Hydrophobic modified paper pulp fiber foam material and preparation method thereof
By preparing hydrophobically modified pulp fiber foam materials with a three-dimensional porous network structure, the problems of petroleum-based foams being difficult to degrade and deforming at high temperatures have been solved, and the hydrophobicity, thermal stability, and cushioning performance have been improved, making them suitable for packaging, construction, and medical fields.
Patent Information
- Application Number
- CN202511023092.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-11-11
AI Technical Summary
Existing petroleum-based foam materials are difficult to degrade naturally, resulting in white pollution. Traditional foam materials require additional coatings or modifications to achieve hydrophobic properties, and they are prone to softening and deformation under high-temperature environments. Some modifiers may release harmful substances, while plant fiber foam materials lack hydrophilicity and structural strength.
A three-dimensional porous network structure of hydrophobic modified pulp fiber foam material was prepared by using natural plant fiber pulp, sodium alginate, sodium dodecyl sulfate foaming agent and methyltrimethoxysilane hydrophobic modifier to form a silicon-oxygen bond hydrophobic layer through vapor deposition, combined with ultrasonic dispersion and foaming technology.
The material has excellent hydrophobic properties, good thermal stability and buffering properties, is suitable for high-temperature environments, and is biodegradable with no release of harmful substances, which simplifies the process and reduces costs.
Smart Images
Figure CN120925348A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of pulp fiber material technology, specifically relating to a hydrophobic modified pulp fiber foam material and its preparation method. Background Technology
[0002] Foam materials are widely used in packaging, building insulation, and medical fields due to their lightweight, porous structure, and excellent cushioning properties. However, current mainstream foam materials (such as petroleum-based plastic foams like polystyrene (EPS) and polyurethane (PU)) have many problems.
[0003] For example, petroleum-based foams are difficult to degrade naturally, and long-term accumulation leads to "white pollution," which violates the concept of sustainable development. Traditional foam materials usually require additional coatings or modifications to achieve hydrophobic properties, increasing process complexity and cost. Most plastic foams soften and deform easily at high temperatures (>100°C), limiting their application in high-temperature environments (such as electronic device packaging). Some blowing agents (such as chlorofluorocarbons) or modifiers may release harmful substances, threatening the ecological environment and human health.
[0004] Plant fibers have advantages such as being renewable, biodegradable, low-cost, and biocompatible, but their application still faces problems such as hydrophilicity defects, insufficient structural strength, and complex processing. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a hydrophobic modified pulp fiber foam material and its preparation method, thereby solving the aforementioned technical problems in the prior art.
[0006] The objective of this invention can be achieved through the following technical solutions:
[0007] A hydrophobically modified pulp fiber foam material comprises the following components in parts by weight:
[0008] Natural plant fiber pulp: 80-95 wt%;
[0009] Sodium alginate: 0.5-5 wt%;
[0010] Sodium dodecyl sulfate foaming agent: 0.1-2 wt%;
[0011] Methyltrimethoxysilane hydrophobic modifier: 1-10 wt%;
[0012] Wherein: the pulp fiber foam material has a three-dimensional porous network structure and a water contact angle ≥120°;
[0013] Thermal conductivity is 0.03-0.05 W / m·K;
[0014] The compressive modulus is 50-200 kPa, and the porosity is 80-95%.
[0015] Furthermore, the natural plant fiber pulp is selected from softwood pulp, bagasse pulp, bamboo pulp, agricultural waste fiber pulp, or a combination thereof.
[0016] Furthermore, a hydrophobic layer of silicon-oxygen bonds is formed on the surface of the pulp fiber foam material, and XPS detection shows that the characteristic peaks of the Si element are located at 102.3 eV and 103.6 eV.
[0017] Furthermore, the pulp fiber foam material contains 1-5 wt% nano-clay, 0.5-8 wt% silica, and 0.1-1.5 wt% carbon nanotubes.
[0018] The method for preparing the hydrophobically modified pulp fiber foam material includes the following steps:
[0019] S1. Dissolve sodium alginate in hot water at 80-90℃ to form a homogeneous solution;
[0020] S2. Disperse the natural plant fiber pulp into a suspension and mix it evenly with the sodium alginate solution;
[0021] S3. Add SDS foaming agent, stir at high speed (2000-4000 rpm) for 10-30 minutes.
[0022] S4. Inject the foam slurry into the mold, filter out the water initially, and then dry and shape it.
[0023] S5. The dried foam material is modified by vapor deposition with MTMS in a sealed environment.
[0024] Furthermore, in step S2, the pretreatment method for natural plant fiber pulp includes:
[0025] S201. Treat with 8-12% NaOH solution at 80℃ for 2 hours to remove hemicellulose;
[0026] S202, process the pulp to a freeness of 35-45°SR using a refiner to ensure fiber separation;
[0027] S203, treated with 30-45kHz ultrasound for 20-35 minutes, promotes fiber depolymerization.
[0028] Furthermore, in step S4, the drying temperature is 50-70℃ and the drying time is 6-10h.
[0029] Furthermore, in S5, the temperature for vapor deposition modification is 60-100℃, and the time is 1-5h.
[0030] Furthermore, it is used for cushioning packaging of electronic products, food, or fragile items.
[0031] The beneficial effects of this invention are:
[0032] 1. This invention modifies the fiber surface with methyltrimethoxysilane (MTMS) by vapor deposition, forming a stable Si-O-Si hydrophobic layer, resulting in a contact angle ≥128° and significantly improving water resistance. The modified foam material maintains a water droplet shape in the dripping test without penetration, making it suitable for humid environments or liquid packaging.
[0033] 2. The material formed by this invention has a high porosity of 80-95%, low density, but a compressive modulus of 50-200 kPa, which is superior to traditional paper-based foam. Its three-dimensional porous network structure (confirmed by SEM) provides excellent energy absorption capacity, making it suitable for cushioning packaging of electronic products, fragile items, etc.
[0034] 3. The material formed by this invention has a thermal conductivity of only 0.03-0.05 W / m·K, close to that of petroleum-based foam (such as EPS), and this conductivity is further reduced after hydrophobic modification (SF-MTMS has a thermal conductivity of 0.03892 W / m·K). In an 80℃ heating test, the material effectively insulates heat and maintains a stable surface temperature, making it suitable for thermal insulation packaging or building insulation applications.
[0035] 4. This invention uses natural plant fibers (such as bagasse pulp and bamboo pulp) as the main material, reducing dependence on petroleum resources. The material is biodegradable and produces no white pollution. The preparation process involves no strong acid / alkali treatment, avoiding fiber degradation and conforming to the principles of green chemistry.
[0036] 5. This invention adopts an integrated foaming-modification process, combining ultrasonic dispersion, vapor deposition and other technologies to simplify the traditional multi-step modification process. By optimizing the reaction temperature (60-100℃) and time (1-5h), the hydrophobic properties can be controlled and adjusted, making it suitable for industrial applications. Attached Figure Description
[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.
[0038] Figure 1 These are SEM images of the original slurry, foam samples with added sodium alginate, and foam samples after hydrophobic modification.
[0039] Figure 2 These are the Fourier transform infrared (FTIR) spectra of the materials before and after modification.
[0040] Figure 3 This is a comparison chart of the mechanical properties of SF and SF-MTMS samples.
[0041] Figure 4This is a comparison chart of individual performance of SF-MTMS samples. Detailed Implementation
[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0043] This invention provides a hydrophobically modified pulp fiber foam material, comprising the following components by weight:
[0044] Natural plant fiber pulp: 80-95 wt%; natural plant fiber pulp is selected from softwood pulp, bagasse pulp, bamboo pulp, agricultural waste fiber pulp or a combination thereof.
[0045] Sodium alginate: 0.5-5 wt%;
[0046] Sodium dodecyl sulfate foaming agent: 0.1-2 wt%;
[0047] Methyltrimethoxysilane hydrophobic modifier: 1-10 wt%;
[0048] Wherein: the pulp fiber foam material has a three-dimensional porous network structure and a water contact angle ≥120°;
[0049] The thermal conductivity is 0.03-0.05 W / m·K; it does not undergo significant deformation at a high temperature of 140℃.
[0050] The compressive modulus is 50-200 kPa, and the porosity is 80-95%.
[0051] A hydrophobic layer of silicon-oxygen bonds is formed on the surface of the pulp fiber foam material. XPS detection shows that the characteristic peaks of Si element are located at 102.3 eV and 103.6 eV.
[0052] Adding 1-5 wt% nano-clay, 0.5-8 wt% silica, and 0.1-1.5 wt% carbon nanotubes to pulp fiber foam materials can further improve their mechanical, electrical, or flame-retardant properties, thus meeting diverse needs.
[0053] A method for preparing hydrophobically modified pulp fiber foam material includes the following steps:
[0054] S1. Dissolve sodium alginate in hot water at 80-90℃ to form a homogeneous solution;
[0055] S2. Disperse the natural plant fiber pulp into a suspension and mix it evenly with the sodium alginate solution;
[0056] The pretreatment methods for natural plant fiber pulp include:
[0057] S201. Treat with 8-12% NaOH solution at 80℃ for 2 hours to remove hemicellulose;
[0058] S202, process the pulp to a freeness of 35-45°SR using a refiner to ensure fiber separation;
[0059] S203, treated with 30-45kHz ultrasound for 20-35 minutes, promotes fiber depolymerization.
[0060] S3. Add SDS foaming agent, stir at high speed (2000-4000 rpm) for 10-30 minutes.
[0061] S4. Inject the foam slurry into the mold, filter out the water initially, and then dry to form the shape; the drying temperature is 50-70℃, and the drying time is 6-10h.
[0062] S5. The dried foam material and MTMS are subjected to vapor deposition modification in a sealed environment. The temperature of vapor deposition modification is 60-100℃ and the time is 1-5h.
[0063] This product is used for cushioning packaging of electronic products, food, or fragile items.
[0064] The specific operating method is as follows: Dissolve 200 mL of distilled water in a beaker, add 0.9 g of sodium alginate, and place the beaker in an 80℃ water bath and stir until homogeneous. Then, weigh out 4 g of oven-dried bleached softwood pulp and 16 g of bagasse pulp separately and disperse them in a pulping machine to form a uniform pulp suspension. Pour the uniformly dissolved sodium alginate solution into the dispersed pulp suspension and continue stirring at 3000 rpm to ensure uniform mixing of the fiber and reagent. Add 0.8 g of SDS foaming agent to the mixed pulp solution, ensuring the total mass is 1000 g. Transfer the adjusted pulp suspension to the pulping machine and continue stirring at 3000 rpm to maintain a constant foam volume. Then, transfer the foam from the pulping machine to a polytetrafluoroethylene circular mold with a 40-mesh nylon mesh at the bottom for preliminary water filtration. Place the mold in a 60℃ oven to dry for 8 hours. After drying, remove the pulp foam material from the mold.
[0065] Figure 1The surface microstructure of the foam was characterized using scanning electron microscopy (SEM). As shown in the figure, whether it was foam prepared from the original slurry, foam with added sodium alginate, or foam modified with hydrophobicity, they all exhibited a three-dimensional porous network structure. (This provides a large surface area, which is beneficial for the transport and exchange of substances). Silanization modification of the foam made the originally hydrophilic material surface hydrophobic, and the modified foam material had a good contact angle of 128°. Hydrophobic modification not only changed the surface chemical properties of the foam but also affected its physical structure. According to the SEM images (10 μm scanning electron microscope images in Figures a, b, and c), the surface of the hydrophobically modified foam fibers became rougher. This increase in roughness may be due to the chemical reaction between silane molecules and hydroxyl groups on the fiber surface during vapor deposition, generating silicon-oxygen bonds and forming micro / nanoscale coatings or particles—i.e., MTMs—on the fiber surface. The coating formed on the fiber surface not only changed the surface wettability but also improved the overall stability of the material. Meanwhile, the hydrophobically modified fiber foam material exhibits an optimized layered structure, with clear boundaries between layers that are tightly connected by a stable fibrous network. This material displays a dense and uniformly distributed pore structure, with small and regular pores, resulting in a high porosity.
[0066] Figure 2 In the figure, (a) shows the infrared spectra of the original slurry, the foam sample after adding sodium alginate, and the foam sample after hydrophobic modification; (b) shows the XRD patterns of sodium alginate crystals and the foam sample after hydrophobic modification. The Fourier transform infrared (FTIR) spectroscopy analysis results of the materials before and after modification are presented. Specifically, at 3346 cm⁻¹... -1 The peak at 2933 cm⁻¹ is attributed to the stretching vibration of the -OH group; -1 and 1019cm -1 The absorption peak at 901 cm⁻¹ represents the symmetric stretching vibration of the CH bond. Furthermore, the silane introduced during the modification process leads to an absorption peak at 901 cm⁻¹. -1 and 1432cm -1 New peaks appear at 1607 cm⁻¹, corresponding to characteristic vibrations of Si-O-Si and Si-C chemical bonds, respectively. -1 The peak at 1631 cm⁻¹ indicates the formation of an acetal bond; this change originates from the peak originally located at 1631 cm⁻¹. -1 The transformation of the C=O stretching vibration peak at this point indicates that a polysiloxane reaction occurred between the pulp fibers and MTMS, which is beneficial for the pulp foam material to maintain its hydrophobic properties for a long time.
[0067] Contact angle test:
[0068] The experiment followed rigorous procedures for accurately evaluating the hydrophobic properties of hydrophobically modified pulp fiber foam using a KRUSS goniometer. A 0.4 μL water droplet was precisely controlled and dropped onto the sample surface using an automated syringe system. The contact angle value was calculated using contact angle meter software based on the droplet shape in the image. To ensure the reliability and representativeness of the results, the test was not limited to a single location for each sample; instead, five different points were randomly selected on the surface for repeated measurements. This step helps eliminate potential biases caused by minor inhomogeneities on the sample surface. The contact angle data from the five points were collected and averaged to obtain the comprehensive contact angle result of the hydrophobically modified pulp fiber foam, accurately reflecting its overall hydrophobic performance. A larger contact angle indicates a more hydrophobic material surface; conversely, a smaller contact angle indicates a more hydrophilic material.
[0069] Static compression test
[0070] Compression tests were conducted using the INSTRON 5565 multi-functional materials testing system, equipped with a specially designed dual compression plate and a 5kN load cell, ensuring the accuracy and applicability of the tests. Test samples were precisely cut into uniform cuboids with a 5mm x 5mm cross-section and a height of 30mm using a fine scalpel. They were then equilibrated for 24 hours under standard environmental conditions—23°C and 50% relative humidity—to eliminate any pre-existing stress and ensure consistent test conditions. Test parameters were carefully set: a compression rate of 5mm / min to apply pressure gradually and uniformly, avoiding interference from instantaneous impacts; the target final compression to 50% of the sample's original height, a proportion that effectively assesses the material's mechanical response under controlled deformation; and each sample underwent 10 cycles of compression to investigate the material's cyclic durability and plastic memory effect.
[0071] Chemical structure analysis
[0072] The chemical structure and surface element content of the foam were tested using X-ray photoelectron spectroscopy (XPS). The testing conditions were: operating at 75W power, using monochromatic AlKαX-ray (1486.6 eV) as the X-ray source, and recording two spectra: (1) full-spectrum spectrum; (2) high-resolution spectrum. The functional group structures of unmodified and MTMs-modified pulp fiber foams were analyzed by FTIR spectroscopy. The foam samples were mixed with KBr and pressed into thin sheets, with the structures measured at 98 to 106 cm⁻¹. -1 The analysis was performed with a spectral resolution of 1 cm⁻¹. -1The crystal structure and phase composition of the foam were tested using XRD. XRD is based on Bragg's Law, which states that when X-rays are incident on a crystal at a certain angle, they undergo coherent scattering with the atomic planes within the crystal. Diffraction occurs when the scattered waves satisfy a specific phase difference (usually an integer multiple of π). This specific angle (diffraction angle 2θ) has the following relationship with the X-ray wavelength (λ) and the interplanar spacing (d):
[0073] nλ=2dsin(θ)
[0074] XRD analysis results of the materials before and after modification. Specifically, typical cellulose diffraction peaks can be observed at 2θ = 14.5, 15.5° and 22.5°, corresponding to the -(110), (110) and (200) diffraction planes of cellulose I, respectively. This indicates that MTMS modification did not change the original crystal form of cellulose.
[0075] Hydrophobicity test:
[0076] Two identical (6cm x 6cm x 6cm) pieces of dry, unmodified pulp foam material and hydrophobically modified pulp foam material were placed in a 900ml beaker until the foam materials were allowed to settle. The hydrophobic effect of the samples was then observed.
[0077] When dyed water droplets (brown) are dropped onto unmodified pulp foam material, its surface properties are significantly improved.
[0078] Experiments have confirmed this: when water droplets land on the hydrophobically modified pulp foam material, they are not immediately absorbed by the material, but instead form distinct spherical shapes, which directly reflects the excellent hydrophobic properties of the modified material.
[0079] Specifically, the hydrophobic properties were quantitatively analyzed by measuring the contact angle between water droplets and the material surface. The results showed that the contact angle of the unmodified pulp foam material was 0°, indicating that it originally had hydrophilicity; while after modification, the contact angle increased significantly to 128°. This significant data change clearly demonstrates the successful hydrophobic modification treatment, which enhanced the waterproof performance of the material surface.
[0080] In the experiment, the experimental temperature was set at 90℃, and 5 mL of the modifier MTMS was added. Parallel gradient experiments were conducted at reaction times of 1 h, 2 h, 3 h, 4 h, and 5 h. The hydrophobic angles measured after heating for 1 h were 103.2°, after 2 h they were 119.9°, after 3 h they were 121.2°, after 4 h they were 122°, and after 5 h they were 128°. The data show that the contact angle of the modified pulp fiber foam material increases with the increase of reaction time. This phenomenon fully demonstrates that with the increase of experimental time, more MTMS is incorporated into the fiber foam material, and the bonding with the fiber foam material is better, resulting in a more hydrophobic layer formed on the surface.
[0081] In the experiment, the reaction time was set at 2 hours, 5 mL of the modifier MTMS was added, and parallel gradient experiments were conducted at reaction temperatures of 60℃, 70℃, 80℃, 90℃, and 100℃. The hydrophobic angles measured at 60℃ were 89.2°, 70℃ 109.8°, 80℃ 116.3°, 90℃ 119.9°, and 100℃ 122.9°. The data shows that the contact angle of the modified pulp fiber foam material increases with increasing temperature. This phenomenon indicates that with increasing experimental temperature, more MTMS is incorporated into the fiber foam material, resulting in better bonding and a more hydrophobic hydrophobic layer formed on the surface.
[0082] After modification with MTMs, the spectrum showed the addition of characteristic peaks for silicon (Si), indicating that the modified material had been embedded. Further analysis of the high-resolution Si spectrum of the hydrophobically treated foam revealed specific peaks at 102.3 eV and 103.6 eV, strongly suggesting that Si is stably present in this hydrophobic pulp foam system through Si-O chemical bonds. This finding directly confirms that the MTMS applied via vapor deposition successfully reacted with the hydroxyl groups in the pulp foam matrix, thus laying the foundation for the formation of an effective hydrophobic barrier. This modification strategy not only alters the surface chemistry of the foam but also potentially enhances its physical structure and functionality.
[0083] pass Figure 3 It can be seen that the compressive modulus of S-MTMS is worse than that of B, but after adding the modifier MTMS, the compressive modulus of S-MTMS is improved compared to that of B. In the compressive stress (σ)-strain (ε) ratio, the modified S-MTMS shows a slight improvement compared to B, but no significant change. This indicates that the compressive properties of the modified S-MTMS are slightly improved.
[0084] To test the thermal insulation performance of the foam, SF-MTMS foam was placed on a heating plate at 23.2°C. Figure 4As shown in Figure a (Figure a shows the thermal insulation of the SF-MTMS sample, and Figure b shows the thermal conductivity of the BF and SF-MTMS samples), the initial temperature of the foam surface was 23.2℃. After heating for 30 minutes, the temperature of the foam surface rose to 74.5℃. After 1 hour, the temperature of the foam stabilized at approximately 80℃, while the indoor temperature insulated by the foam remained below 30℃, indicating good thermal insulation performance. The thermal conductivity of the two foams, BF and SF-MTMS, was tested, as shown in Figure b. Figure 4 As shown in b, the thermal conductivity of BF and SF-MTMS foams are 0.04969 and 0.03892 W / mK, respectively. The thermal conductivity decreased after hydrophobic modification, indicating that the insulation performance of the foam was also enhanced.
[0085] To evaluate the thermal stability of pulp foam and plastic foam materials, we conducted a heat resistance test. The experimental procedure involved placing pulp foam samples and plastic foam samples of the same size together in ovens at 80℃, 100℃, 120℃, and 140℃ for 10 minutes each. The results showed that at 80℃ and 100℃, neither the pulp foam nor the plastic foam exhibited significant changes in morphology. However, when the temperature reached 120℃, the plastic foam showed a noticeable shrinkage in morphology. In contrast, the pulp foam material did not show significant morphological changes even at 140℃. This demonstrates that pulp fiber foam materials possess superior heat resistance compared to plastic foam materials. This result indicates that this cellulose pulp foam material is not only biodegradable but also possesses better heat resistance than traditional plastic foam, further illustrating its potential application as a high-performance sustainable material.
[0086] In summary, as shown in Table 1 below,
[0087] Table 1
[0088]
[0089] This invention achieves synergistic optimization of hydrophobicity, mechanical strength, thermal insulation and high-temperature stability through natural fiber substrate, vapor deposition hydrophobic modification and porous structure control, combining environmental protection and functionality, and has broad application prospects in packaging, construction, medical and other fields.
[0090] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.
Claims
1. A hydrophobically modified pulp fiber foam material, characterized in that, Composed of the following parts by weight: Natural plant fiber pulp: 80-95 wt%; Sodium alginate: 0.5-5 wt%; Sodium dodecyl sulfate foaming agent: 0.1-2 wt%; Methyltrimethoxysilane hydrophobic modifier: 1-10 wt%; Wherein: the pulp fiber foam material has a three-dimensional porous network structure and a water contact angle ≥120°; Thermal conductivity is 0.03-0.05 W / m·K; The compressive modulus is 50-200 kPa, and the porosity is 80-95%.
2. The hydrophobically modified pulp fiber foam material according to claim 1, characterized in that, The natural plant fiber pulp is selected from softwood pulp, bagasse pulp, bamboo pulp, agricultural waste fiber pulp, or a combination thereof.
3. The hydrophobically modified pulp fiber foam material according to claim 1, characterized in that, A hydrophobic layer of silicon-oxygen bonds is formed on the surface of the pulp fiber foam material. XPS detection shows that the characteristic peaks of the Si element are located at 102.3 eV and 103.6 eV.
4. The hydrophobically modified pulp fiber foam material according to claim 1, characterized in that, The pulp fiber foam material contains 1-5 wt% nano-clay, 0.5-8 wt% silica, and 0.1-1.5 wt% carbon nanotubes.
5. The method for preparing hydrophobically modified pulp fiber foam material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Dissolve sodium alginate in hot water at 80-90℃ to form a homogeneous solution; S2. Disperse the natural plant fiber pulp into a suspension and mix it evenly with the sodium alginate solution; S3. Add SDS foaming agent, stir at high speed (2000-4000 rpm) for 10-30 minutes. S4. Inject the foam slurry into the mold, filter out the water initially, and then dry and shape it. S5. The dried foam material is modified by vapor deposition with MTMS in a sealed environment.
6. The method for preparing hydrophobically modified pulp fiber foam material according to claim 5, characterized in that, In step S2, the pretreatment method for natural plant fiber pulp includes: S201. Treat with 8-12% NaOH solution at 80℃ for 2 hours to remove hemicellulose; S202, process the pulp to a freeness of 35-45°SR using a refiner to ensure fiber separation; S203, treated with 30-45kHz ultrasound for 20-35 minutes, promotes fiber depolymerization.
7. The method for preparing hydrophobically modified pulp fiber foam material according to claim 5, characterized in that, In step S4, the drying temperature is 50-70℃ and the drying time is 6-10h.
8. The method for preparing hydrophobically modified pulp fiber foam material according to claim 5, characterized in that, In step S5, the temperature for vapor deposition modification is 60-100℃, and the time is 1-5h.
9. The application of the hydrophobically modified pulp fiber foam material according to claim 1, characterized in that, Cushioning packaging for electronic products, food, or fragile items.