A foam stabilizer and its preparation method and application

Abstract

The present invention belongs to the field of papermaking technology, and discloses a foam stabilizer, a preparation method thereof, and an application thereof. The foam stabilizer comprises the following components in parts by weight: 12.5 to 125 parts of bacterial cellulose dispersion, 1 to 10 parts of surfactant, and 1000 to 2000 parts of water, wherein the mass concentration of the bacterial cellulose dispersion is 0.5 to 1%. The preparation method of the foam stabilizer comprises the following steps: adding the bacterial cellulose dispersion to water, stirring, adding the surfactant, and stirring to obtain the foam stabilizer. The foam stabilizer prepared by the present invention is green and environmentally friendly, and the bacterial cellulose presents a unique ribbon shape. With the help of electrostatic attraction, it can be adsorbed on the surface of bubbles generated by the surfactant over a large area, thereby strengthening the close arrangement between the surfactants and also hindering the desorption of the surfactants. The addition of the foam stabilizer helps to enhance the tensile strength and tear resistance of the fiber preform.

Description

Technical Field

[0001] The present invention belongs to the technical field of papermaking, and relates to a foam stabilizer, a preparation method and an application thereof, and in particular to a foam stabilizer capable of enhancing the strength of a fiber preform in foam molding, a preparation method and an application thereof. Background Art

[0002] High-performance composites generally consist of a matrix and reinforcement materials, with reinforcement materials being a key component of high-performance composites, increasing strength and improving performance. High-performance composites must use high-performance fibers and two- and three-dimensional fabrics made from these fibers as reinforcements, such as alumina fibers and fiber preforms. However, high-performance inorganic fibers have hydrophobic and highly inert surface properties, making fiber bundles difficult to unbundle during dispersion and molding. Furthermore, the lack of hydrogen bonding between inorganic fibers results in a loose structure and low strength in the molded material, impacting the uniformity and performance of the fiber preform.

[0003] Foam molding technology is a molding method that can improve the molding properties of inorganic fibers. Unlike traditional wet and dry molding processes, it uses foam as a fiber dispersion medium, achieving uniform dispersion and molding of different fiber types. Therefore, foam stability is crucial to foam molding technology and the molded preforms, directly affecting the performance and internal structure of the finished product. Therefore, to address issues such as easy foam breakage, loose fiber preform structure, and low strength during the foam molding process, there is an urgent need to develop a method or product that both stabilizes the foam and enhances the strength of the fiber preform. Summary of the Invention

[0004] The present invention addresses issues such as easy foam breakage, loose fiber preform structure, and low strength during foam molding. Its primary purpose is to provide a foam stabilizer that enhances the strength of fiber preforms during foam molding. The ultra-long bacterial cellulose filaments in the foam stabilizer coat the surface of bubbles generated by the surfactant and fill the gaps between the surfactants, hindering thinning of the liquid film and surfactant desorption, thereby enhancing foam stability. Simultaneously, some surfactants and bacterial cellulose adhere to the fiber surface, creating hydrophilic groups on the fiber surface. This generates hydrogen bonding forces between the fibers, increasing the structural strength of the fiber preform.

[0005] Another object of the present invention is to provide a method for preparing the foam stabilizer.

[0006] Another object of the present invention is to provide use of the above foam stabilizer in the preparation of fiber preforms.

[0007] Another object of the present invention is to provide a fiber preform.

[0008] To achieve the above object, the technical solution of the present invention is as follows:

[0009] A foam stabilizer, comprising the following components in parts by weight:

[0010] 12.5-125 parts bacterial cellulose dispersion

[0011] 1-10 parts surfactant

[0012] 1000-2000 parts of water;

[0013] The mass concentration of the bacterial cellulose dispersion is 0.5-1%.

[0014] Preferably, the foam stabilizer comprises the following components in parts by weight:

[0015] 12.5-50 parts bacterial cellulose dispersion

[0016] 1 to 6 parts surfactant

[0017] 1000 parts water.

[0018] Preferably, the bacterial cellulose dispersion is obtained by treating bacterial cellulose with 1 wt.% to 5 wt.% NaOH solution and then dispersing it at high speed.

[0019] Preferably, the treatment time of 1 wt.% to 5 wt.% NaOH solution is at least 20 min, the diameter of the bacterial cellulose is 20 to 150 nm, and the length is greater than 20 μm.

[0020] Preferably, the surfactant is at least one of dodecyldimethylamine oxide, sodium dodecylbenzenesulfonate, and hexadecyltrimethylammonium bromide.

[0021] A preparation method of a foam stabilizer comprises the following steps: adding bacterial cellulose dispersion into water, stirring at 300-500 rpm for 5-10 minutes, adding a surfactant, and continuing to stir uniformly to obtain the foam stabilizer.

[0022] Application of the above foam stabilizer in the preparation of fiber preforms.

[0023] Preferably, the application comprises the following steps:

[0024] After high-performance inorganic fiber, polyester fiber and dispersant are mixed and dispersed, a foam stabilizer is added and pre-stirred to obtain a foam slurry, which is extruded and dried to obtain a fiber preform.

[0025] Preferably, the application includes the following specific steps:

[0026] 3 to 6 parts by weight of high-performance inorganic fiber, 0.1 to 0.24 parts by weight of polyester fiber, and 0.02 to 0.06 parts by weight of dispersant are mixed and dispersed, and then the above-mentioned foam stabilizer is added. The mixture is pre-stirred at 800 to 1000 rpm for 2 to 5 minutes, and then stirred at 1400 to 2000 rpm for 15 to 20 minutes to obtain a foam slurry, which is extruded and dried to obtain a fiber preform.

[0027] Preferably, the high-performance inorganic fiber is at least one of quartz fiber, alumina fiber and glass fiber, and has a length of 3 to 36 mm.

[0028] Preferably, the dispersant is at least one of xanthan gum, guar gum, polyethylene oxide and hydroxypropyl methylcellulose.

[0029] A fiber preform is prepared by the above application.

[0030] Preferably, the fiber preform has a basis weight of 195 to 780 g / cm 2 .

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects

[0032] (1) The raw materials used in the foam stabilizer prepared by the present invention are environmentally friendly and pollution-free, and are green and environmentally friendly materials that meet the trend requirements of modern environmental protection.

[0033] (2) The bacterial cellulose in the foam stabilizer of the present invention exhibits a unique ribbon-like shape. It can be adsorbed over a large area on the surface of bubbles generated by the surfactant by means of electrostatic attraction, thereby strengthening the close arrangement between the surfactants and hindering the desorption of the surfactants. The bacterial cellulose has good water retention properties and can fill the gaps between the surfactants while also delaying the drainage of the liquid film. The interaction between the bacterial cellulose and the surfactant increases the stability of the foam.

[0034] (3) The high-performance inorganic fibers in the present invention have hydrophobic properties. The addition of surfactants and dispersants can improve the wettability of the inorganic fiber surface. While promoting fiber dispersion, it can also increase the contact points with bubbles, making them evenly dispersed in all parts of the foam. Bacterial cellulose directly adheres to the surface of the inorganic fibers. The presence of hydroxyl groups on the surface of the inorganic fibers creates hydrogen bonding forces between the inorganic fibers, enhancing the strength of the fiber preform. At the same time, the bacterial cellulose itself has an ultra-long crystal structure, which can also help improve the strength of the fiber preform. Compared with the case without the addition of the foam stabilizer, the tensile stress and maximum force of the fiber preform increased by 265.50-783.04% and 280.16-838.91%, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] (1)Figure 1 It is an intuitive diagram of the fiber preform;

[0036] (2) Figure 2 This is a diagram showing the effect of foam stabilizer on foam slurry half-life, foam air content and foam volume under different process conditions;

[0037] (3) Figure 3 This is a graph showing the effect of foam stabilizer on the comprehensive foam index of foam slurry under different process conditions;

[0038] (4) Figure 4 SEM images (a1-a3 are the surface morphologies of quartz fibers, b1-b3 are the morphologies of bacterial cellulose adhering to the surface of quartz fibers);

[0039] (5) Figure 5 is the tensile stress diagram;

[0040] (6) Figure 6 This is the maximum force diagram of the fiber preform before tearing. DETAILED DESCRIPTION

[0041] In order to further understand the present invention, the embodiments of the present invention will be further described in detail below with reference to examples and comparative examples. However, the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques can be used.

[0042] Example 1

[0043] (1) Add 6 parts by weight of dodecyldimethylamine oxide to 1000 parts by weight of tap water and stir for 10 minutes to obtain a dispersion.

[0044] (2) Add 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber and 0.06 parts by weight of polyethylene oxide into a debonding barrel. After debonding for 90 seconds, pour the mixture into a foaming barrel together with the dispersion liquid. Pre-stir with a stirrer at 1000 rpm for 2 minutes, and then stir at 1400 rpm for 15 minutes to obtain a quartz fiber foam slurry. Pour the quartz fiber foam slurry into a molding device (disclosed in CN114717870A patent) to obtain a wet fiber preform. Dry the preform in an oven for 2 hours to obtain a fiber preform with a weight of 195 g / m 2 .

[0045] Example 2

[0046] The bacterial cellulose dispersion was prepared as follows:

[0047] The bacterial cellulose was purified by treating the bacterial cellulose with a 1% NaOH solution for 20 minutes and then stirred at 20,000 rpm for 2 to 3 minutes to obtain a bacterial dispersion with a mass concentration of 0.8%. The bacterial cellulose had a diameter of 20 to 150 nm and a length of >20 μm. The preparation method of the bacterial cellulose dispersion used in the following examples was the same as that in this example.

[0048] (1) Preparation of a foam stabilizer: 12.5 parts by weight of a bacterial cellulose dispersion (concentration: 0.8 wt%) was added to 1000 parts by weight of tap water, stirred at 500 rpm for 5 min, and then 6 parts by weight of dodecyldimethylamine oxide was added, and stirring was continued for 10 min to obtain a foam stabilizer.

[0049] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber and 0.06 parts by weight of polyethylene oxide were added to a decomposition barrel. After decomposition for 90 seconds, the mixture was poured into a foaming barrel together with all the foam stabilizers. The agitator was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device (disclosed in CN114717870A) to obtain a wet fiber preform. The preform was dried in an oven for 2 hours to obtain a fiber preform with a weight of 195 g / m 2 .

[0050] Example 3

[0051] (1) Preparation of a foam stabilizer: 25 parts by weight of a bacterial cellulose dispersion (concentration: 0.8 wt.%) was added to 1000 parts by weight of tap water and stirred at 500 rpm for 5 min. 6 parts by weight of dodecyldimethylamine oxide was then added and stirred for 10 min to obtain a foam stabilizer.

[0052] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber and 0.06 parts by weight of polyethylene oxide were added to a decomposition barrel. After decomposition for 90 seconds, the mixture was poured into a foaming barrel together with all the foam stabilizers. The agitator was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device (disclosed in CN114717870A) to obtain a wet fiber preform. The preform was dried in an oven for 2 hours to obtain a fiber preform with a weight of 195 g / m 2 .

[0053] Example 4

[0054] (1) Preparation of a foam stabilizer: 37.5 parts by weight of a bacterial cellulose dispersion (concentration: 0.8 wt.%) was added to 1000 parts by weight of tap water and stirred at 500 rpm for 5 min. 6 parts by weight of dodecyldimethylamine oxide was then added and stirred for 10 min to obtain a foam stabilizer.

[0055] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber and 0.06 parts by weight of polyethylene oxide were added to a decomposition barrel. After decomposition for 90 seconds, the mixture was poured into a foaming barrel together with all the foam stabilizers. The agitator was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device (disclosed in CN114717870A) to obtain a wet fiber preform. The preform was dried in an oven for 2 hours to obtain a fiber preform with a weight of 195 g / m 2 .

[0056] Example 5

[0057] (1) Preparation of a foam stabilizer: 50 parts by weight of a bacterial cellulose dispersion (concentration: 0.8 wt.%) was added to 1000 parts by weight of tap water and stirred at 500 rpm for 5 min. 6 parts by weight of dodecyldimethylamine oxide was then added and stirred for 10 min to obtain a foam stabilizer.

[0058] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber and 0.06 parts by weight of polyethylene oxide were added to a decomposition barrel. After decomposition for 90 seconds, the mixture was poured into a foaming barrel together with all the foam stabilizers. The agitator was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device (disclosed in CN114717870A) to obtain a wet fiber preform. The preform was dried in an oven for 2 hours to obtain a fiber preform with a weight of 195 g / m 2 .

[0059] Test Example 1

[0060] The foam stability of the dispersion in step (1) of Example 1 and the foam stabilizer in step (1) of Examples 2 to 5 was tested: the dispersion or the foam stabilizer was stirred at 1400 rpm for 15 minutes to obtain a fiber-free foam slurry, and the foam stability thereof was tested using the Waring-Blender method. The results are shown below:

[0061] Figure 2The figure shows the effect of foam stabilizer on the half-life of foam slurry, foam air content and foam volume under different process conditions. As can be seen from the figure, in Example 1, the half-life of foam slurry is 116s, the foam air content is 65.07%, and the foam volume is 2945.27cm 3 In Example 2, the foam slurry half-life is 188s, the foam air content is 63.54%, and the foam volume is 2945.27cm 3 In Example 3, the foam slurry half-life is 216s, the foam air content is 63.60%, and the foam volume is 2932.41cm 3 In Example 4, the foam slurry half-life is 280s, the foam air content is 63.56%, and the foam volume is 2893.82cm 3 In Example 5, the foam slurry half-life is 316s, the foam air content is 61.99%, and the foam volume is 2842.38cm 3 .Depend on Figure 2 It can be seen that when only surfactant is added, the half-life is only 116 seconds, which is much shorter than the half-life of the foam generated by the synergistic action of bacterial cellulose and surfactant. The half-life increases with the increase in the amount of bacterial cellulose, demonstrating that the foam stabilizer can maintain a uniform and stable foam state and enhance foam stability. The foam air content and foam volume of the foam slurry decrease with the increase in the amount of foam stabilizer. This may be because the presence of bacterial cellulose increases the viscosity of the slurry, and the energy provided by stirring is insufficient to form a large number of bubbles in the slurry, resulting in a decrease in the foam air content and foam volume. Figure 3 is the comprehensive foam index diagram of the foaming agent under different process conditions, Figure 3 It can be seen that the comprehensive foam index increases with the increase of the amount of foam stabilizer. It can be seen that the foam stabilizer is greatly beneficial to foam stability and can effectively improve foam stability. This is consistent with the Figure 2 The analysis results are consistent.

[0062] Figure 4 The following are SEM images. a1-a3 show the surface morphology of quartz fibers. The surface of quartz fibers is smooth and free of obvious micropores, protrusions, or impurity accumulation, unlike the deep wrinkles on the surfaces of plant and organic fibers. b1-b3 show the morphology of bacterial cellulose adhered to the surface of quartz fibers. The bacterial cellulose is fibrillar, interlaced to form a fine network structure that firmly adheres to the surface of the quartz fibers. The presence of bacterial cellulose creates hydroxyl groups on the surface of the quartz fibers, resulting in strong hydrogen bonding between the fibers, which enhances the strength of the fiber preform.

[0063] Test Example 2

[0064] The mechanical properties of the fiber preforms prepared in Examples 1 to 5 were tested, specifically tensile stress test and tear resistance test, using an INSTRON 3300 series mechanical testing system. The test results were as follows:

[0065] Figure 5 The figure shows the tensile stress of the fiber preform under different process conditions. The greater the tensile stress, the better the tensile strength. As can be seen from the figure, when no foam stabilizer is added in Example 1, the tensile stress of the fiber preform is 0.9 MPa. After adding the foam stabilizer, the tensile stress of the fiber preform in Example 2 is 6.25 MPa, which is a 265.50% increase in tensile stress; the tensile stress of the fiber preform in Example 3 is 9.39 MPa, which is a 449.12% increase in tensile stress; the tensile stress of the fiber preform in Example 4 is 12.43 MPa, which is a 626.90% increase in tensile stress; and the tensile stress of the fiber preform in Example 5 is 15.10 MPa, which is a 783.04% increase in tensile stress. This shows that the addition of a foam stabilizer can help improve the tensile strength of the fiber preform.

[0066] Figure 6 The maximum force experienced by a fiber preform before tearing under different process conditions is shown in the figure. As can be seen from the figure, in Example 1, without the addition of a foam stabilizer, the maximum force experienced by the fiber preform is 1.15 N. With the addition of a foam stabilizer, the maximum force experienced by the fiber preform in Example 2 is 69.19 N, a 280.16% increase; in Example 3, the maximum force experienced by the fiber preform is 107.08 N, a 488.35% increase; in Example 4, the maximum force experienced by the fiber preform is 147.67 N, a 711.37% increase; and in Example 5, the maximum tensile force experienced by the fiber preform is 170.70 N, an 838.91% increase. This demonstrates that the addition of a foam stabilizer can help enhance the tear resistance of the fiber preform.

[0067] Comparative Example 1

[0068] (1) Preparation of a foam stabilizer: 5 parts by weight of silicon dioxide was added to 1000 parts by weight of tap water, stirred at 500 rpm for 5 minutes, and then 6 parts by weight of dodecyldimethylamine oxide was added, and stirring was continued for 10 minutes to obtain a foam stabilizer;

[0069] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber, and 0.06 parts by weight of polyethylene oxide were added to a degassing barrel. After degassing for 90 seconds, the mixture was poured into a foaming barrel together with a foam stabilizer. The mixture was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain a quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device to obtain a wet fiber preform. The fiber preform was dried in an oven for 2 hours to obtain a fiber preform. The tensile stress of the fiber preform was 1.07 MPa, and the maximum force it was subjected to was 1.36 N.

[0070] Comparative Example 2

[0071] (1) Preparation of a foam stabilizer: 0.2 parts by weight of cellulose nanofibers were added to 1000 parts by weight of tap water, stirred at 500 rpm for 5 minutes, and then 6 parts by weight of dodecyldimethylamine oxide were added, and stirring was continued for 10 minutes to obtain a foam stabilizer.

[0072] (2) Preparation of fiber preform: 3 parts by weight of quartz fiber, 0.24 parts by weight of polyester fiber, and 0.06 parts by weight of polyethylene oxide were added to a degassing barrel. After degassing for 90 seconds, the mixture was poured into a foaming barrel together with a foam stabilizer. The mixture was pre-stirred at 1000 rpm for 2 minutes and then stirred at 1400 rpm for 15 minutes to obtain a quartz fiber foam slurry. The quartz fiber foam slurry was poured into an extrusion molding device to obtain a wet fiber preform. The preform was dried in an oven for 2 hours to obtain a fiber preform. The tensile stress of the fiber preform was 4.80 MPa, and the maximum force it was subjected to was 7.00 N.

[0073] Table 1

[0074]

[0075] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A fiber preform, characterized in that: Including high-performance inorganic fiber, polyester fiber, dispersant and foam stabilizer; The foam stabilizer comprises the following components in parts by weight: 12.5-125 parts bacterial cellulose dispersion 1-10 parts surfactant 1000-2000 parts of water; The mass concentration of the bacterial cellulose dispersion is 0.5-1%.

2. The fiber preform according to claim 1, characterized in that The foam stabilizer comprises the following components in parts by weight: 12.5-50 parts bacterial cellulose dispersion 1 to 6 parts surfactant 1000 parts water.

3. The fiber preform according to claim 1 or 2, characterized in that: The bacterial cellulose dispersion is obtained by treating the bacterial cellulose with 1wt.% to 5wt.% NaOH solution and then dispersing it at high speed.

4. The fiber preform according to claim 1, characterized in that The surfactant is at least one of dodecyldimethylamine oxide, sodium dodecylbenzenesulfonate, and hexadecyltrimethylammonium bromide.

5. The fiber preform according to any one of claims 1 to 4, characterized in that: The preparation method of the foam stabilizer comprises the following steps: adding bacterial cellulose dispersion into water, stirring, adding surfactant, and continuing to stir until uniform.

6. A method for preparing a fiber preform according to claim 1, characterized in that: The steps include: After high-performance inorganic fiber, polyester fiber and dispersant are mixed and dispersed, a foam stabilizer is added and pre-stirred to obtain a foam slurry, which is extruded and dried to obtain a fiber preform.

7. The preparation method according to claim 6, characterized in that The specific steps include: 3 to 6 parts by weight of high-performance inorganic fiber, 0.1 to 0.24 parts by weight of polyester fiber, and 0.02 to 0.06 parts by weight of dispersant are mixed and dispersed, and then a foam stabilizer is added. The mixture is pre-stirred at 800 to 1000 rpm for 2 to 5 minutes, and then stirred at 1400 to 2000 rpm for 15 to 20 minutes to obtain a foam slurry. The foam slurry is extruded and dried to obtain a fiber preform.

8. The preparation method according to claim 7, characterized in that The high-performance inorganic fiber is at least one of quartz fiber, alumina fiber and glass fiber, and has a length of 3 to 36 mm; The dispersant is at least one of xanthan gum, guar gum, polyethylene oxide and hydroxypropyl methylcellulose.

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