Biomass-based cellulose-based vitreous body-like material and preparation method thereof

Abstract

The invention belongs to the technical field of cellulose materials, and discloses a biomass-based cellulose-based vitreous body material and a preparation method thereof. According to the biomass-based cellulose-based vitreous body-like material, complete biomass cellulose fibers retaining a natural multilevel structure are used as a matrix, and a first network is constructed in the matrix and is a network formed by crosslinking biomass cellulose supramolecular fibers through dynamic covalent bonds, and a second network is constructed in the matrix and is a network formed by crosslinking biomass cellulose supramolecular fibers through dynamic covalent bonds; and the second network is a reinforcing network formed by penetration and crosslinking of a reinforcing agent in the first network. According to the method, renewable biomass such as vinasse and bamboo is directly used as raw materials, so that dependence on fossil resources is reduced, the method conforms to the sustainable development concept, and more importantly, high-added-value resource utilization of solid waste and the like in the wine brewing industry is realized. Meanwhile, the skeleton structure of the biomass natural fiber is fully utilized, so that the complex process of re-polymerization from small molecular monomers is avoided, and the use amount of chemical additives and the generation of byproducts are reduced from the source.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cellulose materials, in particular to a cellulose-based vitrimer material based on biomass and a preparation method thereof. BACKGROUND

[0002] Vitrimer materials, as a new type of polymer material, exhibit unique self-repairing, reworkability and reshaping properties due to the presence of dynamic covalent bonds, and have broad application prospects in the fields of flexible electronics, intelligent coatings and sustainable materials. Currently, the research and development of this type of material mainly follows two technical routes.

[0003] The first route is to directly use petroleum-based small molecule compounds as raw materials to construct a dynamic covalent network through polymerization and crosslinking reaction. However, petroleum is a non-renewable resource, and its overuse is contrary to the global goal of “carbon neutrality”. In addition, the preparation process usually involves complex synthesis steps, which requires the use of a large amount of chemicals, resulting in high energy consumption, high cost, and possibly producing environmentally unfriendly by-products.

[0004] In order to overcome the drawbacks of petroleum-based raw materials, researchers have proposed a second route, i.e. to use renewable biomass resources. In the prior art, a common approach is to select small molecule biomass derivatives such as vanillin and tannic acid as building blocks. Although the use of green raw materials is achieved, the extraction and purification process of these high-purity small molecules is complex, and the use of chemicals has not been fundamentally reduced. More importantly, due to the limited size of small molecules, the crosslinked network structure formed is usually loose, which makes it difficult to meet the requirements of high-performance applications in terms of mechanical strength and toughness, and the thermal stability is also poor.

[0005] On the other hand, plant biomass itself is rich in natural polymers with long chain structures and abundant functional groups (such as cellulose), which is considered to be an ideal skeleton for building high-strength materials. In theory, directly using these natural macromolecules can avoid the complex small molecule extraction process and fully utilize their inherent mechanical strength and thermal stability. However, the skilled person in the art has found in practice that due to the rigid structure of the biomass macromolecular chain and the inherent interchain entanglement, the chain segment movement ability is limited during processing, resulting in insufficient contact between the active sites of the macromolecules that can effectively form dynamic covalent crosslinks, and the overall mechanical properties (such as strength and toughness) of the prepared material are far from its theoretical potential, and the damage resistance is insufficient.

[0006] In view of this, the present application is proposed. SUMMARY

[0007] The present application aims to at least solve one of the above technical problems, and provides a cellulose-based vitrimer material based on biomass and a preparation method thereof.

[0008] To achieve the above object, the first technical solution of the present application is: The biomass-based cellulose-based vitrified material takes the intact biomass cellulose fiber retaining the natural multi-level structure as the matrix, and the matrix is constructed with: The first network is a network formed by the dynamic covalent cross-linking of the biomass cellulose supramolecular fiber; The second network is a reinforcing network formed by the penetration and cross-linking of the reinforcing agent in the first network.

[0009] Preferably, the biomass raw material includes at least one of vinasse, bamboo, straw, bagasse, wood, hemp and cotton.

[0010] Preferably, the dynamic covalent bond includes at least one of ester bond, borate ester bond, acylhydrazone bond, disulfide bond, Schiff base bond and imine bond.

[0011] Preferably, the reinforcing agent includes polyphenol and / or coordination metal ion.

[0012] Preferably, the polyphenol includes one or more of tannin, proanthocyanidin, condensed tannin, hydrolyzed tannin, tea polyphenol and mixed tannin, and the coordination metal ion includes one or more of copper ion, chromium ion, zinc ion, aluminum ion, magnesium ion, titanium ion and zirconium ion.

[0013] The second technical solution of the present application is: The preparation method of the biomass-based cellulose-based vitrified material includes: The biomass raw material is pretreated to activate the cellulose component and retain the natural multi-level structure at the same time; The pretreated biomass raw material is used to construct the first network through dynamic covalent cross-linking reaction; On the basis of the first network, the reinforcing agent is introduced to perform cross-linking reaction to construct the second network penetrating in the first network.

[0014] Preferably, the biomass raw material includes at least one of vinasse, bamboo, straw, bagasse, wood, hemp and cotton.

[0015] Preferably, the pretreatment includes at least one of alkali treatment, crushing, drying and activation; and the activation includes steam explosion, peroxide co-milling or TEMPO oxidation.

[0016] Preferably, the cellulose is modified before the first network is constructed, and the modification includes acetylation, esterification, hydrothermal activation or succinylation.

[0017] Preferably, the reinforcing agent comprises polyphenols and / or coordinating metal ions, added in solution form, and the amount added is, by mass percentage: 1%~10% polyphenols and 0.05%~4% coordinating metal ions; When the reinforcing agent is polyphenol and coordinating metal ions, the molar ratio of coordinating metal ions to polyphenols is 1:2~6.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention directly uses renewable biomass such as distiller's grains and bamboo as raw materials, which not only reduces dependence on fossil resources and aligns with the concept of sustainable development, but more importantly, it achieves high-value-added resource utilization of solid waste from the brewing industry. Simultaneously, by fully utilizing the skeletal structure of the biomass macromolecules themselves, it avoids the complex process of repolymerization from small molecule monomers, reducing the amount of chemical auxiliaries used and the generation of byproducts from the source, making the process more in line with green chemistry principles.

[0019] Unlike the traditional approach of "destroy first, then rebuild," the core technology of this invention lies in preserving and utilizing the natural multi-level structure of biomass cellulose. This natural structure, as a pre-formed, robust micro / nanofiber network, provides an ideal basic framework for the subsequent construction of dual networks, playing a natural reinforcing role. This not only simplifies the preparation process but also enables the final material to simultaneously possess the intrinsic properties of natural biomass and the intelligent properties of a glass-like structure.

[0020] This invention effectively overcomes the core problems of low crosslinking network density and poor uniformity caused by the rigidity and entanglement of biomass macromolecular chains by constructing a synergistic composite structure of a first network (dynamic covalent crosslinking network) and a second network (reinforcing network). The resulting glass-like material exhibits significantly improved tensile strength and thermal decomposition temperature, enabling its mechanical properties and thermal stability to meet the demands of a wider range of high-performance applications. Attached Figure Description

[0021] Figure 1 From left to right, the images are: SEM image of the pretreated distiller's grains powder obtained in Example 1, SEM image of the vitreous-like Vitrimer prepared in Example 1, and SEM image of the cross-section of the vitreous-like Vitrimer. Figure 2 Differential scanning calorimetry (DSC) curves of samples prepared in Example 1, Comparative Example 1, and Blank Example; Figure 3 Thermogravimetric curves of the samples prepared in Example 1, Comparative Example 1, and Blank Example. Detailed Implementation

[0022] 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.

[0023] The first embodiment of the present invention provides a biomass-based cellulose-based vitreous material, using intact biomass cellulose fibers that retain their natural multi-level structure as a matrix, wherein the matrix contains: The first network is a network formed by biomass cellulose supramolecular fibers cross-linked through dynamic covalent bonds; The second network is a reinforcing network formed by cross-linking the first network with a reinforcing agent.

[0024] This invention does not simply view biomass as a source of chemical components, but rather as a physical matrix with a naturally multi-level structure. The "complete biomass cellulose fibers retaining their natural multi-level structure" constitute the primary framework of the material. This framework itself possesses an inherent hydrogen bond network and microfiber structure, providing initial mechanical strength and thermal stability. Based on this, the construction of the first network involves dynamically covalently connecting the originally relatively independent cellulose supramolecular fibers into a unified whole, thereby endowing the material with macroscopic glass-like properties, such as self-healing and reprocessability. The introduction of the second network involves a reinforcing agent penetrating and undergoing secondary cross-linking within the formed first network, effectively increasing the cross-linking density and uniformity of the network. This solves the core problem of insufficient cross-linking sites and a loose network caused by the rigidity and high steric hindrance of the biomass macromolecular chains in a single dynamic network.

[0025] It can be seen that the second network is constructed after the first network. The first network, which is constructed first, forms a stable but still dynamic three-dimensional framework, providing a space and interface for the reinforcing agent of the second network to penetrate and anchor uniformly. If the order is reversed, the dense reinforcing network formed first will severely hinder the movement and approach of the biomass cellulose macromolecular chains, making it difficult for the dynamic covalent cross-linking reaction to proceed fully, resulting in the failure of the first network construction. The two networks have a clear division of labor in function and interpenetrate each other in structure. They work synergistically to improve the mechanical properties of biomass cellulose-based vitreous materials.

[0026] The biomass raw materials used in this invention include distiller's grains, bamboo, straw, bagasse, wood, hemp, and cotton, all of which are well-known in the art as typical cellulose-rich biomass raw materials. Their core components are all natural biomass fibers, possessing the aforementioned active sites such as hydroxyl groups that can be used to construct the network, as well as an inherent natural multi-level structure. The choice of biomass raw material is usually based on factors such as its wide availability, cost, cellulose content, and specific initial structure (e.g., the high density of bamboo, the high purity of cotton). These are all conventional choices that can be made by those skilled in the art based on common sense and do not affect the construction of the core dual-network structure of this invention or the realization of the final effect.

[0027] The dynamic covalent bonds mentioned above, including ester bonds, borate ester bonds, acylhydrazone bonds, disulfide bonds, Schiff base bonds, and imine bonds, are all well-studied and publicly reported types of dynamic covalent bonds suitable for constructing glass-like materials in the field of polymer science. These dynamic bonds have different bond energies, breakage / recombination rates, and responsiveness to stimuli. Those skilled in the art can routinely select one or more dynamic bonds to combine based on specific requirements such as the self-healing conditions, reprocessing temperature, and stability of the usage environment, using textbooks or existing technical materials; this is standard technical practice in the field.

[0028] In some preferred embodiments, the reinforcing agent is preferably polyphenol and / or coordinating metal ions, and the reinforcing network achieves reinforcement through various intermolecular forces. Specifically, the numerous phenolic hydroxyl groups in the polyphenol molecule can form dense hydrogen bonds with the ester groups, carbonyl groups, etc., in the cellulose backbone and its first network, and can also form π-π stacking interactions with other phenolic hydroxyl groups. This multiple physical cross-linking allows for reversible breakage and recombination when the material is subjected to external forces, effectively dissipating energy and thus improving the toughness and strength of the material. Metal ions can coordinate with the hydroxyl groups on the cellulose chain and the oxygen / nitrogen atoms in the dynamic covalent bonds to form stronger coordination bonds. This coordination network can significantly improve the modulus and hardness of the material. When both coexist, the coordinating metal ions can form a stable metal-phenol coordination network with the phenolic hydroxyl groups of the polyphenol. This network combines dynamism and high strength, interweaving and interpenetrating with the first network to form a more complex and robust composite network structure, thereby achieving the optimal reinforcing effect.

[0029] The selection of specific polyphenols or metal ions is based on conventional factors such as their reactivity, cost, color, or specific coordination ability. For example, tannic acid has a large number of phenolic hydroxyl groups, high cross-linking density, strong metal chelating ability, low cost, and easy availability; copper ions have high coordination cross-linking rates, dynamic reversibility, and low cost. These choices are obvious to those skilled in the art, and their reinforcing mechanisms are universal and do not depend on the unique structure of any particular molecule.

[0030] The second embodiment of the present invention provides a method for preparing a biomass-based cellulose-based vitreous material, comprising: Pre-treatment of biomass raw materials is carried out to activate their cellulose components while preserving their natural multilevel structure. Using pretreated biomass raw materials, a first network is constructed through a dynamic covalent cross-linking reaction; Based on the first network, a reinforcing agent is introduced to carry out a cross-linking reaction to construct a second network that permeates the first network.

[0031] Pretreatment of biomass raw materials is a well-established and publicly disclosed method in the art for processing biomass raw materials to extract or activate cellulose, including at least one of alkali treatment, pulverization, drying, and activation. Alkali treatment is mainly used to remove non-target components such as lignin and hemicellulose; pulverization and drying are routine pretreatment steps in material processing; steam explosion, peroxide co-grinding, and TEMPO oxidation are activation methods of varying intensities and principles, aiming to disrupt the hydrogen bond network of cellulose, exposing more reaction sites while preserving its macroscopic or microscopic natural structure as much as possible. The choice of which combination of pretreatment and activation is made depends on the type of raw material, the required purity of cellulose, the reactivity, and the tolerance for the degree of damage to the natural structure, all of which can be optimized by those skilled in the art through a limited number of routine experiments.

[0032] As examples, pulverization can be performed using conventional pulverizing equipment such as crushers, grinders, leather mills, and ball mills to pulverize biomass raw materials to a particle size of less than 300 mesh; steam explosion can be performed using an autoclave to treat biomass raw materials at a temperature of 121°C for 2 hours; peroxide co-grinding can be performed using a ball mill to grind biomass raw materials, placing biomass raw materials and sodium percarbonate in a ball mill jar at a mass ratio of 4:1, rotating at 300 rpm for 60 minutes; TEMPO oxidation can be performed by suspending biomass raw materials in deionized water containing TEMPO and NaBr, controlling the pH of the suspension at 10±0.1, adding NaClO solution dropwise into the system within 10 minutes, allowing for complete reaction, dialyzing, and then freeze-drying the sample to obtain TEMPO-oxidized cellulose.

[0033] In some preferred embodiments, the cellulose is modified before constructing the first network. These modifications include acetylation, esterification, hydrothermal activation, or succinylation. These modifications are standard chemical modification methods in the art for introducing specific functional groups onto the cellulose macromolecule to match the formation requirements of different dynamic covalent bonds (such as ester bonds, borate ester bonds, and acylhydrazone bonds). For example, to construct an ester bond network, cellulose is typically esterified to introduce ester groups; to construct a borate ester bond network, sufficient exposure and accessibility of hydroxyl groups must be ensured. The specific reaction conditions (such as temperature, time, and catalyst) for these modification methods are well described in the prior art, and their selection is directly related to the type of dynamic covalent bond to be constructed, falling under standard technical categories in the art.

[0034] For example, in the construction of a network based on dynamic ester bonds, the biomass cellulose is modified by esterification (e.g., phthalate esterification) to introduce ester groups onto its molecular chain. Subsequently, in the presence of a catalyst (e.g., anhydrous zinc acetate), it undergoes esterification or transesterification reactions with crosslinking agents such as polyacid anhydrides (e.g., succinic anhydride) or polyepoxides (e.g., bisphenol A diglycidyl ether) to form a dynamic ester bond crosslinking network.

[0035] When constructing a network based on dynamic borate ester bonds, the abundant hydroxyl groups of cellulose are exposed through physical activation (such as hydrothermal treatment) or chemical modification, allowing them to undergo esterification reactions with compounds containing borate groups (such as a complex pre-formed from 3,5-dihydroxybenzoic acid and boric acid) to form a dynamic borate ester bond crosslinking network.

[0036] When constructing a network based on dynamic acylhydrazone bonds, the biomass cellulose is acylated (e.g., succinylated) to introduce acyl groups onto its molecular chain, and then undergoes a condensation reaction with a hydrazine-containing crosslinking agent (e.g., adipic acid dihydrazide) to form a dynamic acylhydrazone bond crosslinking network.

[0037] The construction of the first network is typically carried out under heating conditions to facilitate the completion of the cross-linking reaction. Before constructing the first network, cellulose can be functionalized according to the type of dynamic covalent bond selected to provide the necessary reaction sites.

[0038] The dosage of reinforcing agents is determined through routine experiments to achieve an optimal range that effectively produces a synergistic reinforcing effect while avoiding excessive cross-linking that could lead to material embrittlement. For example, too low a polyphenol dosage will result in insignificant reinforcing effect, while too high a dosage may lead to uneven dispersion due to aggregation; excessive metal ions may cause excessively dense local cross-linking. Determining this effective range can be routinely done by those skilled in the art through a series of gradient experiments, using the material's mechanical strength, thermal stability, and other properties as indicators, without relying on any unconventional technical means.

[0039] In some preferred embodiments, the reinforcing agent comprises polyphenols and / or coordinating metal ions, added in solution form; when the reinforcing agent is polyphenols or coordinating metal ions, the amount added is, by mass percentage: 1%~10% polyphenols, 0.05%~4% coordinating metal ions; when the reinforcing agent is polyphenols and coordinating metal ions, the amount added is, by mass percentage: 1%~10% polyphenols, 0.05%~4% coordinating metal ions, and the molar ratio of metal to polyphenol is 1:2~6.

[0040] The following detailed description of biomass-based cellulose-based vitreous materials, their preparation methods, and properties is provided through several specific embodiments.

[0041] In the following examples, "parts" refers to "parts by weight".

[0042] Example 1: Ester bond network glass material (polyphenol reinforcement) Raw material pretreatment: Select distiller's grains, treat with alkali (4% NaOH, solid-liquid ratio 1:10, 110℃, 2h), then filter, wash, dry, and pulverize to below 300 mesh; Cellulose acetylation modification: 1 part of pretreated distiller's grains powder was mixed with 5 parts of glacial acetic acid / acetic anhydride in a volume ratio of 1:1, and then concentrated sulfuric acid was added as a catalyst. The mixture was reacted at 60°C for 4 hours. After the reaction solution was adjusted to neutral, water was added to precipitate the mixture, and the mixture was filtered. The precipitate was dried at 50°C. Cellulose esterification modification: The dried sample was mixed with 10 parts acetic acid, 0.074 parts phthalic anhydride and anhydrous sodium acetate catalyst, and reacted at 70 °C for 4 h; after adding water to precipitate, it was filtered and dried. First network construction and second network reinforcement: The dried product was mixed with succinic anhydride (SA), anhydrous zinc acetate (Zn(ac)2), and bisphenol A diglycidyl ether (DGEBA) at a mass ratio of 7:3:0.8:15.5 and reacted at 110℃ for 4 h; then a tannic acid solution (containing 0.1 parts of tannic acid) was added, and the reaction was continued at 110℃ for 1 h; finally, the system was cured at 160℃ for 6 h and allowed to stand at room temperature for 24 h to allow it to fully crosslink and form a network structure with self-healing and reversible crosslinking properties.

[0043] Example 2: Ester bond network glass material (metal ion reinforcement) Raw material pretreatment: Select distiller's grains, treat with alkali (4% NaOH, solid-liquid ratio 1:10, 110℃, 2h), then filter, wash, dry, and pulverize to below 300 mesh; Cellulose acetylation modification: 1 part of pretreated distiller's grains powder was mixed with 20 parts of glacial acetic acid / acetic anhydride in a volume ratio of 1:1, and then concentrated sulfuric acid was added as a catalyst. The mixture was reacted at 40°C for 6 hours. After centrifugation of the reaction solution, the supernatant was poured into water to precipitate, filtered, washed with water until neutral, and dried at 50°C. Cellulose esterification modification: Dissolve the dried sample in 10 parts of acetic acid, add 0.148 parts of phthalic anhydride and anhydrous sodium acetate catalyst, and react at 70℃ for 4 hours; after adding water to precipitate, filter, wash and dry. First network construction and second network reinforcement: The dried product was mixed with SA, Zn(ac)2 and DGEBA in a mass ratio of 7:3:0.8:15.5 and reacted at 110℃ for 4 h; then copper sulfate solution (containing 0.05 parts of copper ions) was added and the reaction was continued at 110℃ for 1 h; finally, the system was cured at 160℃ for 6 h and left to stand at room temperature for 24 h to allow it to fully crosslink and form a network structure with self-healing and reversible crosslinking properties.

[0044] Example 3: Ester bond network glass material (polyphenol-metal ion composite reinforcement) Raw material pretreatment: Select distiller's grains, treat with alkali (4% NaOH, solid-liquid ratio 1:10, 110℃, 2h), then filter, wash, dry, and pulverize to below 300 mesh; Cellulose acetylation modification: 1 part of pretreated distiller's grains powder was mixed with 10 parts of glacial acetic acid / acetic anhydride in a volume ratio of 1:1, and then concentrated sulfuric acid was added as a catalyst. The mixture was reacted at 40°C for 6 hours. After centrifugation of the reaction solution, the supernatant was poured into water to precipitate, filtered, washed with water until neutral, and dried at 50°C. Cellulose esterification modification: Dissolve the dried sample in 10 parts of acetic acid, add 0.1 parts of phthalic anhydride and anhydrous sodium acetate catalyst, and react at 70℃ for 4 hours; after adding water to precipitate, filter, wash and dry. First network construction and second network reinforcement: The dried product was mixed with SA, Zn(ac)2 and DGEBA in a mass ratio of 7:3:0.8:15.5 and reacted at 160℃ for 6 h; then copper sulfate solution (containing 0.05 parts copper ions) and tannic acid solution (containing 0.1 parts tannic acid) were added, and the reaction was continued at 110℃ for 1 h; finally, the system was cured at 160℃ for 6 h and allowed to stand at room temperature for 24 h to allow it to fully crosslink and form a network structure with self-healing and reversible crosslinking properties.

[0045] Example 4: Borate ester bond network glass material (metal ion reinforcement) Raw material pretreatment and hydrothermal activation: Select bamboo, after pretreatment, disperse 1 part bamboo fiber in 5 parts deionized water, and hydrothermally react at 120℃ for 30 min to obtain hydrothermally activated bamboo fiber suspension. First network construction: 3,5-dihydroxybenzoic acid (3,5-DHB) and boric acid (molar ratio 1:1) were dissolved in ethanol and allowed to stand at room temperature for 24 h to form a DHB-boric acid complex solution; 1 part of this solution was added to 3 parts of hydrothermally activated bamboo fiber suspension, and 0.0025 parts of p-toluenesulfonic acid was added as a catalyst, and the reaction was carried out at 80℃ for 2 h. Second network construction and molding: Add copper sulfate solution (containing 0.05 parts of copper ions) to the above system and continue the reaction at 80°C for 1 hour; then pour the product into a mold and let it stand at room temperature for 24 hours to solidify, and obtain a glass-like material.

[0046] Example 5: Borate ester bond network glass material (polyphenol reinforcement) Raw material pretreatment and hydrothermal activation: Select bamboo, after pretreatment, disperse 1 part bamboo fiber in 5 parts deionized water, and hydrothermally react at 120℃ for 30 min to obtain hydrothermally activated bamboo fiber suspension. First network construction: 3,5-dihydroxybenzoic acid (3,5-DHB) and boric acid (molar ratio 1:1) were dissolved in ethanol and allowed to stand at room temperature for 24 h to form a DHB-boric acid complex solution; 1 part of this solution was added to 3 parts of hydrothermally activated bamboo fiber suspension, and 0.0025 parts of p-toluenesulfonic acid was added as a catalyst, and the reaction was carried out at 80℃ for 2 h. Second network construction and molding: Add tannic acid solution (containing 0.1 parts of tannic acid) to the above system and continue to react at 80°C for 1 hour to allow the catechol groups of tannic acid to coordinate with the hydroxyl groups or borate ester bonds in cellulose; then pour the product into a mold and let it stand at room temperature for 24 hours to cure, and obtain a glass-like material.

[0047] Example 6: Borate ester bond network glass material (polyphenol-metal ion composite reinforcement) Raw material pretreatment and hydrothermal activation: Select bamboo, after pretreatment, disperse 1 part bamboo fiber in 5 parts deionized water, and hydrothermally react at 120℃ for 30 min to obtain hydrothermally activated bamboo fiber suspension. First network construction: 3,5-dihydroxybenzoic acid (3,5-DHB) and boric acid (molar ratio 1:1) were dissolved in ethanol and allowed to stand at room temperature for 24 h to form a DHB-boric acid complex solution; 1 part of this solution was added to 3 parts of hydrothermally activated bamboo fiber suspension, and 0.0025 parts of p-toluenesulfonic acid was added as a catalyst, and the reaction was carried out at 80℃ for 2 h. Second network construction and molding: Tannic acid solution (containing 0.1 parts tannic acid) and CuSO4 solution (containing 4 parts copper ions) were added to the above system, and the reaction was continued at 80°C for 1 hour; then the product was poured into a mold and allowed to stand at room temperature for 24 hours to solidify, thus obtaining a glass-like material.

[0048] Example 7: Acylhydrazone network glass material (polyphenol reinforcement) Raw material pretreatment and succinylation modification: Select distillers' grains, after pretreatment, mix 1 part of distillers' grain powder with 10 parts of DMF evenly, and heat to 80℃; add 0.0121 parts of succinic anhydride and 0.01 parts of tannic acid powder, and react at 80℃ for 4 hours under nitrogen protection with pyridine as catalyst; after reaction, cool in an ice-water bath, centrifuge, wash with water, and freeze dry to obtain modified distillers' grain powder; First network construction: Dissolve 1 part of the above modified distiller's grains powder in 10 parts of deionized water, add 10 parts of acylhydrazone crosslinking agent (adipic acid dihydrazide) and 0.025 parts of acetic acid catalyst, and react at 80°C for 2 hours to form a crosslinking system; Second network construction and molding: Add tannic acid solution (containing 0.1 parts of tannic acid) to the above crosslinking system, and continue to react at 80°C for 1 hour to allow the catechol groups of tannic acid to coordinate with the hydroxyl or hydrazone bonds in the wine lees powder; then pour the solution into a mold and let it stand at room temperature for 24 hours to solidify, and obtain a glass-like material.

[0049] Example 8: Acylhydrazone network glass material (metal ion reinforcement) Raw material pretreatment and succinylation modification: Select distillers' grains, after pretreatment, mix 1 part of distillers' grain powder with 20 parts of DMF evenly, and heat to 80℃; add 0.0153 parts of succinic anhydride, and react at 80℃ for 4 hours under nitrogen protection with pyridine as catalyst; after reaction, cool in an ice-water bath, centrifuge, wash with water, and freeze dry to obtain modified distillers' grain powder; First network construction and synchronous reinforcement: 1 part of modified distiller's grains powder was dissolved in 10 parts of deionized water, 10 parts of acylhydrazone crosslinking agent, 0.025 parts of acetic acid catalyst and copper sulfate solution (containing 0.05 parts of copper ions) were added, and the mixture was reacted at 80℃ for 2 hours; Second network strengthening and molding: Add copper sulfate solution (containing 0.05 parts of copper ions) to the system and continue the reaction at 80°C for 1 hour; then pour the solution into a mold and let it stand at room temperature for 24 hours to solidify, thus obtaining a glass-like material.

[0050] Example 9: Acylhydrazone network glass material (polyphenol-metal ion composite reinforcement) Raw material pretreatment and succinylation modification: Select distillers' grains, after pretreatment, mix 1 part of distillers' grain powder with 10 parts of DMF evenly, and heat to 80℃; add 0.045 parts of succinic anhydride, and react at 80℃ for 4 hours under nitrogen protection with pyridine as catalyst; after reaction, cool in an ice-water bath, centrifuge, wash with water, and freeze dry to obtain modified distillers' grain powder; First network construction and synchronous reinforcement: 1 part of modified distiller's grains powder was dissolved in 10 parts of deionized water, 10 parts of acylhydrazone crosslinking agent and 0.025 parts of acetic acid catalyst were added, and the reaction was carried out at 80℃ for 2 hours; Second network strengthening and molding: Tannic acid solution (containing 0.1 parts tannic acid) and CuSO4 solution (containing 0.05 parts copper ions) were added to the system, and the reaction was continued at 80°C for 1 hour; then the solution was poured into a mold and allowed to stand at room temperature for 24 hours to solidify, thus obtaining a glass-like material.

[0051] Example 10: Ester bond network glass material (polyphenol-metal ion composite reinforcement) Raw material pretreatment: Select distiller's grains, treat with alkali (4% NaOH, solid-liquid ratio 1:10, 110℃, 2h), then filter, wash, dry, and pulverize to below 300 mesh; Cellulose acetylation modification: 1 part of pretreated distiller's grains powder was mixed with 10 parts of glacial acetic acid / acetic anhydride in a volume ratio of 1:1, and then concentrated sulfuric acid was added as a catalyst. The mixture was reacted at 40°C for 6 hours. After centrifugation of the reaction solution, the supernatant was poured into water to precipitate, filtered, washed with water until neutral, and dried at 50°C. Cellulose esterification modification: Dissolve the dried sample in 10 parts of acetic acid, add 0.1 parts of phthalic anhydride and anhydrous sodium acetate catalyst, and react at 70℃ for 4 hours; after adding water to precipitate, filter, wash and dry. First network construction and second network reinforcement: The dried product was mixed with SA, Zn(ac)2 and DGEBA in a mass ratio of 7:3:0.8:15.5 and reacted at 160℃ for 6 hours; then zinc chloride and magnesium chloride solution (containing 2 parts zinc ions and 1 part magnesium ions) and polyphenol solution (containing 2 parts tea polyphenols and 3 parts ellagic acid) were added and reacted at 110℃ for 1 hour; finally, the system was cured at 160℃ for 6 hours and allowed to stand at room temperature for 24 hours to allow it to fully crosslink and form a network structure with self-healing and reversible crosslinking properties.

[0052] Comparative Example 1 Compared with Example 1, the only difference is that no tannic acid solution is added in the second network reinforcement step, that is, no reinforcement is performed, and the resulting material is only a material containing the first network structure.

[0053] Comparative Example 2 Compared with Example 4, the only difference is that copper sulfate solvent is not added in the second network construction and molding step, that is, no reinforcement is performed, and the resulting material is only a material containing the first network structure.

[0054] Comparative Example 3 Compared with Example 7, the only difference is that copper sulfate solvent is not added in the second network construction and molding step, that is, no reinforcement is performed, and the resulting material is only a material containing the first network structure.

[0055] Blank example The pretreated raw materials in Example 1: Distillers' grains were selected, treated with alkali (4% NaOH, solid-liquid ratio 1:10, 110℃, 2h), filtered, washed, dried, and crushed to below 300 mesh, and then molded at 2 MPa and room temperature.

[0056] The thermal decomposition temperature, glass transition temperature, and tensile strength of the materials prepared in the above examples, comparative examples, and blank examples were measured. The thermal decomposition temperature reflects the thermal stability of the material; a higher thermal decomposition temperature indicates better thermal stability. The glass transition temperature reflects the processability, or plasticity, of the material.

[0057] Thermal stability analysis method: The thermal stability of the material was determined by thermogravimetric analysis; the sample mass was 3~5mg, the test temperature range was room temperature to 500℃, the heating rate was 20℃ / min, and the nitrogen flow rate was 20mL / min. Differential scanning calorimetry method: The glass transition temperature of the material is determined by differential scanning calorimetry; the sample mass is 3~5mg, the temperature change rate is 10℃ / min, the nitrogen flow rate is 50.0mL / min, and the thermal history is eliminated by one thermal cycle; Tensile strength testing method: The glass-like raw materials obtained in the above examples and comparative examples require molding treatment during mechanical property testing to prepare specimens that meet the strength test requirements of GB / T 1040.2-2022. The tensile strength of the material is then determined using a universal mechanical testing system.

[0058] The measurement results are shown in Table 1. Figures 2-3 As shown.

[0059] Table 1. Performance Test Results of Glass-like Materials .

[0060] from Figure 2 As can be seen, compared with the blank example, Comparative Example 1 is a glass-like material after the first network is constructed, which has a significant glass transition temperature, indicating that the material has remodeling properties; Example 1 is a glass-like material after the second network is reinforced, and its glass transition temperature is significantly increased, indicating that the rigidity of the material is better after the second network is reinforced.

[0061] from Figure 3As can be seen, compared with the blank example, Comparative Example 1 is a glass-like material after the first network is constructed, and its thermal decomposition temperature is significantly increased, indicating good thermal stability. Example 1 is a glass-like material after the second network is reinforced, and its thermal decomposition temperature is significantly increased compared with the material after the first network is reinforced, indicating that the thermal stability of the material is greatly improved.

[0062] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A biomass-based cellulose-based vitreous material, characterized in that, Using intact biomass cellulose fibers that retain their natural multi-level structure as a matrix, the matrix contains: The first network is a network formed by biomass cellulose supramolecular fibers cross-linked through dynamic covalent bonds; The second network is a reinforcing network formed by cross-linking the first network with a reinforcing agent.

2. The biomass-based cellulose-based vitreous material as described in claim 1, characterized in that, Biomass raw materials include at least one of the following: distiller's grains, bamboo, straw, bagasse, wood, hemp, and cotton.

3. The biomass-based cellulose-based vitreous material as described in claim 1, characterized in that, The dynamic covalent bond includes at least one of the following: ester bond, borate ester bond, acylhydrazone bond, disulfide bond, Schiff base bond, and imine bond.

4. The biomass-based cellulose-based vitreous material as described in claim 1, characterized in that, The reinforcing agent includes polyphenols and / or coordinating metal ions.

5. The biomass-based cellulose-based vitreous material as described in claim 4, characterized in that, The polyphenols include one or more of tannic acid, proanthocyanidins, condensed tannins, hydrolyzed tannins, tea polyphenols, and mixed tannins; the coordinating metal ions include one or more of copper ions, chromium ions, zinc ions, aluminum ions, magnesium ions, titanium ions, and zirconium ions.

6. A method for preparing cellulose-based vitreous materials based on biomass, characterized in that, include: Pre-treatment of biomass raw materials is carried out to activate their cellulose components while preserving their natural multilevel structure. Using pretreated biomass raw materials, a first network is constructed through a dynamic covalent cross-linking reaction; Based on the first network, a reinforcing agent is introduced to carry out a cross-linking reaction to construct a second network that permeates the first network.

7. The method for preparing biomass-based cellulose-based vitreous materials as described in claim 6, characterized in that, Biomass raw materials include at least one of the following: distiller's grains, bamboo, straw, bagasse, wood, hemp, and cotton.

8. The method for preparing biomass-based cellulose-based vitreous materials as described in claim 6, characterized in that, The pretreatment includes at least one of alkali treatment, pulverization, drying, and activation; the activation includes steam explosion, peroxide co-grinding, or TEMPO oxidation.

9. The method for preparing biomass-based cellulose-based vitreous materials as described in claim 6, characterized in that, Before constructing the first network, the cellulose is modified, including acetylation, esterification, hydrothermal activation, or succinylation.

10. The method for preparing biomass-based cellulose-based vitreous materials as described in claim 6, characterized in that, The reinforcing agent comprises polyphenols and / or coordinating metal ions, added in solution form, with the following addition amount by mass percentage: 1%~10% polyphenols and 0.05%~4% coordinating metal ions; When the reinforcing agent is polyphenol and coordinating metal ions, the molar ratio of coordinating metal ions to polyphenols is 1:2~6.

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