] First, there's interfacial adsorption and structural inhibition. Nanoparticles can co-adsorb at the gas-liquid interface and synergize with HPMC to further enhance the steric hindrance effect and inhibit bubble coalescence. The most crucial aspect is gelation and framework construction. Under alkaline conditions, the silanol groups on the silica sol surface undergo a condensation reaction with the hydroxyl groups on the HPMC chains, forming Si-OC covalent bonds. This reaction occurs not only in the liquid film plane but also in the three-dimensional space of the Prato boundary, constructing a rigid "organic-inorganic" composite gel network framework. Finally, there's revolutionary regulation. This network framework transforms the foam's liquid structure into a robust gel state. It significantly enhances the mechanical strength of the liquid film to resist rupture. Simultaneously, the flow resistance at the gelled Prato boundary increases dramatically, almost locking the liquid in that region and nearly terminating the drainage process, thus achieving revolutionary regulation of the foam decay process.

[0131] II. Viscosity Analysis like Figure 3 As shown, the water glass / HPMC / silica sol ternary composite gel foam of Example 1 has the highest viscosity (the viscosity of the system reached 592 mPa·s at 1.5 min), while the water glass gel foam of Comparative Example 1 has the lowest viscosity.

[0132] While the introduction of sodium dodecyl sulfate (HMS) into sodium bicarbonate and sodium silicate solutions can generate foam, the system exhibits the lowest viscosity. This is because a single surfactant can only form a weak monomolecular film at the gas-liquid interface, resulting in fragile bubble walls that easily drain, leading to poor foam stability and low viscosity. When hydroxypropyl methylcellulose (HPMC) is added pre-treated, the viscosity of the foaming system increases significantly. This is because HPMC effectively delays the drainage process of the foam film by significantly increasing the bulk solution viscosity. Furthermore, its polymer chains adsorb at the interface to form a viscoelastic protective film, repairing local weak points through Gibbs elasticity and the Marangoni effect, thus strengthening the bubble structure and hindering bubble aggregation and deformation, resulting in higher flow resistance. When HPMC and alkaline silica sol are present simultaneously, the foam viscosity reaches its maximum. This is fundamentally because the silica sol nanoparticles not only act as physical fillers, but more importantly, the silanol groups on their surface undergo a condensation reaction with the hydroxyl groups on the HPMC chains under alkaline conditions, generating siloxane covalent bonds. This constructs a rigid "organic-inorganic" three-dimensional network framework at the bubble film. This structure firmly locks the bubbles in a robust gel network, greatly enhancing the mechanical strength of the liquid film and transforming the foam system from a viscoelastic liquid to a solid gel state, macroscopically exhibiting extremely high viscosity and excellent stability.

[0133] III. Stackability and Adhesion Analysis like Figure 4 As shown, the stacking and adhesion properties of different gel foams exhibit significant differences, with the performance ranking as follows: Example 1 > Comparative Example 2 > Comparative Example 1. This order clearly reveals the synergistic effect of organic polymers and nano-inorganic particles in enhancing the mechanical properties and interfacial adhesion of the gel.

[0134] Stackability of gel foam (h) 末 / h 初 This reflects the ability of the solidified network structure to resist deformation under its own weight. For Comparative Example 1, the brittle pure silica network of the water glass gel foam has low mechanical strength and is prone to brittle fracture and structural collapse under gravity, resulting in the worst stackability. In Comparative Example 2, the flexible polymer chains and rigid inorganic framework of the water glass / HPMC gel foam interpenetrate each other, forming a typical interpenetrating network structure. This structure can effectively dissipate stress through viscoelastic behavior such as the extension and retraction of molecular chains, significantly improving the gel's toughness and thus giving it better shape retention under unconstrained conditions. In Example 1, the silanol groups on the surface of the nano-SiO2 particles in the water glass / HPMC / silica sol ternary composite gel foam undergo a condensation reaction with the hydroxyl groups on the HPMC chains, forming strong Si-OC covalent bridges. This chemical crosslinking greatly enhances the stiffness and structural stability of the hybrid network, enabling it to effectively resist creep deformation caused by gravity, thereby firmly locking the foam structure and exhibiting optimal stackability (90% stackability).

[0135] Adhesion (m) 末 / m 初 The quality of the gel depends on the interfacial adhesion strength between the gel and the substrate, as well as its own cohesive strength. In Comparative Example 1, the water glass gel foam not only has weak chemical interaction with the wood surface, but also low cohesive strength, making it prone to cohesive failure when placed vertically, leading to overall detachment and exhibiting the worst adhesion. In Comparative Example 2, the abundant polar functional groups on the HPMC molecular chains of the water glass / HPMC gel foam, such as hydroxyl and ether bonds, can form a dense hydrogen bond network with the cellulose and hemicellulose on the pine wood surface, greatly enhancing interfacial adhesion. Simultaneously, the physical cross-linking of HPMC also significantly improves the gel's intrinsic cohesive strength, making it less prone to internal failure. The water glass / HPMC / silica sol ternary composite gel foam in Example 1 achieved optimal adhesion (96.66%). This is because: firstly, the chemical cross-linking of silica sol and HPMC endows the gel with extremely high cohesive strength, fundamentally eliminating the possibility of cohesive failure; secondly, under alkaline conditions, silica sol and its derived silica species may react with the hydroxyl groups on the wood surface to establish a stronger Si-OC covalent bond interface, thereby achieving a superior adhesion effect.

[0136] In summary, the introduction of HPMC significantly enhances the gel's toughness, cohesive strength, and interfacial affinity primarily through physical entanglement and hydrogen bonding; while silica sol elevates this enhancement effect to a new level by forming covalent bridges with it, together constructing a stable hybrid structure that combines high stiffness, excellent toughness, and strong interfacial adhesion.

[0137] IV. Thermogravimetric Analysis like Figure 5 As shown, in the thermogravimetric analysis, the initial mass of all samples was normalized, allowing for a pure comparison of their thermal behavior differences on the same baseline. Comprehensive analysis of the thermal behavior of the composite gel in three characteristic temperature ranges systematically reveals the intrinsic relationship between its structure and properties. In the 0–150°C range, Example 1 exhibited unique dehydration characteristics: although its TG curve showed the first weight loss, it had the highest mass retention rate, and the 70°C shoulder peak corresponding to weakly bound water in the DTG curve disappeared, with water loss concentrated in a single peak at higher temperatures. This indicates that the dense hybrid network constructed by the chemical crosslinking of silica sol and HPMC enhances the thermodynamic stability of bound water while improving water transport efficiency. This is consistent with its excellent water retention performance exhibited in the 100°C oven experiment, providing a theoretical basis for achieving a unified efficient vaporization cooling and durable barrier effect in the material.

[0138] During the medium-high temperature range of 150–400°C, Example 1 consistently maintained the highest mass retention rate. Its DTG characteristic peak shifted significantly to the right and broadened to the 300–400°C range, while the peak intensity decreased markedly. This phenomenon indicates that the introduction of Si–O–C covalent bonds significantly increased the thermal decomposition activation energy of HPMC, transforming its degradation behavior from the concentrated and violent decomposition in Comparative Example 2 to a slow and stepwise carbonization process. This extends the effective flame-retardant effect of the organic components to a higher temperature range, significantly prolonging the duration of the fire-resistant protective layer.

[0139] When the temperature exceeds 400°C, the mass curve of Example 1 tends to stabilize, and no drastic weight loss peaks like those in Comparative Examples 1 and 2 appear near 720°C. This indicates that its stable hybrid structure can effectively suppress the decomposition of byproducts and framework reconstruction at high temperatures, demonstrating structural integrity as an ultimate thermal barrier. The thermal behavior in the three stages collectively proves that the synergistic effect of HPMC and silica sol constructs a robust organic-inorganic network spanning multiple temperature scales, providing a sufficient scientific basis for this material to achieve long-term flame retardancy and structural durability in the field of forest fire prevention.

[0140] In summary, the fire-resistant gel material prepared in Example 1 of this invention has excellent water retention performance (18% water retention rate after 5 hours in a 100°C oven), slow water loss under high temperature conditions, and thermogravimetric analysis shows that its bound water has higher thermal stability.

[0141] V. Fourier Transform Infrared Spectroscopy Analysis of the Dryed Silicon-Based Cured Gel To elucidate the chemical structural evolution of the composite gel system and its correlation with performance, this application performed Fourier transform infrared spectroscopy (FTIR) analysis on the dried samples of Comparative Example 1, Comparative Example 2, and Example 1. Figure 6 As shown, by analyzing four key characteristic peaks (3500 cm⁻¹), -1 1440 cm -1 1100 cm -1 and 850 cm -1 Through a systematic comparison, the formation process of organic-inorganic hybrid networks is clearly revealed.

[0142] First, 3500 cm -1The changes in the stretching vibration peak of the nearby hydroxyl groups initially reveal the evolution of the interactions between the components. In the binary composite system of Comparative Example 2, a large number of strong and uniform hydrogen bonds are formed between HPMC and water glass, resulting in the highest absorption peak intensity and the sharpest peak shape. However, in the ternary composite system of Example 1, the intensity of this absorption peak is significantly reduced and it is markedly broadened, suggesting two aspects of structural evolution: firstly, the intervention of silanol groups on the silica sol surface reorganizes the original hydrogen bond network, increasing its diversity; secondly, some hydroxyl groups may have participated in subsequent condensation reactions, and the change in their chemical environment led to the broadening and weakening of the peak.

[0143] For 1440 cm -1 With 850 cm -1 In-depth analysis of the two characteristic peaks provided crucial evidence for the above hypothesis. (1440 cm⁻¹) -1 The absorption peak at that point originates from the carbonate ion (CO3) generated by the reaction of sodium silicate and sodium bicarbonate. 2- The systematic decrease in peak intensity from pure water glass to the ternary composite system is not due to chemical removal, but rather to the increasingly enhanced physical encapsulation and confinement of carbonate ions by the hydrogen-bonded network of HPMC (binary composite system) and the subsequently formed Si-OC covalent network (ternary composite system), thus demonstrating that the network structure is becoming increasingly dense. Meanwhile, at 850 cm⁻¹... -1 The absorption peak attributable to the Si-OH vibration provides more direct kinetic evidence: this peak is enhanced by hydrogen bonding in the binary composite system, but weakens sharply to almost disappears after the introduction of silica sol. This clearly shows that the active silanol groups (Si-OH) in the ternary composite system, as key reaction sites, are consumed in large quantities and effectively during the condensation process.

[0144] Ultimately, 1100 cm -1 The evolution of the Si-O-(Si / C) stretching vibration peak provides decisive evidence for the formation of the hybrid network. This peak, initially broad and diffuse in water glass, eventually evolves into the strongest and sharpest characteristic peak in the entire spectrum within the ternary composite system. This phenomenon proves that a dehydration condensation reaction indeed occurs between the HPMC organic phase and the silica sol inorganic phase in the ternary composite system, generating robust Si-OC covalent bonds.

[0145] In summary, the four characteristic signals from the FTIR spectrum collectively depict a complete picture of structural evolution: from physical cross-linking dominated by hydrogen bonds in a binary composite system, it has successfully evolved into an organic-inorganic hybrid three-dimensional network in a ternary composite system, with Si-OC covalent bonds as a robust framework and hydrogen bonds as a flexible supplement. This highly dense and stable interpenetrating structure can effectively lock in moisture, inhibit evaporation, and enhance the thermal stability and mechanical strength of the material, thus laying a solid microscopic foundation for the excellent and durable protective capabilities of forest fire barrier gel foam.

[0146] VI. Analysis of Gel Foam in Combustion Experiment To visually evaluate the practical flame-retardant performance of the composite gel foam, this invention tested its protective ability under continuous burning, recording the entire process and noting its morphological changes every 30 seconds until the center of the wooden board was visibly charred. Figure 7 (As shown). The results showed that there were significant differences in the effective protection time of each system, and the order was: Example 1 (164s) > Comparative Example 2 (137s) > Comparative Example 1 (100s).

[0147] In summary, the flame-retardant performance test directly and powerfully demonstrates the decisive role of silica sol in improving the flame-retardant properties of gel foam. The key mechanism lies in the fact that silica sol, through chemical cross-linking with HPMC, upgrades the toughening network, which originally relied primarily on physical action, into a rigid "organic-inorganic" hybrid framework that possesses both excellent thermal stability and structural integrity. This framework effectively resists disintegration under flame exposure, maintaining the barrier function of the protective layer, ultimately enabling the system of Example 1 to exhibit significantly superior flame-retardant durability compared to Comparative Examples 1 and 2.

[0148] VII. Morphological Analysis of Gel Foam After Combustion To investigate the mechanical behavior of the material after combustion, the carbonized surface was observed using scanning electron microscopy (SEM). Figure 8 As shown, through Figure 8 As shown in (b), the fracture surface of Comparative Example 1 is smooth and flat, exhibiting typical brittle fracture; while Figure 8 In Example 1 (f), the fracture surface is rough and uneven, exhibiting characteristics of ductile fracture. For Comparative Example 2, where the fracture morphology could not be directly obtained, its observed surface ( Figure 8 The smoothness of (d) falls between the two, indicating that its toughness is moderate. Furthermore, among the combustion residues of all systems (such as...), Figure 8 Crystalline substances were observed in (a), (c), and (e) of the samples. The specific phases of these substances will be analyzed by XRD in subsequent studies. The morphological results above indicate that the system of Example 1 can effectively improve the toughness of the material, enabling it to maintain better structural integrity after combustion.

[0149] VIII. XRD Analysis of Gel Foam After Combustion To investigate the composition of the gel foam after the combustion test and the crystals appearing on the surface of the above SEM images, XRD experiments were performed. Figure 9 As shown, the three types of gel foams after combustion in Example 1, Comparative Example 1, and Comparative Example 2 all exhibited large peaks at 10° and 20°. This is because amorphous carbon and water glass were produced during combustion, and amorphous SiO2 was generated by the decomposition of these components at high temperatures. The largest peak around 20° was observed in Example 1, indicating that it was silica aerosol produced by silica sol. According to the standard card comparison, a significant Na2CO3 diffraction peak appeared in Comparative Example 1, produced by the high-temperature decomposition of NaHCO3. Similarly, significant SiO2 diffraction peaks appeared in Comparative Example 2 and Example 1, produced by the high-temperature decomposition of water glass.

[0150] IX. Ignition Experiment (1) To test the fire resistance and flame retardant effect of the materials, a comparative experiment on the ignition of a single timber stack was conducted. For example... Figure 10 As shown in Figure 11, ignition tests were conducted using two identical 2A wood stacks. The ignition fuel used in both stacks was 1.5L of solvent oil, which was placed in a square oil pan with sides of 50cm. One of the wood stacks was left untreated (e.g., ...). Figure 10 Another timber stack was sprayed with the water glass / HPMC / silica sol ternary composite gel foam prepared in Example 1 (e.g., Figure 11 ).pass Figure 10 It can be seen that the untreated timber stacks were quickly ignited by the solvent oil pool fire. Through... Figure 11 It can be seen that the woodpile covered with the fire-retardant gel material of this application (water glass / HPMC / silica sol ternary composite gel foam of Example 1) was not ignited after the solvent oil was completely burned, indicating that the fire-retardant gel material of this application has a good fire-resistant and flame-retardant effect.

[0151] (2) To test the fire extinguishing performance of the materials, a fire extinguishing experiment was conducted on the timber stack. For example... Figure 12 As shown, a fire extinguishing test was conducted using a 6A-sized timber stack, with 2.5L of solvent oil used as ignition fuel. The solvent oil was placed in a square oil pan with sides of 60cm. Figure 12 As can be seen, after the woodpile was ignited and burned completely, the fire was quickly extinguished and did not reignite when the fire-resistant gel material of the present invention (water glass / HPMC / silica sol ternary composite gel foam of Example 1) was used for fire extinguishing, indicating that the fire-resistant gel material played a very good fire extinguishing role.

[0152] (3) To test the performance of the forest fire prevention and suppression gel material of this application in blocking the spread of forest fires, a forest fire spread inhibition experiment was conducted. The material used was pine needles. The first group of experiments, such as... Figure 13As shown, 130 catties of pine needles were used and evenly spread over an area 6m long and 3m wide. None of the pine needles underwent any flame-retardant treatment. After being ignited, the pine needles were completely burned. The second group of experiments, as shown... Figure 14 As shown, 130 catties of pine needles were evenly spread in an area 6m long and 3m wide. Half of the pine needles were covered with the water glass / HPMC / silica sol ternary composite gel foam prepared in Example 1, while the other half of the pine needles were left untreated. When the half of the pine needles without the material was ignited, the fire gradually spread. When the flames reached the pine needles covered with the fire-retardant gel material, the flames gradually extinguished and ultimately did not ignite the pine needles covered with the fire-retardant gel material, indicating that the material played a very good fire-retardant role.

[0153] In the ternary composite gel foam system of this invention, experiments were also conducted on ternary composite systems with different ratios of sodium silicate and sodium bicarbonate (Examples 1-2, Comparative Examples 3-1-3-4). The experimental results are shown in Table 1. As can be seen from Table 1, the ratio of sodium silicate to sodium bicarbonate is one of the key factors determining the overall performance of the ternary composite system. Examples 1 and 2 showed excellent overall performance in terms of gel time, expansion ratio, and foam stability, while Comparative Examples 3-1-3-4 showed a significant decrease in performance due to the imbalance of the ratio. This performance difference stems from the fundamental difference in the construction quality and reaction kinetics of the gel network structure under different ratios. The reason for this is that the reaction between sodium silicate and sodium bicarbonate is the core of the system's gelation. The bicarbonate ions in sodium bicarbonate slowly release hydrogen ions, causing the pH value of the system to gradually decrease. During this acidification process, silicate ions are protonated to generate silica monomers, and then dehydration condensation reactions occur between the silica monomers to form a three-dimensional network gel structure cross-linked by Si-O-Si covalent bonds. The reaction rate and network structure integrity of this process are directly affected by the ratio of the two components. The performance advantages of Example 1 (ratio 3:3) and Example 2 (ratio 3:4) lie in their balanced reaction kinetics and optimized network structure. When the ratio is 3:3, the amount of sodium bicarbonate added is moderate, the pH value decreases steadily, and silicate ions condense in an orderly manner, forming a uniform and dense inorganic framework. This moderate reaction rate (gel time 1.5 minutes) provides sufficient time for the HPMC molecular chains to interpenetrate with the inorganic network through hydrogen bonds. At the same time, the silanol groups on the surface of the silica sol nanoparticles undergo a condensation reaction with the hydroxyl groups on the HPMC chains, forming stable Si-OC covalent bonds. This organic-inorganic hybrid network composed of physical cross-linking (hydrogen bonds) and chemical bonding (Si-OC) enables the gel to form a dense and resilient microstructure, thus exhibiting a suitable gel time, good foaming ratio (2.6), and excellent foam stability (>24h). When the ratio is adjusted to 3:4, the proportion of sodium bicarbonate is appropriately increased, the reaction rate is accelerated (gel time 1 minute), but the uniformity of the network structure is still maintained, so the performance remains at an excellent level.

[0154] The fundamental reason for the poor performance of Comparative Examples 3-1 to 3-4 lies in the network structure defects caused by the imbalance of the ratio. In Comparative Example 3-1 (ratio 3:1), sodium bicarbonate was severely insufficient, the pH dropped too slowly, the silicate condensation reaction was sluggish, and it was difficult to form a continuous three-dimensional network, resulting in "difficulty in gelation" and poor foam stability (6h). In Comparative Example 3-2 (ratio 3:2), sodium bicarbonate was still insufficient, the gelation time was long (4.5 minutes), and the network structure was not fully developed. In Comparative Example 3-3 (ratio 3:5), sodium bicarbonate was excessive, and the sudden drop in pH caused the silicate to condense violently and instantaneously, resulting in local stress concentration and disordered aggregation, which led to a gelation time that was too short (0.2 minutes) and structural defects in the network. In Comparative Example 3-4 (ratio 3:6), sodium bicarbonate was even more excessive, the gelation time was 0.1 minutes, and there was almost no foaming, with the whole being in a colloidal state.

[0155] Table 1

[0156] In the experimental process, this invention also conducted experiments on ternary composite systems constructed from different organic polymers (Example 1, Comparative Examples 4-1 to 4-5). The experimental data results are shown in Table 2. As can be seen from Table 2, hydroxypropyl methylcellulose (HPMC) as an organic polymer component exhibits unique advantages in the ternary composite system of this application. It has a moderate gel time (1.5 minutes), a reasonable foaming ratio (2.6 times), and excellent foam stability (>24 hours), and its overall performance is rated as excellent. The reason for this is that the excellent performance of HPMC stems from the abundant hydroxyl (-OH) and ether bond (-O-) functional groups on its molecular chain. These groups can interact efficiently with the silanol groups (Si-OH) generated by the hydrolysis of sodium silicate and the surface of silica sol nanoparticles in a weakly alkaline environment. Specifically, HPMC initially interpenetrates with the inorganic silicon-oxygen network through hydrogen bond physical cross-linking. Subsequently, under alkaline conditions, its hydroxyl groups further condense with the silanol groups of silica sol to form stable Si-OC covalent bonds, thereby constructing a dense and uniform organic-inorganic hybrid three-dimensional network. This network structure not only optimizes gel dynamics, making gelation time rapid and controllable, but also enhances foam stability and foaming efficiency by increasing the elasticity and mechanical strength of the liquid film.

[0157] In contrast, the poor performance of the organic polymers in Comparative Examples 4-1 to 4-5 can be attributed to their molecular properties being incompatible with the system. Although Comparative Example 4-1 (sodium carboxymethyl starch) contains carboxyl groups, these groups ionize negatively in alkaline environments, causing electrostatic repulsion with silicate ions and hindering effective bonding, resulting in prolonged gelation time (4 minutes) and a loose network structure. Comparative Examples 4-2 (carboxymethyl cellulose) and 4-3 (polyvinyl alcohol) are difficult to dissolve (e.g., Comparative Example 4-2 requires approximately 10 hours of stirring at 510 rpm at room temperature to dissolve, and Comparative Example 4-3 requires approximately 2 hours of stirring at 510 rpm at room temperature to dissolve), indicating poor dispersibility in water, inability to uniformly participate in network construction, and a tendency to cause localized defects. Comparative Examples 4-4 (carboxymethyl chitosan) and 4-5 (polyvinyl alcohol PVA2488) showed good solubility, but their functional groups were not reactive enough or their molecular chains were too rigid, making it impossible for them to form a tight hybrid with the inorganic phase. This resulted in excessively long gelation times (13 minutes or 11 minutes), unbalanced reaction kinetics, and incomplete network development.

[0158] Table 2

[0159] In the experimental process, this invention also conducted experiments on the construction of ternary composite systems of hydroxypropyl methylcellulose with different viscosities (Example 1, Examples 3-4, Comparative Examples 5-1-5-3). The experimental results are shown in Table 3. As can be seen from Table 3: The viscosity grade of hydroxypropyl methylcellulose (HPMC) is a key parameter affecting the gel kinetics, foaming performance, and foam stability of ternary composite systems. The HPMC viscosity range (150,000-250,000) used in the embodiments of this invention achieves a good balance in terms of gel time, expansion ratio, and foam stability; while the HPMC used in the comparative examples with excessively low viscosity (e.g., 4,000) or excessively high viscosity (300,000) results in poor performance because it disrupts the formation balance of the organic-inorganic hybrid network.

[0160] Examples 1 (200,000 viscosity), 3 (150,000 viscosity), and 4 (250,000 viscosity) exhibited excellent performance, indicating that this viscosity range is an effective interval for achieving optimized balance. That is, the HPMC of the present invention (viscosity range 150,000-250,000 viscosity) achieves an optimal combination of gel kinetics, foaming characteristics, and network strength by balancing the flexibility and rigidity of the molecular chains. Example 1 (200,000 viscosity) showed the most significant performance advantages. Its gel time was moderate (1.5 minutes), providing the optimal time window for the full extension and bonding of the molecular chains; its foaming ratio was reasonable (2.6 times), indicating that its solution viscosity effectively stabilized the bubbles without hindering the foaming process; and its foam stability was excellent (>24 hours). In the system of Example 1, the HPMC molecular chains could fully play a bridging role, with the hydroxyl groups on the chains forming a moderately dense hydrogen bond network with the silanol groups generated by the hydrolysis of sodium silicate and the surface of the silica sol nanoparticles. Under alkaline conditions, a strong bond between the organic and inorganic phases was achieved through Si-OC covalent bonds. This hybrid structure, composed of flexible long chains and a rigid inorganic framework, ensures both the stretchability of the gel network (avoiding brittleness) and provides sufficient mechanical strength.

[0161] The fundamental reason for the poor performance of Comparative Examples 5-1 to 5-3 lies in the network defects caused by viscosity imbalance. In Comparative Example 5-1 (0.4K viscosity), the HPMC molecular chains, being too low in viscosity, are too short to form a continuous and effective network framework. Insufficient hydrogen bonding sites result in a significantly prolonged gelation time (14 minutes) and a loose network structure. Although the foaming ratio is high (6 times), the water retention is poor due to insufficient network strength. In Comparative Example 5-3 (300K viscosity), the HPMC molecular chains, being too high in viscosity, are too long and densely entangled, leading to excessively high system viscosity. This severely hinders bubble generation and expansion (foaming ratio is only 1.1, and foaming is difficult). Furthermore, the rapid molecular chain entanglement results in a too short gelation time (0.3 minutes), preventing the orderly construction of the network. In Comparative Example 5-2 (100K viscosity), the viscosity is still too low, the gelation time is too long (3.5 minutes), and the network construction is still insufficient.

[0162] Table 3

[0163] In the experiment, this invention also conducted experiments using ternary composite systems constructed with (alkaline silica sol, acidic silica sol, acidic alumina sol, and nano-silica) respectively (Example 1, Comparative Examples 6-1 to 6-3). The experimental results are shown in Table 4. As can be seen from Table 4: Alkaline silica sol plays an irreplaceable and crucial role in ternary composite systems. Example 1, using alkaline silica sol, exhibited a rapid and moderate gelation time (1.5 minutes), a reasonable foaming ratio (2.6 times), and excellent foam stability (>24 hours), resulting in an excellent overall performance rating. In contrast, Comparative Examples 6-1 (acidic silica sol) and 6-2 (acidic alumina sol) showed difficulty in foaming (foaming ratios of only 1.1 and 1.3), while Comparative Example 6-3 (nano silica), although capable of foaming, had an excessively long gelation time (4 minutes), resulting in poor performance. The reasons for this are: The alkaline silica sol of Example 1 exhibits high reactivity due to its chemical compatibility with other raw materials in the system. In a weakly alkaline sodium silicate / HPMC environment, the silanol groups (Si-OH) on the surface of the alkaline silica sol demonstrate high reactivity, enabling efficient bonding in two ways: firstly, it rapidly condenses with silicate ions generated from the hydrolysis of sodium silicate (Si-OH + HO-Si≡ → ​​Si-O-Si≡ + H₂O), strengthening the inorganic framework; secondly, it undergoes a condensation reaction with hydroxyl groups (C-OH) on the HPMC chains, generating strong Si-OC covalent bonds, achieving molecular-level bridging of the organic-inorganic phases. This dual bonding constructs a dense and stable hybrid network, ensuring rapid gelation and excellent performance.

[0164] In contrast, Comparative Example 6-1 (acidic silica sol) exhibits a violent neutralization reaction between its acidity (low pH) and the weak alkalinity of the sodium silicate system, leading to a sudden pH change and severely disrupting the orderly condensation process of silicate ions, making it difficult to form a complete gel network. Simultaneously, the acidic environment inhibits the dissociation and reactivity of surface silanol groups, preventing them from effectively bonding with HPMC and resulting in foaming difficulties. Comparative Example 6-2 (acidic alumina sol), in addition to the damage caused by the acidic environment, suffers from a significant difference in the chemical properties of the alumina particle surface compared to the silicate system, making it unable to participate in the formation of siloxane (Si-O-Si) or Si-OC covalent bonds, completely losing its chemical function as a nano-reinforcing phase. Comparative Example 6-3 (nano silica), being a solid powder, lacks the colloidal dispersibility and high specific surface area of ​​a sol. It is difficult to disperse uniformly in the system, readily agglomerating and failing to provide sufficient and uniformly distributed reaction sites for bonding with HPMC and sodium silicate, resulting in a slow gel reaction (4 minutes) and defective network structure.

[0165] Table 4

[0166] In the experimental process, this invention also conducted experiments with different amounts of hydroxypropyl methylcellulose and alkaline silica sol (Examples 1, 5-6, and Comparative Examples 7-1 to 7-3). The experimental results are shown in Table 5. As can be seen from Table 5: The ratio of hydroxypropyl methylcellulose (HPMC) to alkaline silica sol also plays a crucial synergistic role in the performance of the ternary composite gel. The embodiments of this invention (HPMC 0.6-0.8g, alkaline silica sol 13.33-16.67ml) achieved a good balance between gel time, expansion ratio, and foam stability. In contrast, in the comparative examples, whether HPMC was excessive (Comparative Example 7-4, 1g) or insufficient (Comparative Example 7-1, 0.1g), or alkaline silica sol was excessive (Comparative Example 7-3, 26.67ml) or insufficient (Comparative Example 7-2, 3.33ml), the performance was poor due to the disruption of the organic-inorganic hybrid network formation balance. The reason for this is: This invention (e.g., Example 1: 0.8g HPMC, 16.67ml alkaline silica sol) successfully constructed an organic-inorganic interpenetrating three-dimensional hybrid network with a rigid siloxane inorganic framework as the support, a flexible hydroxypropyl methylcellulose network as the toughening phase, and Si-OC covalent bonds as the bridge. Under this optimized ratio, the abundant hydroxyl groups (-OH) on the HPMC molecular chain tightly bind to water molecules and the inorganic phase through hydrogen bonds, providing excellent water retention. More importantly, under the alkaline environment of the system, these hydroxyl groups undergo a condensation reaction with the silanol groups (Si-OH) on the surface of the silica sol nanoparticles, generating strong Si-OC covalent bonds. The nano-SiO2 particles in the silica sol not only act as highly active crosslinking points, forming Si-O-Si and Si-OC covalent networks with HPMC and the sodium silicate matrix, greatly enhancing the mechanical strength and thermal stability of the gel; they also act as nanofillers, effectively filling the network pores and making the structure more compact. The interpenetrating network formed by this synergistic bonding gives the gel a moderate gel time (such as 1.5 minutes in Example 1), good foaming ability (such as 2.6 times that in Example 1), and excellent long-term stability (>24h).

[0167] The fundamental reason for the poor performance of the comparative examples lies in the network structure defects caused by the imbalance of dosage. Comparative Example 7-1 (HPMC 0.1g): The HPMC was severely insufficient, failing to form a continuous organic phase network to effectively bridge and toughen the brittle inorganic silica skeleton. This resulted in an excessively long gel time (7 minutes), a loose network structure, and although initial foaming was acceptable, the foam film strength was insufficient. Comparative Example 7-2 (alkaline silica sol 3.33ml): The silica sol was severely insufficient, leading to an excessively low density of key covalent cross-linking points in the system, making it difficult to form a stable hybrid network. The gel time was prolonged (4.5 minutes), resulting in poor network strength. Comparative Example 7-3 (alkaline silica sol 26.67ml): The silica sol was excessive, resulting in overly dense cross-linking points and an excessively fast reaction rate (0.6 minutes). This caused the siloxane network to shrink disorderly and violently, severely hindering bubble formation and stabilization, resulting in near-failure of foaming (1.1 times). Comparative Example 7-4 (HPMC 1g): Excess HPMC, excessive viscosity and molecular chain entanglement caused gelation to occur too quickly (0.5 minutes), which also hindered the foaming process (1.5 times).

[0168] Table 5

[0169] In the course of the experiment, this invention also conducted experiments on ternary composite systems constructed with different surface surfactants (Example 1, Comparative Examples 8-1 to 8-5). The experimental data results are shown in Table 6. As can be seen from Table 6: In Example 1 of this invention, sodium dodecyl sulfate (SDS), an anionic surfactant, was selected. In the weakly basic sodium silicate-based ternary composite system of this invention, it not only exhibited excellent foaming efficiency and foam stability, but more importantly, it enabled the system to maintain an ideal gel time window of 1-3 minutes. Example 1 (SDS) achieved an optimal balance between gel time (1.5 minutes), expansion ratio (2.6 times), and foam stability (>24 hours), resulting in an excellent overall performance rating. Other surfactants used in the comparative examples either had excessively short gel times (<1 minute, e.g., 0.2 minutes for Comparative Examples 8-1 and 8-2) or low expansion ratios (e.g., 1.3 and 1.2 expansion ratios for Comparative Examples 8-3 and 8-4), exhibiting poor performance. This may be because the electrocompatibility and molecular structure of the surfactant not only affect foaming behavior but also significantly interfere with the gelation reaction kinetics of sodium silicate and sodium bicarbonate, thus affecting the final gel time.

[0170] The superior overall performance of Example 1 of this invention lies in its optimal electrocompatibility, well-ordered molecular structure, and excellent interfacial alignment efficiency. In the weakly alkaline sodium silicate / HPMC / silica sol composite system, SDS dissolves and ionizes to generate negatively charged dodecyl sulfate ions (C...). 12 H 25 OSO3- Its negative charge causes it to react with the dominant silicate ions in the solution (such as H3SiO4). - ), OH - A strong electrostatic repulsion occurs between ions and the negatively charged silica sol nanoparticles. This electrostatic repulsion effectively prevents ineffective adsorption or flocculation of SDS molecules with inorganic components, ensuring that SDS molecules can freely and rapidly diffuse to the gas-liquid interface to perform their foaming function. More importantly, its regular straight-chain molecular structure is crucial. SDS possesses a regular twelve-carbon straight-chain hydrophobic tail and a relatively small sulfate hydrophilic head group. This molecular configuration allows for a tight, orderly directional arrangement at the gas-liquid interface, forming a robust liquid film with low surface tension and high surface elasticity. This enables it to efficiently encapsulate air under mechanical stirring, forming a large number of uniform bubbles (foaming ratio 2.6). Simultaneously, the good compatibility of SDS with the system ensures that it does not significantly interfere with the gelation reaction kinetics of sodium silicate / sodium bicarbonate, thus keeping the gelation time (1.5 minutes) within the optimal range for controllable application.

[0171] Comparative Example 8-1 (CTAB, cationic) and Comparative Example 8-2 (BS-12, zwitterionic) exhibit electrostatic complexation between their cationic or zwitterionic head groups and silicate anions, forming insoluble precipitates. This side reaction not only consumes reactants but may also lead to heterogeneous nucleation, drastically accelerating the precipitation and cross-linking process of the entire gel network. This results in an excessively short gel time (0.2 minutes), hindering both foaming and the orderly construction of the network. Comparative Example 8-3 (Tween 80, nonionic) has a gel time of 0.5 minutes and a foaming ratio of 1.5. Tween 80 suffers from structural defects leading to poor function; its hydrophobic chains contain bent double bonds, preventing molecules from tightly aligning at the bubble interface and hindering the formation of a robust liquid film, thus resulting in low foaming efficiency. Comparative Example 8-4 (sodium dodecylbenzenesulfonate, anionic), although its gel time (1.7 minutes) falls within the ideal window, indicates that it is electrically compatible with the system and does not significantly interfere with the gel reaction. However, the huge steric hindrance generated by the benzene ring structure in its molecule severely hinders the close packing and orderly arrangement of molecules at the gas-liquid interface, resulting in its ability to reduce surface tension and stabilize bubbles being far lower than that of SDS. The foaming ratio is only 1.3 times, which cannot meet the application requirements. Comparative Example 8-5 (AES, anionic type), although the gel time (1.3 minutes) is within the window, its own molecular structure defects lead to a low foaming ratio (foaming ratio 1.2). The sulfate ester bond of AES is easily hydrolyzed and ineffective in the weakly alkaline environment of the system. A large number of molecules have decomposed before foaming and lost their surface activity, resulting in weak actual foaming ability.

[0172] Table 6

[0173] Comparative Example 9-1

[0174] A3 material: Weigh 3g of sodium silicate, 0.4g of hydroxypropyl methylcellulose, 8.33ml of alkaline silica sol, and 0.5g of sodium dodecyl sulfate. Add them to 50 mL of deionized water. First, sonicate for 30 minutes at a frequency of 40kHz and a power of 50W. Then, stir at 510r / min for 5 minutes. B3 Material: Weigh 3g of sodium bicarbonate, 0.4g of hydroxypropyl methylcellulose, 8.33ml of alkaline silica sol, and 0.5g of sodium dodecyl sulfate. Add them together to 50 mL of deionized water and stir at 510 rpm for 5 minutes.

[0175] The results showed that B3 material gelled after 5 hours and could not be stored for a long time.

[0176] Comparative Example 9-2

[0177] A4 material: Weigh 3g of sodium silicate, 0.8g of hydroxypropyl methylcellulose, and 0.5g of sodium dodecyl sulfate, add them to 50 mL of deionized water, sonicate for 30 min at a frequency of 40 kHz and a power of 50 W, and then stir at 510 r / min for 5 min. B4 Material: Weigh 3g of sodium bicarbonate, 16.67ml of silica sol, and 0.5g of sodium dodecyl sulfate, add them to 50mL of deionized water, and stir at 510r / min for 5 minutes.

[0178] The results showed that B4 material gelled after 3 hours and could not be stored for a long time.

[0179] Comparative Example 9-3

[0180] A5 material: Weigh 3g of sodium silicate, 0.8g of hydroxypropyl methylcellulose and 1g of sodium dodecyl sulfate, add them to 50 mL of deionized water, sonicate for 30 min at a frequency of 40 kHz and a power of 50 W, and then stir at 510 r / min for 5 min. B5 Material: Weigh 3g of sodium bicarbonate and 16.67ml of silica sol, add them to 50mL of deionized water, and stir at 510r / min for 2 minutes.

[0181] The results showed that B5 material gelled after 3 hours and could not be stored for a long time.

[0182] In the preparation process of this invention, comparative experiments were also conducted on the construction of ternary composite gel foams using different component allocation schemes. A comparison between Example 1 and Comparative Examples 9-1 to 9-3 shows that the preparation method used in Example 1 of this invention—"premixing sodium silicate with HPMC (A1), premixing sodium bicarbonate with SDS (B1), independently mixing silica sol (C1), and finally rapidly mixing and foaming the three components"—is key to obtaining high-performance, ready-to-use gel foam products. The product prepared in Example 1 exhibits a rapid and moderate gelation time (approximately 1.5 minutes), uniform foaming, and excellent foam stability (>24 hours). In contrast, Comparative Examples 9-1 to 9-3, which used different component allocation schemes, all resulted in the precursor solution being unable to be stored (component B gelled spontaneously within 3-5 hours) and the final product exhibiting very poor performance. The reason for this is: The preparation method in Example 1 first ensures the initial activity of key components. Sodium silicate and HPMC are premixed in water (A1), providing conditions for the full hydration of HPMC and its initial hydrogen bonding with silicate ions. Sodium bicarbonate, the coagulant, is premixed with SDS, the foaming agent (B1), avoiding interference from the coagulant with other components. Most importantly, in this embodiment, the silica sol is stored independently (C1), ensuring that its nanoparticles exist in a highly dispersed and active state. Secondly, the method in Example 1 also achieves instantaneous synchronization of reaction and foaming. A1, B1, and C1 are instantaneously mixed under high-speed stirring. At this time, SDS is rapidly adsorbed to the gas-liquid interface to achieve efficient foaming; simultaneously, sodium bicarbonate and sodium silicate come into contact, triggering rapid condensation of silicate ions. During this process, the active silica sol nanoparticles and the extended HPMC chains can immediately participate in the forming three-dimensional network, achieving strong chemical hybridization through the formation of Si-OC covalent bonds. The present invention employs a process of first isolating and maintaining activity, followed by instantaneous synergy, which allows bubbles to be generated instantaneously and firmly fixed within a forming, robust organic-inorganic hybrid network, thereby obtaining foam with uniform structure and stable performance.

[0183] In Comparative Example 9-1, silica sol and sodium bicarbonate accelerator were placed together in material B3. The introduction of sodium bicarbonate disrupts the stability of the electric double layer on the surface of silica sol nanoparticles, leading to rapid agglomeration, sedimentation, and even pre-gelation of the particles. This deactivates the particles before formal mixing, preventing them from playing their core role in nano-reinforcement and chemical cross-linking.

[0184] Comparative Examples 9-2 and 9-3 premixed silica sol with the coagulant sodium bicarbonate in component B. This resulted in the same consequence as Comparative Example 9-1: premature deactivation of the silica sol. Even with correct HPMC distribution, the final gel formed was merely a fragile, incomplete network due to the lack of chemical cross-linking by the silica sol, and the precursor solution could not be stored due to localized reactions.

[0185] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0186] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A forest fire prevention and extinguishing gel material, characterized in that: The forest fire prevention and extinguishing gel material, based on 100 parts by weight of water, includes the following other raw materials and their quantities: sodium silicate: 3 parts by weight; hydroxypropyl methylcellulose: 0.6-0.8 parts by weight; sodium bicarbonate: 3-4 parts by weight; sodium dodecyl sulfate: 1 part by weight; alkaline silica sol: 13-17 parts by volume.

2. The forest fire prevention and extinguishing gel material according to claim 1, characterized in that: The forest fire prevention and extinguishing gel material, based on 100 parts by weight of water, includes the following other raw materials and their quantities: sodium silicate: 3 parts by weight; hydroxypropyl methylcellulose: 0.8 parts by weight; sodium bicarbonate: 3 parts by weight. Sodium dodecyl sulfate: 1 part by weight; alkaline silica sol: 16-17 parts by volume.

3. The forest fire prevention and extinguishing gel material according to claim 1, characterized in that: The forest fire prevention and extinguishing gel material includes separately stored components A, B, and C, wherein... Composition of Material A: Sodium silicate: 3 parts by weight; Hydroxypropyl methylcellulose: 0.6-0.8 parts by weight; Water: 50 parts by weight; Composition of Material B: Sodium bicarbonate: 3-4 parts by weight; Sodium dodecyl sulfate: 1 part by weight; Water: 50 parts by weight; Composition of material C: Alkaline silica sol: 13-17 parts by volume.

4. The forest fire prevention and extinguishing gel material according to claim 3, characterized in that: The forest fire prevention and extinguishing gel material includes separately stored components A, B, and C, wherein... Composition of Material A: Sodium silicate: 3 parts by weight; Hydroxypropyl methylcellulose: 0.8 parts by weight; Water: 50 parts by weight; Composition of Material B: Sodium bicarbonate: 3 parts by weight; Sodium dodecyl sulfate: 1 part by weight; Water: 50 parts by weight; Composition of material C: Alkaline silica sol: 16-17 parts by volume.

5. A forest fire prevention and extinguishing gel material according to any one of claims 1-4, characterized in that: The viscosity of the hydroxypropyl methylcellulose is 150,000 to 250,000 mPa·s; preferably 200,000 mPa·s.

6. A forest fire prevention and extinguishing gel material according to any one of claims 1-4, characterized in that: The alkaline silica sol has a solid content of 10-35% and a pH of 9.5-10.5; preferably, the alkaline silica sol has a solid content of 30%.

7. A method for preparing the forest fire prevention and extinguishing gel material according to any one of claims 1-6, characterized in that: Includes the following steps: (1) Sodium silicate and hydroxypropyl methylcellulose were added to a portion of deionized water and sonicated for 30 min. The sonication frequency was 25-100 kHz and the power was 30-80 W. Then, the mixture was stirred for 1-3 min at a speed of 400-600 r / min to prepare solution A, which was stored separately. (2) Add sodium bicarbonate and sodium dodecyl sulfate to the remaining deionized water, and then stir at 400-600 r / min for 5-10 min to prepare solution B; Save separately; (3) The alkaline silica sol was stored separately as component C; (4) When using, add solution A, solution B and component C into a high-speed stirrer, stir and foam at a speed of 20,000 to 30,000 r / min for 1 min to prepare the forest fire prevention and extinguishing gel material.

8. The method for preparing the forest fire prevention and extinguishing gel material according to claim 7, characterized in that: The amount of deionized water used in step (1) is 50% of the total amount of deionized water used.

9. The method for preparing the forest fire prevention and extinguishing gel material according to claim 7, characterized in that: In step (1), the frequency of ultrasonic treatment is 40kHz and the power is 50W.

10. The application of forest fire prevention and suppression gel materials in forest fire prevention and suppression, characterized in that, The forest fire prevention and extinguishing gel material is the forest fire prevention and extinguishing gel material according to any one of claims 1-6 or the forest fire prevention and extinguishing gel material prepared by any one of claims 7-9.

Images