Preparation method of bamboo fiber reinforced silica aerogel sound absorption material
The method of preparing silica aerogel reinforced with bamboo fiber solves the problem of weak mechanical properties of silica aerogel, achieves high flexural strength and excellent sound absorption performance, simplifies the process and reduces solvent usage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SAIC GM WULING AUTOMOBILE CO LTD
- Filing Date
- 2024-04-11
- Publication Date
- 2026-06-09
AI Technical Summary
Silica aerogels have weak mechanical properties and are easily broken, leading to the collapse of their porous structure and reduced sound absorption performance. Furthermore, existing reinforcement methods are complex and require a large amount of solvent.
The preparation method of bamboo fiber reinforced silica aerogel includes steps such as high temperature and high pressure cooking, ultrasonic treatment, alkaline treatment, hydrophobic modification and supercritical drying, which form a porous structure and improve the hydrophobicity and mechanical properties of the material.
It significantly improves the bending strength and sound absorption performance of the material, reduces the risk of pore collapse, and increases the sound insulation of 100-5000Hz. The material is environmentally friendly and the process is simplified.
Smart Images
Figure CN118324488B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sound-absorbing materials technology, specifically to a method for preparing a bamboo fiber-reinforced silica aerogel sound-absorbing material. Background Technology
[0002] Silica aerogel is a porous material with low density and light weight, exhibiting good sound absorption properties. However, it has weak mechanical properties and is prone to breakage, leading to the collapse of its porous structure and a reduction in sound absorption performance. Silica aerogel can be reinforced by extracting nanocellulose, but this process is complex and involves the use of numerous solvents.
[0003] Silica aerogel is a three-dimensional, tortuous solid network structure formed by the Si-O-Si bonds connecting and stacking nanoparticles. Its internal network voids contain over 90% gaseous media, thus possessing unique performance characteristics. In the preparation of silica aerogel, if the liquid and solid in the wet gel are separated through a simple evaporation process, the aerogel will shrink and severely crack and collapse during drying due to capillary pressure. However, by using supercritical drying technology to replace the liquid component in the wet gel with gas, the problem of cracking and collapse during drying has been successfully solved. The large-scale market application of silica aerogel is still limited by several factors, such as its inherent ceramic brittleness and difficulty in molding. Improving the mechanical properties of silica aerogel hinges on enhancing the connectivity and strength of the aerogel framework. Density is the primary factor affecting mechanical properties; other parameters include the synthesis conditions and microstructure of the aerogel material. Methods to enhance mechanical properties mainly include extending the aging time, introducing a reinforcing second phase to prepare composite materials, organic crosslinking of silica with polymers, and introducing organosilicon precursors.
[0004] Nanocellulose aerogels possess excellent sound absorption properties due to their high porosity. When sound in the air passes through the cellulose aerogel, it vibrates within the pores. Due to the viscosity of the air, the sound energy is converted into internal energy and dissipated, thus achieving a sound absorption effect. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing a bamboo fiber reinforced silica aerogel sound-absorbing material, which has a good sound absorption effect.
[0006] The technical solution of this invention is implemented as follows:
[0007] This invention provides a method for preparing a bamboo fiber reinforced silica aerogel sound-absorbing material, comprising the following steps:
[0008] S1. Extraction of bamboo fiber: bamboo sections of equal length are cut into bamboo strips, washed and soaked in deionized water, and then subjected to high temperature and high pressure cooking. After cooking, the strips are first treated with an ultrasonic wave, then mechanically rolled and separated into fibers, and then vacuum dried and mechanically combed and cut to length to obtain bamboo fiber raw material.
[0009] S2. Alkali treatment and silicon source addition of bamboo fiber: Soak the prepared bamboo fiber in alkaline silicon source treatment solution for 50-70 minutes to obtain mixed treatment solution 1;
[0010] S3. Acidification treatment of the treatment solution: Slowly add 35-45wt% oxalic acid solution to the mixed treatment solution 1, adjust the pH value of the solution to 3-4, stir for 4-5 hours to obtain mixed treatment solution 2;
[0011] S4. Preparation of bamboo fiber wet gel by alkaline solution catalysis: Sodium hydroxide solution was added to the mixed treatment solution 2 as an alkaline catalyst, the pH value of the solution was adjusted to 9-10, the mixed solution was allowed to stand for 4-5 hours, and the bamboo fiber reinforced silica wet gel was obtained after filtration.
[0012] S5. Solvent replacement, aging and hydrophobic modification of wet gel: The surface of bamboo fiber reinforced silica wet gel was sprayed with a hexane solution containing trimethylchlorosilane at a spraying speed of 0.5-0.8 L / min, an ambient temperature of 50-55℃, and a spraying time of 1-2 h. After treatment, the wet gel was soaked in hexane for 3-4 h and then washed to obtain hydrophobically modified wet gel.
[0013] S6. Drying wet gel to produce aerogel: Supercritical drying is performed on the hydrophobic modified wet gel to obtain bamboo fiber reinforced silica aerogel sound-absorbing material.
[0014] As a further improvement of the present invention, the high-temperature and high-pressure cooking treatment in step S1 is performed at a temperature of 120-135°C, a treatment time of 12-14 hours, and a treatment pressure of 0.14-0.19 MPa.
[0015] As a further improvement of the present invention, the ultrasonic treatment in step S1 has a power of 120-140w, a frequency of 50-70KHz, a treatment temperature of 60-70℃, and a treatment time of 1-2h.
[0016] As a further improvement of the present invention, the bamboo fiber in step S1 has a length of 80-120 mm and a diameter of 0.5-0.7 mm.
[0017] As a further improvement of the present invention, the alkaline silicon source treatment solution in step S2 is composed of the following raw materials in parts by weight: 180-220 parts of sodium silicate, 30-50 parts of sodium bicarbonate, and 800-1000 parts of deionized water.
[0018] As a further improvement of the present invention, the weight ratio of bamboo fiber to alkaline silicon source treatment solution in step S2 is 1:3-6.
[0019] As a further improvement of the present invention, the concentration of the hexane solution of trimethylchlorosilane in step S5 is 0.5-0.8 wt%, and the weight ratio of the hexane solution to the wet gel is 18-22:1.
[0020] The present invention has the following beneficial effects:
[0021] 1. Deionized water is pressure-cooked to remove some water-soluble impurities, and ultrasonic treatment further separates bamboo fiber impurities and promotes the formation of a porous structure in bamboo fibers, which improves the interface bonding between silica aerogel and bamboo fibers and enhances the sound absorption performance of the material.
[0022] 2. The alkaline treatment solution provides a silicon source for aerogel preparation and can further dissolve residual impurities in bamboo fiber;
[0023] 3. Hydrophobic modification solution can reduce solution waste by spraying the surface hydrophobic modification solution. The environment created by spraying makes the hydrophobic modification of the material more effective in reducing the water absorption rate of the material and reducing the weakening of sound absorption performance caused by the collapse of material pores due to water absorption.
[0024] 4. Bamboo fibers have a high number of hydroxyl groups on their surface, resulting in silica aerogels with high porosity and good sound absorption performance.
[0025] 5. Bamboo fiber is natural, environmentally friendly, and biodegradable;
[0026] 6. The sound insulation of bamboo fiber reinforced silica aerogel in the 100-5000Hz range is 9.45-46.82dB, which is significantly improved compared with the sound insulation of nanocellulose reinforced silica aerogel in the 100-5000Hz range of 2.9-5.3dB.
[0027] 7. The flexural strength of bamboo fiber reinforced silica aerogel is significantly improved compared with that of nano bamboo cellulose reinforced silica aerogel. The high flexural strength can reduce the problem of reduced sound absorption performance caused by pore collapse during application. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is a scanning electron microscope image of bamboo fiber.
[0030] Figure 2 Scanning electron microscope image of bamboo fiber-reinforced silica aerogel. Detailed Implementation
[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0032] Example 1
[0033] A method for preparing a bamboo fiber-reinforced silica aerogel sound-absorbing material includes the following steps:
[0034] S1. Extraction of bamboo fiber: Bamboo segments of equal length are split into bamboo strips, washed, and then immersed in deionized water. The strips are then subjected to high-temperature and high-pressure steaming at 135℃ for 14 hours and 0.19 MPa. After steaming, the strips undergo ultrasonic treatment at 140W power, 70kHz frequency, 70℃, and 2 hours. Following this, the strips are mechanically rolled and separated into fibers, then vacuum dried and mechanically combed and cut to length to obtain bamboo fiber raw material. The bamboo fiber length is 80-120 mm and the diameter is 0.5-0.7 mm.
[0035] S2. Alkali treatment and silicon source addition of bamboo fiber: The prepared bamboo fiber is soaked in an alkaline silicon source treatment solution for 70 minutes to obtain mixed treatment solution 1, wherein the alkaline silicon source treatment solution includes 220g sodium silicate, 50g sodium bicarbonate and 1000g deionized water, and the weight ratio of bamboo fiber to alkaline silicon source treatment solution is 1:5.
[0036] S3. Acidification treatment of the treatment solution: Slowly add 35wt% oxalic acid solution to the mixed treatment solution, adjust the pH value of the solution to 4, stir for 5h to obtain mixed treatment solution 2;
[0037] S4. Preparation of bamboo fiber wet gel by alkaline solution catalysis: Sodium hydroxide solution was added to the mixed treatment solution 2 as an alkaline catalyst, the pH value of the solution was adjusted to 10, the mixed solution was allowed to stand for 4 hours, and the bamboo fiber reinforced silica wet gel was obtained after filtration.
[0038] S5. Solvent replacement, aging and hydrophobic modification of wet gel: The surface of bamboo fiber reinforced silica wet gel was sprayed with a hexane solution containing 0.8 wt% trimethylchlorosilane. The weight ratio of hexane solution to gel was 20:1, the spray flow rate was 0.5 L / min, the ambient temperature was 55℃, and the spraying time was 2 h. After treatment, the gel was soaked in hexane for 4 h and then washed to obtain hydrophobically modified wet gel.
[0039] S6. Drying wet gel to produce aerogel: Supercritical drying is performed on the hydrophobic modified wet gel to obtain bamboo fiber reinforced silica aerogel sound-absorbing material.
[0040] Example 2
[0041] A method for preparing a bamboo fiber-reinforced silica aerogel sound-absorbing material includes the following steps:
[0042] S1. Extraction of bamboo fiber: Bamboo segments of equal length are split into bamboo strips, washed, and then immersed in deionized water. The strips are then subjected to high-temperature and high-pressure steaming at 120℃ for 12 hours and 0.14 MPa. After steaming, the strips undergo ultrasonic treatment at 120W power, 50kHz frequency, 60℃, and 1 hour. Following this, the strips are mechanically rolled and separated into fibers, then vacuum dried and mechanically combed and cut to length to obtain bamboo fiber raw material. The bamboo fiber length is 80-120 mm and the diameter is 0.5-0.7 mm.
[0043] S2. Alkali treatment and silicon source addition of bamboo fiber: The prepared bamboo fiber is soaked in an alkaline silicon source treatment solution for 50 minutes to obtain mixed treatment solution 1, wherein the alkaline silicon source treatment solution includes 180g sodium silicate, 30g sodium bicarbonate and 800g deionized water, and the weight ratio of bamboo fiber to alkaline silicon source treatment solution is 1:5.
[0044] S3. Acidification treatment of the treatment solution: Slowly add 45wt% oxalic acid solution to the mixed treatment solution 1, adjust the pH value of the solution to 3, stir for 4h to obtain mixed treatment solution 2;
[0045] S4. Preparation of bamboo fiber wet gel by alkaline solution catalysis: Sodium hydroxide solution was added to the mixed treatment solution 2 as an alkaline catalyst, the pH value of the solution was adjusted to 9, the mixed solution was allowed to stand for 5 hours, and the bamboo fiber reinforced silica wet gel was obtained after filtration.
[0046] S5. Solvent replacement, aging and hydrophobic modification of wet gel: The surface of bamboo fiber reinforced silica wet gel was sprayed with a hexane solution containing 0.5 wt% trimethylchlorosilane. The weight ratio of hexane solution to gel was 20:1, the spray flow rate was 0.5 L / min, the ambient temperature was 50℃, and the spraying time was 1 h. After treatment, the gel was soaked in hexane for 3 h and then washed to obtain hydrophobically modified wet gel.
[0047] S6. Drying wet gel to produce aerogel: Supercritical drying is performed on the hydrophobic modified wet gel to obtain bamboo fiber reinforced silica aerogel sound-absorbing material.
[0048] Example 3
[0049] A method for preparing a bamboo fiber-reinforced silica aerogel sound-absorbing material includes the following steps:
[0050] S1. Extraction of bamboo fiber: Bamboo segments of equal length are split into bamboo strips, washed, and then immersed in deionized water. The strips are then subjected to high-temperature and high-pressure steaming at 130℃ for 13 hours and 0.16 MPa. After steaming, the strips undergo ultrasonic treatment at 130W power, 60kHz frequency, 65℃, and 1 hour. Following this, the strips are mechanically rolled and separated into fibers, then vacuum dried and mechanically combed and cut to length to obtain bamboo fiber raw material. The bamboo fiber length is 80-120 mm and the diameter is 0.5-0.7 mm.
[0051] S2. Alkali treatment and silicon source addition of bamboo fiber: The prepared bamboo fiber is soaked in an alkaline silicon source treatment solution for 60 minutes to obtain mixed treatment solution 1, wherein the alkaline silicon source treatment solution includes 200g sodium silicate, 40g sodium bicarbonate and 1000g deionized water, and the weight ratio of bamboo fiber to alkaline silicon source treatment solution is 1:5.
[0052] S3. Acidification treatment of the treatment solution: Slowly add 40% oxalic acid solution to the mixed treatment solution, adjust the pH value of the solution to 4, stir for 4 hours to obtain mixed treatment solution 2;
[0053] S4. Preparation of bamboo fiber wet gel by alkaline solution catalysis: Sodium hydroxide solution was added to the mixed treatment solution 2 as an alkaline catalyst, the pH value of the solution was adjusted to 9, the mixed solution was allowed to stand for 4 hours, and the bamboo fiber reinforced silica wet gel was obtained after filtration.
[0054] S5. Solvent replacement, aging and hydrophobic modification of wet gel: The surface of bamboo fiber reinforced silica wet gel was sprayed with a hexane solution containing 0.6 wt% trimethylchlorosilane. The weight ratio of hexane solution to gel was 20:1, the spray flow rate was 0.5 L / min, the ambient temperature was 50℃, and the spraying time was 2 h. After treatment, the gel was soaked in hexane for 3 h and then washed to obtain hydrophobically modified wet gel.
[0055] S6. Drying wet gel to produce aerogel: Supercritical drying is performed on the hydrophobic modified wet gel to obtain bamboo fiber reinforced silica aerogel sound-absorbing material.
[0056] Comparative Example 1:
[0057] The only difference between this comparative example and Example 1 is that bamboo fiber is replaced with nano-bamboo cellulose. The extraction methods for nano-bamboo cellulose differ from those for bamboo fiber. Nano-bamboo cellulose is obtained from bamboo powder, a byproduct of the bamboo fiber extraction process, and has a diameter of 250-300 nm.
[0058] Table 1 shows the test data of Examples 1-3 and Comparative Example 1. From the test results, the bamboo fiber reinforced silica aerogel material prepared by the present invention has significantly improved bending strength and deformation resistance compared with the nano bamboo cellulose reinforced aerogel material. In terms of sound absorption performance, the sound absorption coefficient is not much different, but the sound insulation is greatly improved.
[0059] Table 1
[0060]
[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a bamboo fiber-reinforced silica aerogel sound-absorbing material, characterized in that, Includes the following steps: S1. Extraction of bamboo fiber: Bamboo segments of equal length are split into bamboo strips, washed, and then immersed in deionized water for high-temperature and high-pressure cooking. After cooking, the strips are first subjected to ultrasonic treatment, then mechanically rolled and separated into fibers, and finally vacuum dried and mechanically combed and cut to length to obtain bamboo fiber raw material. The high-temperature and high-pressure cooking treatment temperature is 120-135℃, the treatment time is 12-14h, and the treatment pressure is 0.14-0.19MPa. S2. Alkali treatment and silicon source addition of bamboo fiber: Soak the prepared bamboo fiber in alkaline silicon source treatment solution for 50-70 minutes to obtain mixed treatment solution 1; S3. Acidification treatment of the treatment solution: Slowly add 35-45wt% oxalic acid solution to the mixed treatment solution 1, adjust the pH value of the solution to 3-4, stir for 4-5 hours to obtain mixed treatment solution 2; S4. Preparation of bamboo fiber wet gel by alkaline solution catalysis: Sodium hydroxide solution was added to the mixed treatment solution 2 as an alkaline catalyst, the pH value of the solution was adjusted to 9-10, the mixed solution was allowed to stand for 4-5 hours, and the bamboo fiber reinforced silica wet gel was obtained after filtration. S5. Solvent replacement, aging and hydrophobic modification of wet gel: The surface of bamboo fiber reinforced silica wet gel was sprayed with a hexane solution containing trimethylchlorosilane at a spraying speed of 0.5-0.8 L / min, an ambient temperature of 50-55℃, and a spraying time of 1-2 h. After treatment, the wet gel was soaked in hexane for 3-4 h and then washed to obtain hydrophobically modified wet gel. S6. Drying wet gel to produce aerogel: Supercritical drying is performed on the hydrophobic modified wet gel to obtain bamboo fiber reinforced silica aerogel sound-absorbing material.
2. The preparation method according to claim 1, characterized in that, The ultrasonic treatment in step S1 has a power of 120-140W, a frequency of 50-70KHz, a treatment temperature of 60-70℃, and a treatment time of 1-2h.
3. The preparation method according to claim 1, characterized in that, The bamboo fiber in step S1 has a length of 80-120 mm and a diameter of 0.5-0.7 mm.
4. The preparation method according to claim 1, characterized in that, The alkaline silicon source treatment solution in step S2 is composed of the following raw materials in parts by weight: 180-220 parts sodium silicate, 30-50 parts sodium bicarbonate, and 800-1000 parts deionized water.
5. The preparation method according to claim 1, characterized in that, The weight ratio of bamboo fiber to alkaline silicon source treatment solution in step S2 is 1:3-6.
6. The preparation method according to claim 1, characterized in that, In step S5, the concentration of the hexane solution of trimethylchlorosilane is 0.5-0.8 wt%, and the weight ratio of the hexane solution to the wet gel is 18-22:1.