A method for preparing bio-based materials based on rose fiber

Abstract

This application relates to the field of biomass material processing technology and discloses a method for preparing bio-based materials based on rose fibers. The method includes: mixing rose biomass powder, a reactive modifier system composed of choline chloride, anhydrous citric acid, and zinc acetate dihydrate, and deionized water to obtain a premix; subjecting the premix to a first-stage low-temperature thermal induction at 70-95°C to promote the chemical transformation of the epidermal stratum corneum; subsequently raising the temperature to 110-150°C for a second-stage high-temperature in-situ reaction to construct a metal coordination crosslinking network; and finally obtaining the product through cooling, pulverization, and hot pressing. This invention, through a graded temperature control process, utilizes in-situ generated fatty acid metal soaps for internal lubrication and metal ion coordination bonds for reinforcement, solving the problems of difficult processing, low strength, and poor water resistance of rose waste. The resulting material exhibits excellent thermoplastic processing properties, mechanical strength, and hydrophobicity.

Description

Technical Field

[0001] This invention relates to the field of biomass material processing technology, specifically a method for preparing bio-based materials based on rose fiber. Background Technology

[0002] The rose cultivation industry generates a large amount of waste stems annually, which are currently mainly disposed of through incineration or composting, resulting in low resource utilization rates. Converting this lignocellulosic waste into thermoplasticizable bio-based materials is an effective way to achieve high-value utilization. However, unlike conventional wood or bamboo, rose stems have a well-developed cuticle structure rich in cuticle and wax, exhibiting high density and chemical inertness.

[0003] In existing biomass plasticizing technologies, the presence of the rose epidermal cuticle has become a key factor restricting material performance. Due to the hydrophobicity and barrier effect of the cuticle, conventional chemical modifiers or plasticizers have difficulty penetrating into the fiber interior, leading to uneven reactions. If the epidermis is not removed before processing, the cuticle often forms interface defects in the matrix, severely affecting the material's mechanical strength and uniformity. However, removing the epidermis using pretreatment methods such as mechanical peeling or chemical leaching significantly increases process complexity and production costs, and generates additional wastewater treatment burdens.

[0004] Furthermore, conventional biomass material preparation techniques typically rely on adding small-molecule plasticizers such as glycerol and polyethylene glycol to achieve thermoplastic processing properties. While this physical blending method improves flowability, the small-molecule plasticizers are prone to migration within the matrix and cannot provide effective chemical cross-linking, resulting in materials with poor thermal stability and low mechanical strength. Moreover, due to the lack of effective sealing of numerous hydrophilic hydroxyl groups on the cellulose surface, the materials have high water absorption rates, making them unsuitable for use in humid and hot environments. Currently, there is no technical solution that can directly utilize all components of horny rose stems while simultaneously considering material processing rheology, mechanical strength, and water resistance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing bio-based materials based on rose fibers, which solves the problems in existing technologies such as poor processing flowability of rose biomass waste due to the presence of the epidermal cuticle, and the difficulty in simultaneously achieving mechanical strength and water resistance of biomass materials.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a technical solution for preparing bio-based materials based on rose fibers, using the following technical solution: A bio-based material prepared from rose fiber is made from raw materials comprising the following parts by weight: Rose biomass powder: 100 parts by weight; Reactive modifier system: 30-80 parts by weight; Deionized water: 0-4 parts by weight; The reactive modifier system consists of choline chloride, anhydrous citric acid, and zinc acetate dihydrate, wherein the molar ratio of choline chloride, anhydrous citric acid, and zinc acetate dihydrate is 1.0:(0.5-1.2):(0.05-0.30).

[0007] By adopting the above technical solution and utilizing the raw material ratio and the chemical interaction between components, a structure combining chemical cross-linking and physical lubrication is constructed within the material: Choline chloride and citric acid form a eutectic solvent framework, which utilizes its polarity and surface tension properties to disrupt the hydrogen bond network between cellulose molecules and plasticize the cell wall of rose biomass.

[0008] Zinc ions in the system act as coordination centers, forming coordination bonds with the carboxyl groups of citric acid molecules and the hydroxyl groups on cellulose molecular chains to construct a cellulose-citric acid-zinc coordination cross-linking network. This restricts the thermal motion of polymer chain segments and improves the mechanical strength and glass transition temperature of the material.

[0009] The zinc acetate in the raw material reacts in situ with the long-chain fatty acids produced by the hydrolysis of the rose epidermal stratum corneum. The resulting zinc fatty acid salts are dispersed at the matrix phase interface, playing an internal lubricating role and reducing the processing viscosity of the material.

[0010] Preferably, the rose biomass powder is made from the waste stems of the rose plant (Rosa chinensis), which are washed to remove mud and sand while retaining the cuticle layer of the epidermis, dried to a moisture content of less than 5%, and then pulverized to obtain powder with a particle size distribution between 60 mesh and 100 mesh.

[0011] By adopting the above technical solution, the utilization rate of biomass raw materials is improved by preserving the stratum corneum, and the long-chain fatty acid esters in the stratum corneum provide reaction substrates for the subsequent in-situ generation of lubricating components.

[0012] Preferably, the molar ratio of choline chloride, anhydrous citric acid, and zinc acetate dihydrate in the reactive modifier system is 1.0:(0.8-1.2):(0.15-0.30).

[0013] By adopting the above technical solution, the acid content and metal ion concentration within this range can balance the esterification reaction rate and coordination crosslinking density, avoiding cellulose degradation due to excessive acidity or agglomeration due to excessive metal content.

[0014] Preferably, the weight parts of each raw material are: 100 parts by weight of rose biomass powder, 50-70 parts by weight of reactive modifier system, and 2-3 parts by weight of deionized water.

[0015] By adopting the above technical solution, an appropriate amount of modifier ensures the coating and modification of the fiber, and an appropriate amount of moisture lowers the melting point of DES in the early stage of formation and promotes ion dissociation.

[0016] Preferably, the gel content of the bio-based material is 45%-78%, and the glass transition temperature (Tg) is 65-92℃; more preferably, the 24-hour water absorption rate of the bio-based material is less than 5%, and the melt mass flow rate (MFR) is 1.8-8.8 g / 10 min at 150℃ and a load of 2.16 kg.

[0017] By adopting the above technical solution, the gel content and Tg data indicate the formation of a chemical cross-linked network, and the water absorption rate and MFR data indicate that the material has both hydrophobicity and thermoplastic processability.

[0018] Secondly, this invention provides a method for preparing bio-based materials based on rose fibers, employing the following technical solution: A method for preparing bio-based materials based on rose fibers includes the following steps: Step S1, Material Premixing: The rose biomass powder, reactive modifier system and deionized water weighed according to the weight parts are mixed to obtain a premix; Step S2, First-level low-temperature thermal induction: The premix obtained in step S1 is sheared and kneaded at a temperature of 70-95℃ for 5-15 minutes. Step S3, Secondary High-Temperature In-Situ Reaction: The material treated in step S2 is heated to 110-150℃ and sheared and mixed for 10-30 minutes at this temperature to obtain a thermoplastic melt. Step S4, Molding Processing: The thermoplastic melt obtained in step S3 is cooled, pulverized, and then molded under hot pressing conditions to obtain the bio-based material.

[0019] By adopting the above technical solution, the graded temperature control process controls the progress of the chemical reaction. The specific mechanism is as follows: Penetration and dissociation (steps S1 and initial stage of step S2): Under the action of shear force and trace amounts of water, choline chloride, citric acid and zinc acetate form a molten fluid that wets the surface of rose powder and penetrates into the epidermis and amorphous cellulose region.

[0020] Keratinization and Lubricant Generation (Step S2, 70-95℃): In this temperature range, the acidic environment provided by citric acid promotes the hydrolysis of waxes and keratin polyesters in the stratum corneum of rose epidermis, releasing free long-chain fatty acids; the zinc ions dissociated in the system react with the long-chain fatty acids to form zinc fatty acid soaps in situ, reducing melt viscosity and improving the processing fluidity of keratin-containing raw materials.

[0021] Esterification grafting and coordination crosslinking (step S3, 110-150℃): The temperature rise initiates the esterification reaction between the carboxyl groups of citrate and the hydroxyl groups of cellulose, grafting the modifier molecules onto the fiber skeleton; at the same time, zinc ions act as nodes, forming coordination structures with unreacted carboxyl groups and cellulose hydroxyl groups, constructing a dual network of chemical crosslinking and physical coordination, thereby improving the mechanical strength and heat resistance of the material.

[0022] Hydrophobic shaping (later stages of steps S3 and S4): The high-temperature reaction consumes the hydrophilic hydroxyl groups on the surface of cellulose, and the metal coordination structure and hydrophobic fatty acid zinc soap reduce the exposure of polar groups, giving the material water resistance.

[0023] Preferably, in step S1, the reactive modifier system is prepared by mixing choline chloride, anhydrous citric acid and zinc acetate dihydrate in a certain proportion, mixing them in a high-speed mixer at a speed of 800-1000 rpm until a visually uniform white powder is formed, and then sealing and storing it in a dry container.

[0024] By adopting the above technical solution, homogeneous DES precursor powder is prepared by high-shear mixing, ensuring contact of each component at the microscale, while sealing and storing to prevent moisture absorption and inaccurate proportions.

[0025] Preferably, the specific process parameters for step S2 are: the internal mixer rotor speed is 30-60 rpm, the temperature is 80-90℃, and the time is 8-12 minutes.

[0026] By adopting the above technical solution, temperature and shear rate are controlled to ensure the penetration depth of the modifier, while avoiding the degradation of cellulose under acidic conditions.

[0027] Preferably, the specific process parameters for step S3 are: the internal mixer rotor speed is 60-100 rpm, the temperature is 130-140℃, and the time is 15-25 minutes.

[0028] By adopting the above technical solution, the energy required for the esterification reaction is provided by using higher temperature and shear rate, and the homogenization of high viscosity melt is promoted.

[0029] Preferably, in step S4, the temperature of the hot pressing conditions is 140-160℃, the pressure is 10-20MPa, and the holding time is 5-10 minutes.

[0030] By adopting the above technical solution, the internal pores of the material are eliminated under pressure, and the thermoplastic melt is cooled and solidified to obtain a dense sheet structure.

[0031] This invention provides a method for preparing bio-based materials based on rose fiber. It has the following beneficial effects: 1. This invention utilizes a primary low-temperature thermal induction process, employing acidic components and metal ions in a reactive modifier to in-situ convert the cuticle of rose stem epidermis into long-chain fatty acid metal salts. This conversion product acts as an internal lubricant, uniformly dispersed in the matrix, reducing melt viscosity, increasing the melt flow rate of the material, and solving the problem that cuticle-containing biomass raw materials are typically difficult to thermoplasticize.

[0032] 2. This invention utilizes a two-stage high-temperature in-situ reaction to construct a chemical cross-linking network with zinc ions as coordination centers. Under high-temperature shear, citric acid and cellulose undergo esterification, while zinc ions form stable coordination bonds with carboxyl and hydroxyl groups, restricting the thermal motion of molecular chain segments. This improves the tensile strength, gel content, and glass transition temperature of the material, thus mitigating the poor thermal stability of biomass materials.

[0033] 3. The bio-based material prepared by this invention has excellent hydrophobic properties. Through a chemical reaction, the hydrophilic hydroxyl groups on the surface of cellulose are consumed. Combined with the shielding effect of the in-situ generated hydrophobic metal soap and the metal coordination structure, the polarity of the material is reduced and water penetration is blocked, thus reducing the water absorption rate and improving the dimensional stability of the material in humid environments. Attached Figure Description

[0034] Figure 1 This is a flowchart of the preparation method of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0036] Please see the appendix Figure 1 This invention provides a method for preparing bio-based materials based on rose fibers, comprising: The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0037] Rose biomass powder is made from the waste stems of roses, a plant of the Rosaceae family. After removing the leaves and washing away the mud and sand, the cuticle of the epidermis is retained. The stems are dried at 60°C with forced air until the moisture content is less than 5%. The stems are then crushed by a pulverizer and sieved to select powder with a particle size distribution between 60 mesh and 100 mesh. Peeled rosewood powder is made from the same type of rose stems. After the outer skin is peeled off by manual or mechanical means to remove the cuticle, the remaining processing steps and specifications are the same as those for rose biomass powder. Choline chloride (CAS No.: 67-48-1, purity > 98%); anhydrous citric acid (CAS No.: 77-92-9, analytical grade); zinc acetate dihydrate (CAS No.: 5970-45-6, analytical grade); zinc stearate (CAS No.: 557-05-1, industrial grade); deionized water (CAS No.: 7732-18-5).

[0038] Preparation Example 1: This preparation example provides a reactive modifier system A1, comprising the following steps: Choline chloride, anhydrous citric acid, and zinc acetate dihydrate were weighed in a molar ratio of 1.0:0.8:0.15. The weighed components were placed in a high-speed mixer and mixed at 800 rpm for 10 minutes until a visually uniform white powder was obtained. The powder was then immediately sealed and packaged in a dry container to obtain the reactive modifier system A1.

[0039] Preparation Example 2: This preparation example provides a reactive modifier system A2, focusing on a low acidity and low metal content ratio, including the following steps: Choline chloride, anhydrous citric acid, and zinc acetate dihydrate were weighed in a molar ratio of 1.0:0.5:0.05. The weighed components were placed in a high-speed mixer and mixed at 800 rpm for 10 minutes until a visually uniform white powder was obtained. The powder was then immediately sealed and packaged in a dry container to obtain reactive modifier system A2.

[0040] Preparation Example 3: This preparation example provides a reactive modifier system A3, focusing on a ratio of high acidity and high metal content, including the following steps: Choline chloride, anhydrous citric acid, and zinc acetate dihydrate were weighed in a molar ratio of 1.0:1.2:0.30. The weighed components were placed in a high-speed mixer and mixed at 800 rpm for 10 minutes until a visually uniform white powder was obtained. The powder was then immediately sealed and packaged in a dry container to obtain reactive modifier system A3.

[0041] Preparation Example 4: This preparation example provides a comparative modifier system D1, which does not contain metal components, for subsequent verification of comparative examples, including the following steps: Choline chloride and anhydrous citric acid were weighed at a molar ratio of 1.0:0.8, without adding zinc acetate dihydrate. The weighed components were placed in a high-speed mixer and mixed at 800 rpm for 10 minutes until a visually uniform white powder was obtained. The powder was then immediately sealed and packaged in a dry container to obtain the comparative modifier system D1.

[0042] Example 1: This embodiment provides a method for preparing bio-based materials based on rose fibers, using the reactive modifier system A1 obtained in Preparation Example 1, specifically including the following steps: Step (1) Material premixing: Weigh 100g of rose biomass powder, 50g of reactive modifier system A1 and 2g of deionized water; place the above components in a high-speed mixer and mix at 1000rpm for 5 minutes to obtain a uniformly wetted solid premix.

[0043] Step (2) First-stage low-temperature thermal induction: Add the premix obtained in step (1) into the internal mixer, set the first stage temperature of the internal mixer to 85°C and the rotor speed to 40 rpm, and maintain the mixing at this temperature for 10 minutes to allow the modifier system to initially melt and induce the chemical transformation of the rose epidermal stratum corneum.

[0044] Step (3) Secondary high-temperature in-situ reaction: Raise the temperature of the internal mixer to 130°C, adjust the rotor speed to 80 rpm, and continue mixing at this temperature for 20 minutes to allow the material to undergo deep plasticization and in-situ coordination crosslinking reaction, and obtain a dark brown thermoplastic melt.

[0045] Step (4) Molding process: Take out the melt obtained in step (3), cool it naturally and then crush it; take an appropriate amount of crushed material and place it in the mold of the flat vulcanizing machine, press it for 5 minutes at 150℃ and 15MPa pressure, and then demold it to obtain the rose biomass material sheet.

[0046] Example 2: This embodiment provides a method for preparing bio-based materials based on rose fibers. The reactive modifier system A2 obtained in Preparation Example 2 is used to verify the lower limit of the process parameter range. The specific steps include: Step (1) Material premixing: Weigh 100g of rose biomass powder and 30g of reactive modifier system A2; place the above components in a high-speed mixer and mix at 1000rpm for 5 minutes to obtain a solid premix (in this embodiment, no deionized water was added, and the water content of the biomass itself was used to initiate the process).

[0047] Step (2) First-stage low-temperature thermal induction: Add the premix obtained in step (1) into the internal mixer, set the first stage temperature of the internal mixer to 70°C and the rotor speed to 30 rpm, and maintain the mixing at this temperature for 5 minutes to carry out the preliminary thermal induction treatment.

[0048] Step (3) Secondary high-temperature in-situ reaction: Raise the temperature of the internal mixer to 110°C, adjust the rotor speed to 60 rpm, and continue mixing at this temperature for 10 minutes to complete the plasticizing and modification process.

[0049] Step (4) Molding process: Take out the melt obtained in step (3), cool it naturally and then crush it; take an appropriate amount of crushed material and place it in the mold of the flat vulcanizing machine, press it at 140℃ and 10MPa pressure for 10 minutes, and after cold pressing and demolding, the rose biomass material sheet is obtained.

[0050] Example 3: This embodiment provides a method for preparing bio-based materials based on rose fibers. The reactive modifier system A3 obtained in Preparation Example 3 is used to verify the upper limit of the process parameter range. The method specifically includes the following steps: Step (1) Material premixing: Weigh 100g of rose biomass powder, 80g of reactive modifier system A3 and 4g of deionized water; place the above components in a high-speed mixer and mix at 1000rpm for 5 minutes to obtain a premix.

[0051] Step (2) First-stage low-temperature thermal induction: Add the premix obtained in step (1) into the internal mixer, set the first stage temperature of the internal mixer to 95°C and the rotor speed to 60 rpm, and maintain the mixing at this temperature for 15 minutes.

[0052] Step (3) Secondary high-temperature in-situ reaction: Raise the temperature of the internal mixer to 150°C, adjust the rotor speed to 100 rpm, and continue mixing at this temperature for 30 minutes to ensure that the high content of modifier reacts and crosslinks fully.

[0053] Step (4) Molding process: Take out the melt obtained in step (3), cool it naturally and then crush it; take an appropriate amount of crushed material and place it in the mold of the flat vulcanizing machine, press it at 160℃ and 20MPa pressure for 5 minutes, and then press it cold to demold to obtain the rose biomass material sheet.

[0054] Example 4: This embodiment provides a method for preparing bio-based materials based on rose fiber, using the reactive modifier system A1 obtained in Preparation Example 1, and changing the raw material ratio, specifically including the following steps: Step (1) Material premixing: Weigh 100g of rose biomass powder, 70g of reactive modifier system A1 and 3g of deionized water; place the above components in a high-speed mixer and mix at 1000rpm for 5 minutes.

[0055] Step (2) First-stage low-temperature thermal induction: Add the premix obtained in step (1) into the internal mixer, set the first stage temperature of the internal mixer to 80°C and the rotor speed to 40 rpm, and maintain the mixing at this temperature for 12 minutes.

[0056] Step (3) Secondary high-temperature in-situ reaction: Raise the temperature of the internal mixer to 135°C, adjust the rotor speed to 80 rpm, and continue mixing at this temperature for 15 minutes.

[0057] Step (4) Molding process: Take out the melt obtained in step (3), cool it naturally and then crush it; take an appropriate amount of crushed material and place it in the mold of the flat vulcanizing machine, press it for 5 minutes at 150℃ and 15MPa pressure, and then demold it to obtain the rose biomass material sheet.

[0058] Comparative Example 1: This comparative example is used to verify the key role of "primary low-temperature treatment" in the graded thermal induction process on keratin conversion and material properties.

[0059] Compared with Example 1, the difference is that the "first-level low-temperature thermal induction" process in step (2) is omitted; the premix obtained in step (1) is directly added to a mixer that has been preheated to 130°C and continuously mixed at 80 rpm for 30 minutes. The remaining operation steps and parameters are the same as in Example 1.

[0060] Comparative Example 2: This comparative example is used to verify the necessity of the "metal ion component" in the reactive modifier for constructing a dual network and in-situ saponification.

[0061] Compared with Example 1, the difference is that the reactive modifier system used in step (1) is replaced with an equal mass of "comparative modifier system D1" (i.e. the one obtained in Preparation Example 4, which does not contain zinc acetate dihydrate), and the other operation steps and parameters are the same as in Example 1.

[0062] Comparative Example 3: This comparative example is used to verify the difference in technical effects between "in-situ generation of metal soap" and "physical addition of lubricant".

[0063] Compared with Example 1, the difference is that the reactive modifier system used in step (1) is replaced with an equal mass of "comparative modifier system D1" (without zinc acetate dihydrate), and an additional 3.0g of commercially available "zinc stearate" powder is added to participate in the mixing. The remaining operation steps and parameters are the same as in Example 1.

[0064] Comparative Example 4: This comparative example is used to verify the applicability of preserving the epidermal stratum corneum to the specific process route of the present invention and the technical effect of "turning waste into treasure".

[0065] Compared with Example 1, the difference is that the raw material used in step (1) is replaced with an equal mass of "peeled rosewood powder" (i.e., removing the epidermal stratum corneum), and the remaining operation steps and parameters are the same as in Example 1.

[0066] Test Example 1: Testing of Processing Rheological and Physical-Mechanical Properties 1. Testing Method The bio-based material samples prepared in Examples 1-4 and Comparative Examples 1-4 were selected for performance characterization. Melt flow rate (MFR) was tested according to GB / T3682.1-2018 standard, with the temperature set at 150℃ and a nominal load of 2.16 kg. The mass of melt flowing out every 10 minutes was recorded from the dried sample after pelletizing. Mechanical properties were tested according to GB / T1040.1-2018 standard. The hot-pressed sheet was cut into type 5 dumbbell-shaped strips, and stretched using a universal testing machine at a rate of 50 mm / min. Tensile strength and elongation at break were recorded, and the arithmetic mean of 5 parallel samples was taken from each group. Water absorption was tested according to GB / T1034-2008 standard. The sample was cut into 50 mm × 50 mm × 2 mm square pieces, dried to constant weight at 60℃, and then immersed in deionized water at 23℃ for 24 hours. The mass change rate after water absorption was measured.

[0067] 2. Test Results The specific test data for each group of samples are shown in Table 1. Table 1 Summary of performance test data for examples and comparative samples

[0068] 3. Results Analysis and Conclusions The melt flow rate of Example 1 was 4.25 g / 10 min, while that of Comparative Example 1 was 0.32 g / 10 min. Both had the same formulation, the difference being that Comparative Example 1 omitted the low-temperature thermal induction step. Data showed that the low-temperature stage promoted the depolymerization and reaction of the rose epidermal stratum corneum, and the resulting product acted as an internal lubricant. Comparative Example 1 used a high-temperature one-step method, where citric acid preferentially reacted with cellulose, failing to effectively transform the stratum corneum, resulting in high melt viscosity and poor flowability. Comparative Example 4, which removed the stratum corneum-containing epidermis, had a flowability of 0.85 g / 10 min, lower than Example 1, confirming that chemical modification of the stratum corneum component in the raw material improved the processing rheology of the material.

[0069] The tensile strength of Example 1 was 28.7 MPa, while that of Comparative Example 2 was 11.4 MPa. Comparative Example 2 did not contain metal ions and therefore could not form a metal-coordinated crosslinking network; its structure was maintained solely by hydrogen and ester bonds, resulting in lower strength. Although Comparative Example 4 achieved a tensile strength of 31.2 MPa, its elongation at break was only 4.2%, exhibiting brittle fracture. This was due to the increased cellulose content after removing the epidermis, which increased the material's rigidity but resulted in insufficient toughness. Example 1 achieved an elongation at break of 18.4%, demonstrating that the introduction of metal coordination bonds improved strength while maintaining toughness.

[0070] The water absorption rate of Example 1 was 2.4%, while the water absorption rates of Comparative Examples 2 and 4 were 14.2% and 11.5%, respectively. The introduction of metal ions blocked the hydrophilic groups, and the derivatives generated by the transformation of the cuticle blocked the penetration of water molecules. Comparative Example 3, with the physical addition of zinc stearate, had a melt flow rate of 5.12 g / 10 min, but its tensile strength was only 17.8 MPa, and its water absorption rate was 6.8%. The physically added hydrophobic agent had weak interfacial bonding with the matrix, resulting in decreased strength and a less effective water-blocking effect than the in-situ reaction. The structure generated by the in-situ reaction in Example 1 was uniformly distributed at the phase interface, improving the hydrophobicity and mechanical properties of the material.

[0071] Test Example 2: Thermal Stability and Dynamic Thermomechanical Properties Test 1. Experimental Procedure Bio-based material samples prepared in Examples 1-4 and Comparative Examples 1-4 were selected. Thermal stability was tested using a thermogravimetric analyzer (TGA). 5-10 mg of dried sample was weighed and placed in an alumina crucible, heated from 30°C to 600°C at a heating rate of 10°C / min under a nitrogen atmosphere. The temperature at which 5% mass loss occurred (T5%) and the temperature corresponding to the maximum rate of thermal weight loss (Tmax) were recorded. Dynamic thermomechanical properties (DMA) were tested using a dynamic thermomechanical analyzer in single cantilever beam mode, with a frequency set to 1 Hz, a heating rate of 3°C / min, and a temperature range of -20°C to 150°C. The storage modulus (E') and the glass transition temperature (Tg) corresponding to the peak value of the loss factor (Tanδ) were measured. The degree of crosslinking was determined by solvent extraction to determine the gel content. The sample powder was wrapped in filter paper and extracted with anhydrous ethanol using a Soxhlet extractor for 24 hours. After drying, the percentage of the remaining mass relative to the initial mass was calculated.

[0072] 2. Test Results Table 2. Thermal and microstructural performance data of the examples and comparative samples.

[0073] 3. Conclusion The T5% of Example 1 was 248.3℃, and the Tmax was 352.1℃; the T5% of Comparative Example 2 was 205.1℃, and the Tmax was 315.6℃. In Comparative Example 2, no metal salt was added, and the free citric acid underwent dehydration and decomposition at high temperatures, resulting in low thermal stability of the material. In Example 1, zinc ions formed a coordination structure with citric acid and cellulose hydroxyl groups, and the in-situ generated metal soap improved the heat resistance of the matrix and inhibited the volatilization and degradation of low-molecular-weight components.

[0074] The glass transition temperature (Tg) of Example 1 was 88.4℃, and the gel content was 72.3%; the Tg of Comparative Example 2 was 52.8℃, and the gel content was 12.4%. The difference in Tg and gel content stems from the different network structures. Example 1 constructed a chemically cross-linked network through a high-temperature in-situ reaction, with metal ions acting as coordination centers to restrict the thermal motion of molecular chain segments. Comparative Example 2 mainly relied on hydrogen bonding, lacking chemical cross-linking points, resulting in a low residual mass after solvent extraction.

[0075] Comparative Example 3, with the physical addition of zinc stearate, had a Tg of 58.5°C and a gel content of 24.6%. The physically added metal soap only provided lubrication and did not participate in the chemical cross-linking between molecular chains; the zinc salt existed in a free state and could not restrict the movement of polymer chain segments. Example 4, with a higher modifier content, saw the storage modulus decrease to 1340 MPa and the Tg decrease to 65.7°C; the excess unreacted small molecules produced a plasticizing effect.

[0076] Comparative Example 1 omitted the first-stage low-temperature thermal induction, and its gel content was 32.1%, lower than that of Example 1. The staged temperature control process ensured an orderly reaction; the low-temperature stage promoted the penetration of the modifier and the transformation of the stratum corneum, providing conditions for the formation of a uniform cross-linked network in the high-temperature stage. Direct high-temperature mixing resulted in the reaction being confined to the particle surface, with a low degree of internal cross-linking.

[0077] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing bio-based materials based on rose fiber, characterized in that, It is prepared from raw materials comprising the following parts by weight: Rose biomass powder: 100 parts by weight; Reactive modifier system: 30-80 parts by weight; Deionized water: 0-4 parts by weight; The reactive modifier system consists of choline chloride, anhydrous citric acid, and zinc acetate dihydrate, wherein the molar ratio of choline chloride, anhydrous citric acid, and zinc acetate dihydrate is 1.0:0.5-1.2:0.05-0.

30.

2. The method for preparing bio-based materials based on rose fiber according to claim 1, characterized in that, The rose biomass powder is made from the waste stems of the rose plant (Rosa chinensis), which are washed to remove mud and sand while retaining the cuticle layer of the epidermis. The stems are dried until the moisture content is less than 5%, then pulverized and selected to obtain powder with a particle size distribution between 60 mesh and 100 mesh.

3. The method for preparing bio-based materials based on rose fiber according to claim 1, characterized in that, The molar ratio of choline chloride, anhydrous citric acid, and zinc acetate dihydrate in the reactive modifier system is 1.0:0.8-1.2:0.15-0.

30.

4. The method for preparing bio-based materials based on rose fiber according to claim 1, characterized in that, The weight parts of each raw material are as follows: Rose biomass powder: 100 parts by weight; Reactive modifier system: 50-70 parts by weight; Deionized water: 2-3 parts by weight.

5. The method for preparing bio-based materials based on rose fiber according to claim 1, characterized in that, The bio-based material has a gel content of 45%-78% and a glass transition temperature (Tg) of 65-92℃. The bio-based material has a 24-hour water absorption rate of less than 5%, and a melt mass flow rate (MFR) of 1.8-8.8 g / 10 min at 150 °C and a load of 2.16 kg.

6. A method for preparing bio-based materials based on rose fiber according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1, Material Premixing: The rose biomass powder, reactive modifier system and deionized water weighed according to the weight parts are mixed to obtain a premix; Step S2, First-level low-temperature thermal induction: The premix obtained in step S1 is sheared and mixed in an internal mixer at a temperature of 70-95℃ for 5-15 minutes. Step S3, Secondary High-Temperature In-Situ Reaction: The material treated in step S2 is heated to 110-150℃ and sheared and mixed for 10-30 minutes at this temperature to obtain a thermoplastic melt. Step S4, Molding Processing: The thermoplastic melt obtained in step S3 is cooled, pulverized, and then molded under hot pressing conditions to obtain the bio-based material.

7. The method for preparing bio-based materials based on rose fiber according to claim 6, characterized in that, In step S1, the reactive modifier system is prepared by mixing choline chloride, anhydrous citric acid and zinc acetate dihydrate in proportion, mixing in a high-speed mixer at a speed of 800-1000 rpm until a visually uniform white powder is formed, and then sealing and storing it in a dry container.

8. The method for preparing bio-based materials based on rose fiber according to claim 6, characterized in that, The specific process parameters for step S2 are: internal mixer rotor speed of 30-60 rpm, temperature of 80-90℃, and time of 8-12 minutes.

9. The method for preparing bio-based materials based on rose fiber according to claim 6, characterized in that, The specific process parameters for step S3 are: the internal mixer rotor speed is 60-100 rpm, the temperature is 130-140℃, and the time is 15-25 minutes.

10. A method for preparing bio-based materials based on rose fiber according to claim 6, characterized in that, In step S4, the temperature of the hot pressing conditions is 140-160℃, the pressure is 10-20MPa, and the holding time is 5-10 minutes.

Images