Preparation method of hydrophobic flame-retardant cellulose foam material
By mixing sugarcane bagasse fiber and bamboo fiber and modifying it with stearate ester, combined with the method of coating hollow glass microspheres with alkyl ketene dimers, the hydrophilicity and flammability problems of fiber-based foam materials were solved, and a cellulose foam material with hydrophobic and flame-retardant properties was prepared, realizing an efficient and environmentally friendly material replacement for petroleum-based plastic foam.
Patent Information
- Application Number
- CN202510790388.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-11-14
AI Technical Summary
Existing fiber-based foam materials, due to their strong hydrophilicity and flammability, cannot meet the packaging and transportation requirements in high humidity environments and for flammable and explosive hazardous materials.
A hydrophobic and flame-retardant cellulose foam material was prepared by mixing sugarcane bagasse fiber and bamboo fiber, modifying the cellulose through stearate esterification, physically coating hollow glass microspheres with alkyl ketene dimers, and then combining polyvinyl alcohol and sodium dodecyl sulfate with high-speed stirring and foaming.
The prepared material has good hydrophobic and flame-retardant properties, high mechanical strength, is green and safe, and the process is simple and efficient.
Smart Images
Figure CN120944174A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new material preparation technology, and in particular to a method for preparing a hydrophobic and flame-retardant cellulose foam material. Background Technology
[0002] Petroleum-based plastic foams are widely used in various fields due to their low cost and excellent cushioning performance. However, the environmental pollution and non-degradable hazards generated during the production and processing of petroleum-based plastics have become urgent problems to be solved. Therefore, plant-based foam materials made from cellulose have emerged. These are new porous materials with low density, good performance, and are environmentally friendly and renewable, and are expected to replace plastic foams in many fields. However, due to the characteristics of cellulose materials, fiber-based foam materials have high hygroscopicity and flammability, which makes them unsuitable for packaging and transporting flammable and explosive hazardous materials in high-humidity environments.
[0003] In view of the above, it is necessary to study a fiber-based foam material with good hydrophobic and flame-retardant properties to solve the above-mentioned application scenarios and technical problems. Summary of the Invention
[0004] The main objective of this invention is to provide a method for preparing hydrophobic and flame-retardant cellulose foam materials, which aims to solve the problems of strong hydrophilicity and flammability of current fiber-based foam materials. Furthermore, the preparation method of this invention has the advantages of being simple, efficient, green, safe, and having stable performance.
[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a hydrophobic and flame-retardant cellulose foam material, comprising the following steps: (1) Sugarcane bagasse fiber and bamboo fiber are mixed in a certain proportion to obtain mixed plant fiber; (2) Add stearic acid (SA) powder to anhydrous ethanol, heat and stir until the stearic acid powder dissolves to obtain anhydrous ethanol solution of stearic acid; (3) The mixed plant fibers in step (1) are mixed with the anhydrous ethanol solution of stearic acid in step (2) and then subjected to esterification reaction. After the reaction is completed, the filter cake is collected by filtration to obtain modified cellulose. (4) The alkyl ketene dimer (AKD) emulsion was mixed with hollow glass microspheres (HGMs) and reacted. After the reaction was completed, the modified hollow glass microspheres were obtained by separation. (5) Add polyvinyl alcohol (PVA) powder and glycerin to deionized water, heat and stir until the polyvinyl alcohol powder is completely dissolved to obtain a polyvinyl alcohol solution; (6) Modified cellulose, modified hollow glass microspheres, polyvinyl alcohol solution and sodium dodecyl sulfate (SDS) are mixed and stirred at high speed. After foaming by high-speed stirring, fiber-based foam material wet foam is obtained. (7) Filter out excess water from the wet foam of the fiber-based foam material in step (6) at room temperature, and then dry the foam of the fiber-based foam material to obtain hydrophobic and flame-retardant plant-based fiber foam material.
[0006] Preferably, the ratio of bagasse fiber to bamboo fiber in step (1) is one of 7:3, 5:5 or 3:7.
[0007] Preferably, the mass-to-volume ratio of stearic acid powder to anhydrous ethanol in step (2) is 0.05-0.2:1 g / mL; and the heating temperature is 70-90 ℃.
[0008] Preferably, in step (3), the mass-to-volume ratio of the mixed plant fiber to the anhydrous ethanol solution of stearic acid is 0.25:1; the temperature of the esterification reaction is 50~90 ℃ and the time is 20~100 min.
[0009] Preferably, the solid content of the alkyl ketene dimer emulsion in step (4) is 15±0.5%; the mass-to-volume ratio of the hollow glass microspheres to the alkyl ketene dimer emulsion is 1:1-3 g / mL.
[0010] Preferably, in step (5), the volume ratio of glycerol to deionized water is 0.01:1; the total volume ratio of polyvinyl alcohol powder to glycerol and deionized water is 0.025-0.05:1 g / mL; and the heating temperature is 80-100℃.
[0011] Preferably, the mass ratio of modified cellulose, modified hollow glass microspheres and sodium dodecyl sulfate in step (6) is 1:1:0.3, and the mass-volume ratio of the total amount of modified cellulose, modified hollow glass microspheres and sodium dodecyl sulfate to the polyvinyl alcohol solution is 23:100 g / mL.
[0012] Preferably, the stirring rate of the high-speed stirring in step (6) is 2800-3000 rad / min, and the stirring time is 9-11 min.
[0013] Preferably, the drying temperature in step (7) is 70~90 ℃ and the drying time is 10~12 h.
[0014] The beneficial effects of this invention are as follows: 1. This invention modifies cellulose by hydrophobic esterification using SA as a modifying agent, which not only has the characteristics of being green, safe, and environmentally friendly, but also has the advantages of being non-toxic, low-cost, and easy to operate.
[0015] 2. This invention constructs a core-shell structure with an external hydrophobic layer by physically coating HGMs with AKD. This not only solves the problem of reduced hydrophobicity of foamed materials after the addition of inorganic glass microspheres, but also makes the prepared foamed materials have good flame retardancy and mechanical strength.
[0016] 3. The preparation process of this invention is simple, green, safe, and the reaction conditions are mild. The prepared fiber-based foamed material is a biodegradable multifunctional foamed material with good hydrophobic properties, flame retardant properties, and mechanical strength. Attached Figure Description Figure 1 The water contact angle diagrams are shown for the hydrophobic flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 of this invention. Figure 2 The images shown are SEM images of the hydrophobic and flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 of this invention. Figure 3 The compression stress-strain curves of the hydrophobic flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 of this invention are shown. Figure 4 The HRR and THR are those of the hydrophobic flame-retardant cellulose foam material prepared in Example 1 of this invention. Detailed Implementation
[0017] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.
[0018] To verify the early crack-resistant properties and other effects of the early crack-resistant hydraulic concrete of the present invention, a comparative test was conducted between the early crack-resistant hydraulic concrete of the present invention and existing concrete. There are many actual embodiments, but only the following representative embodiments are selected.
[0019] Example 1 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a ratio of 7:3 to obtain mixed plant fiber.
[0020] (2) Add 5 g of SA powder to 50 mL of anhydrous ethanol and heat and stir at 80 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0021] (3) Pour 10 g of mixed plant fiber and 50 mL of SA anhydrous ethanol solution into a container and stir to allow it to react at 80 °C. After reacting for 80 min, filter and collect the modified cellulose.
[0022] (4) Mix 20 mL of AKD emulsion with a solid content of 15±0.5% with 10 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0023] (5) Add 4 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 90 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0024] (6) Put 10 g of modified cellulose, 10 g of modified HGMs, 100 mL of PVA solution and 3 g of SDS into the container of a high-speed mixer, set the mixing speed of the machine to 3000 rad / min, and perform high-speed mixing and foaming for 10 min to obtain wet foam of fiber-based foam material.
[0025] (7) Pour the prepared wet foam into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 80 °C to dry for 12 h to obtain hydrophobic flame retardant cellulose foam material.
[0026] The HRR and THR of the hydrophobic flame-retardant cellulose foam material prepared in this embodiment are as follows: Figure 4 As shown, by Figure 4 It can be seen that this fiber foam material has a good flame retardant effect, with low HRR and THR values. Furthermore, the HRR results show that the foam material has a long ignition time (9s) and is difficult to ignite.
[0027] Example 2 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a ratio of 7:3 to obtain mixed plant fiber.
[0028] (2) Add 5 g of SA powder to 30 mL of anhydrous ethanol and heat and stir at 80 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0029] (3) Pour 10 g of mixed plant fiber and 50 mL of SA anhydrous ethanol solution into a container and stir to allow it to react at 80 °C. After reacting for 80 min, filter and collect the modified cellulose.
[0030] (4) Mix 10 mL of AKD emulsion with a solid content of 15±0.5% with 10 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0031] (5) Add 4 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 90 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0032] (6) Put 10 g of modified cellulose, 10 g of modified HGMs, 100 mL of PVA solution and 3 g of SDS into the container of a high-speed mixer, set the mixing speed of the machine to 3000 rad / min, and perform high-speed mixing and foaming for 10 min to obtain wet foam of fiber-based foam material.
[0033] (7) Pour the wet foam into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 80 ℃ to dry for 12 h to obtain hydrophobic flame retardant cellulose foam material.
[0034] Example 3 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a ratio of 7:3 to obtain mixed plant fiber.
[0035] (2) Add 5 g of SA powder to 30 mL of anhydrous ethanol and heat and stir at 80 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0036] (3) Pour 10 g of mixed plant fiber and 50 mL of SA anhydrous ethanol solution into a container and stir to allow it to react at 80 °C. After reacting for 80 min, filter and collect the modified cellulose.
[0037] (4) Mix 30 mL of AKD emulsion with a solid content of 15±0.5% with 10 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0038] (5) Add 4 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 90 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0039] (6) Put 10 g of modified cellulose, 10 g of modified HGMs, 100 mL of PVA solution and 3 g of SDS into the container of a high-speed mixer, set the mixing speed of the machine to 3000 rad / min, and perform high-speed mixing and foaming for 10 min to obtain wet foam of fiber-based foam material.
[0040] (7) Pour the wet foam into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 80 ℃ to dry for 12 h to obtain hydrophobic flame retardant cellulose foam material.
[0041] The water contact angle diagrams of the hydrophobic flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 are shown below. Figure 1 As shown, by Figure 1 It can be seen that this cellulose foam material has good hydrophobic properties. In Example 3, its water contact angle (WCA) can reach up to 140.2°, indicating that it is a hydrophobic material.
[0042] SEM images of the hydrophobic and flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 are shown below. Figure 2 As shown, by Figure 2 It can be seen that the hollow glass microspheres (HGMs) modified by the alkyl ketene dimer (AKD) emulsion are closely connected with the cellulose matrix, and a relatively obvious AKD-coated outer membrane structure can be observed in Example 1, which indicates that the physical coating of AKD was successfully carried out.
[0043] The compressive stress-strain curves of the hydrophobic flame-retardant cellulose foam materials prepared in Examples 1, 2, and 3 are shown below. Figure 3 As shown, by Figure 3 It can be seen that this hydrophobic and flame-retardant fiber foam material has good mechanical properties, with high compression modulus and compression strength.
[0044] Example 4 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a 5:5 ratio to obtain mixed plant fiber.
[0045] (2) Add 7.5 g of SA powder to 30 mL of anhydrous ethanol and heat and stir at 70 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0046] (3) Pour 10 g of mixed plant fiber and 50 mL of SA anhydrous ethanol solution into a container and stir to allow it to undergo esterification reaction at a temperature of 50 °C. After reacting for 100 min, filter and collect the modified cellulose.
[0047] (4) Mix 30 mL of AKD emulsion with a solid content of 15±0.5% with 10 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0048] (5) Add 4.5 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 100 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0049] (6) Put 10 g of modified cellulose, 10 g of modified HGMs, 100 mL of PVA solution and 4 g of SDS into the container of a high-speed mixer, set the mixing speed of the machine to 2800 rad / min, and perform high-speed mixing and foaming for 9 min to obtain wet foam of fiber-based foam material.
[0050] (7) Pour the wet foam into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 90 ℃ to dry for 10 h to obtain hydrophobic flame retardant cellulose foam material.
[0051] Example 5 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a 5:5 ratio to obtain mixed plant fiber.
[0052] (2) Add 7.5 g of SA powder to 30 mL of anhydrous ethanol and heat and stir at 80 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0053] (3) Pour 10 g of mixed plant fiber and 50 mL of SA anhydrous ethanol solution into a container and stir. Let it undergo esterification reaction at a temperature of 90 °C. After reacting for 100 min, filter and collect to obtain modified cellulose.
[0054] (4) Mix 20 mL of AKD emulsion with a solid content of 15±0.5% with 8 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0055] (5) Add 4 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 90 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0056] (6) Put 10 g of modified cellulose, 10 g of modified HGMs, 100 mL of PVA solution and 2 g of SDS into the container of a high-speed mixer, set the mixing speed of the machine to 3000 rad / min, and perform high-speed mixing and foaming for 10 min to obtain wet foam of fiber-based foam material.
[0057] (7) Pour the wet foam into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 80 ℃ to dry for 10 hours to obtain hydrophobic flame retardant cellulose foam material.
[0058] Example 6 The method for preparing hydrophobic and flame-retardant cellulose foam material provided in this embodiment includes the following steps: (1) Control the total mass of the oven-dried fiber to 10 g, and mix the sugarcane bagasse fiber and bamboo fiber evenly in a ratio of 3:7 to obtain mixed plant fiber.
[0059] (2) Add 5 g of SA powder to 30 mL of anhydrous ethanol and heat and stir at 80 °C until the SA powder is completely dissolved to obtain an anhydrous ethanol solution of SA.
[0060] (3) Pour the mixed plant fiber prepared in step (1) and the anhydrous ethanol solution of SA prepared in step (2) into a container and stir it to allow it to undergo esterification reaction at a temperature of 90 °C. After reacting for 60 min, filter and collect to obtain modified cellulose.
[0061] (4) Mix 10 mL of AKD emulsion with a solid content of 15±0.5% with 6 g of HGMs and stir until the solution does not have obvious stratification. Then, use equipment to filter the solution to separate AKD modified HGMs.
[0062] (5) Add 3 g of PVA powder and 1 mL of glycerol to deionized water, heat and stir at 90 °C until the PVA powder is completely dissolved to obtain a PVA solution.
[0063] (6) The modified cellulose, modified HGMs, PVA solution and 2 g of SDS are put into the container of a high-speed mixer. The mixing speed of the machine is set to 3000 rad / min. After high-speed mixing and foaming for 10 min, wet foam of fiber-based foam material can be obtained.
[0064] (7) Pour the wet foam prepared in step (6) into a mold with a filter screen at the bottom, filter out the excess water in the system at room temperature, and then transfer the foam to an oven at 70 ℃ to dry for 10 h to obtain hydrophobic flame retardant cellulose foam material.
[0065] In summary, this invention utilizes SA as a modifying agent to perform hydrophobic esterification modification of cellulose, which not only possesses green, safe, and environmentally friendly characteristics but also offers advantages such as non-toxicity, low cost, and simple operation. By physically coating HGMs with AKD, a core-shell structure with an external hydrophobic layer is constructed. This not only solves the problem of reduced hydrophobicity in foamed materials after the addition of inorganic glass microspheres but also enables the prepared foamed material to exhibit good flame retardancy and mechanical strength.
[0066] The specific embodiments of the invention have been described in detail above, but these are merely examples, and the invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the invention are also within the scope of this invention. Therefore, all equivalent transformations, modifications, and improvements made without departing from the spirit and principles of this invention should be included within the scope of this invention.
Claims
1. A method for preparing a hydrophobic and flame-retardant cellulose foam material, characterized in that, Includes the following steps: (1) Sugarcane bagasse fiber and bamboo fiber are mixed in a certain proportion to obtain mixed plant fiber; (2) Add stearic acid powder to anhydrous ethanol, heat and stir until the stearic acid powder dissolves to obtain an anhydrous ethanol solution of stearic acid; (3) After mixing the mixed plant fiber in step (1) with the stearic acid anhydrous ethanol solution in step (2), the mixture is subjected to esterification reaction. After the reaction is completed, the filter cake is collected by filtration to obtain modified cellulose. (4) The alkyl ketene dimer emulsion was mixed with hollow glass microspheres and reacted. After the reaction was completed, the modified hollow glass microspheres were obtained by separation. (5) Add polyvinyl alcohol powder and glycerin to deionized water, heat and stir until the polyvinyl alcohol powder is completely dissolved to obtain a polyvinyl alcohol solution; (6) Modified cellulose, modified hollow glass microspheres, polyvinyl alcohol solution and sodium dodecyl sulfate are mixed and stirred at high speed. After foaming by high-speed stirring, fiber-based foam material wet foam is obtained. (7) Filter out excess water from the wet foam of the fiber-based foam material in step (6) at room temperature, and then dry the foam of the fiber-based foam material to obtain hydrophobic and flame-retardant plant-based fiber foam material.
2. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, The ratio of bagasse fiber to bamboo fiber in step (1) is one of 7:3, 5:5 or 3:
7.
3. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, The mass-to-volume ratio of stearic acid powder to anhydrous ethanol in step (2) is 0.05-0.2:1 g / mL; the heating temperature is 70~90 ℃.
4. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, In step (3), the mass-to-volume ratio of the mixed plant fiber to the anhydrous ethanol solution of stearic acid is 0.25:1; the temperature of the esterification reaction is 50~90℃ and the time is 20~100 min.
5. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, The solid content of the alkyl ketene dimer emulsion in step (4) is 15±0.5%; the mass-to-volume ratio of hollow glass microspheres to the alkyl ketene dimer emulsion is 1:1-3 g / mL.
6. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, In step (5), the volume ratio of glycerol to deionized water is 0.01:1; the total volume ratio of polyvinyl alcohol powder to glycerol and deionized water is 0.025-0.05:1 g / mL; and the heating temperature is 80-100℃.
7. The preparation method of the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, The mass ratio of modified cellulose, modified hollow glass microspheres and sodium dodecyl sulfate in step (6) is 1:1:0.3, and the mass-volume ratio of the total amount of modified cellulose, modified hollow glass microspheres and sodium dodecyl sulfate to the polyvinyl alcohol solution is 23:100 g / mL.
8. The method for preparing the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, The stirring rate of the high-speed stirring in step (6) is 2800-3000 rad / min, and the stirring time is 9-11 min.
9. The method for preparing the hydrophobic flame-retardant cellulose foam material as described in claim 1, characterized in that, In step (7), the drying temperature is 70~90 ℃ and the drying time is 10~12 h.