Bamboo fiber reinforced modified poly (butylene carbonate) as well as preparation method and application thereof
By blending modified bamboo fiber with polybutylene carbonate, the problems of low tensile strength and poor interfacial compatibility of polybutylene carbonate were solved, realizing the preparation of high-strength composite materials and expanding their application range.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-14
- Publication Date
- 2026-04-21
AI Technical Summary
Polybutylene carbonate has low tensile strength, which limits its application range. Existing inorganic doping modification has agglomeration problems, and fiber reinforcing agents have poor interfacial compatibility.
Bamboo fiber reinforced modified polybutylene carbonate was prepared by adding a dispersant to improve the agglomeration phenomenon of alkali-treated bamboo fibers and treating the surface of bamboo fibers with a silane coupling agent to improve their interfacial compatibility with polybutylene carbonate.
It improves the tensile strength of polybutylene carbonate, enhances the mechanical properties of the composite material, maintains biocompatibility and degradability, and expands its application in packaging materials, agricultural mulch films and biomedicine.
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Figure CN121895733A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polybutylene carbonate, and more specifically, to a bamboo fiber reinforced modified polybutylene carbonate, its preparation method, and its application. Background Technology
[0002] Polybutylene carbonate (PBC) is a member of the aliphatic polycarbonate family. It has advantages such as being non-toxic, non-polluting, biodegradable, and having good film-forming properties, and can be widely used in packaging materials, biomedicine, agricultural films, and other fields. However, due to its aliphatic linear structure, PBC has low tensile strength, which limits its application range. Physical methods are commonly used to improve the tensile strength of polybutylene carbonate (PBC), offering advantages such as low cost and simple process. These methods generally involve physical polymer blending and inorganic doping. Miao et al. (Engineering Plastics Application, 2023) prepared a polyhydroxyalkanoate (PHA) / PBC polymer alloy; when the PHA mass fraction was 10%, the tensile strength of the PHA / PBC alloy was 30.9 MPa. Wang et al. (Polymer Testing, 2012) prepared a PBC / PLA blend using a melt method. The two phases were uniformly mixed, and when the PBC / PLA mass ratio was 1:9, the tensile strength of the blend reached as high as 50.7 MPa. However, as the PBC content increased, the compatibility between the two phases deteriorated, and the performance decreased sharply. SiO2 can be uniformly dispersed in the PBC matrix and enhances the nucleation effect during cooling, thereby improving the crystallinity of PBC. Wang et al. (Journal of Thermal Analysis and Calorimetry, 2013) studied PBC / SiO2 composites. When the SiO2 addition exceeded 3% (w), the SiO2 nanoparticles hindered the segmental movement of the polymer chains, thus slightly increasing the Tg. The presence of SiO2 may hinder the combustion of organic matter and form a gas barrier during thermal decomposition to prevent volatile gases from permeating out of the composite, thereby improving the thermal stability of the nanocomposite. Zhao Zhuo (Blending Modification and Biodegradability Evaluation of Polybutylene Carbonate, 2022) prepared PBC / MgO nanocomposites by melt polycondensation, which were dispersed in the PBC matrix as reinforcements, enhancing the heterogeneous nucleation effect of PBC and improving the crystallinity and mechanical properties of the composite.
[0003] Inorganic doping modification of polycarbonate (PBC) is a simple, economical, and efficient process. Adding appropriate amounts of inorganic substances can improve the crystallinity and mechanical properties of the composite material. However, excessive addition can lead to particle agglomeration, resulting in a decrease in the material's mechanical properties. Current research on PBC modification mainly focuses on inorganic nanoparticles, and reports are limited. Fibers are excellent reinforcing agents for plastics, rubber, and biopolymers, and their influence on the structure and properties of PBC remains to be studied. To improve its mechanical properties and expand its practical applications in food packaging and agricultural films, fiber reinforcement can be added to enhance the mechanical properties of PBC. Natural bamboo fiber is a natural and renewable material with a high aspect ratio, large specific surface area, and low density (0.8 g / cm³). 3 Bamboo fiber, with its high strength (Young's modulus up to 359 GPa and tensile strength of 441 MPa), is known as "natural glass fiber." Its advantages, including high yield, low price, renewability, and biodegradability, make it an ideal reinforcing material for engineering structures, attracting widespread attention. However, the main components of natural bamboo fiber, such as cellulose, hemicellulose, and lignin, contain a large number of polar hydroxyl and phenolic hydroxyl functional groups, resulting in strong chemical polarity on its surface. This leads to a very clear interface between the two phases, creating a non-homogeneous system with poor adhesion. Consequently, the resulting natural bamboo fiber / polymer composites exhibit poor interfacial compatibility. Summary of the Invention
[0004] To address the aforementioned problems in existing technologies, this invention proposes a bamboo fiber-reinforced modified polybutylene carbonate (PBC). Specifically, it relates to a bamboo fiber-reinforced modified PBC, its preparation method, and its applications. This invention improves the agglomeration and compaction of bamboo fibers after alkali treatment by adding a dispersant. Then, through modification methods such as silane coupling agents, the surface polarity and microstructure of the bamboo fibers are improved, increasing the surface compatibility between bamboo fibers and polymer materials. This results in a material with excellent mechanical properties, biodegradability, and a controllable degradation cycle, suitable for composite films and other profiles, and applicable to packaging materials, biomedicine, agricultural mulch films, and other fields.
[0005] One objective of this invention is to provide a bamboo fiber reinforced modified polybutylene carbonate, comprising a blend of polybutylene carbonate and modified bamboo fiber; based on 100% of the total weight of the bamboo fiber reinforced modified polybutylene carbonate, it may contain the following components by weight percentage: Polybutylene carbonate 80-99%; Modified bamboo fiber 1~20%; The modified bamboo fiber mentioned above is bamboo fiber that has been treated with alkali and silane coupling agent.
[0006] The total weight of bamboo fiber reinforced modified polybutylene carbonate is 100%. The specific weight of polybutylene carbonate can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 93.5%, 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, or any value between the above values or a range between any two of the above values, such as 90~99%, 95~99%, etc.
[0007] The specific weight of modified bamboo fiber, taking the total weight of bamboo fiber-reinforced modified polybutylene carbonate as 100%, can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or any value between the above values or any range between any two of the above values, such as 1~10%, 1~5%, etc.
[0008] Specifically, the polybutylene carbonate can be a type of polybutylene carbonate commonly used in the art, and specifically, the Mn of the polybutylene carbonate can be 4000~50000. The specific value (g / mol) can be 4000, 5000, 6000, 8000, 10000, 12000, 14000, 15000, 16000, 18000, 19000, 20000, 22000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, 32000, 33000, 34000, 35000, 36000, 38000, 40000, 42000, 43000, 44000, 45000, 46000, 48000, 50000 g / mol or any value between the above values or a range between any two of the above values; Mw can be 60000~350000 g / mol. The value can be 60000, 70000, 80000, 90000, 100000, 120000, 140000, 150000, 160000, 180000, 200000, 220000, 240000, 260000, 280000, 300000, 320000, 330000, 340000, 350000 g / mol, or any value between the above values, or a range between any two of the above values.
[0009] The second objective of this invention is to provide a method for preparing bamboo fiber reinforced modified polybutylene carbonate as described in the first objective of this invention, which may include the following steps: Step 1, Surface modification of bamboo fiber: Add bamboo fiber and dispersant to an alkaline solution to obtain a reaction solution. Stir, wash, filter, and dry to obtain alkaline-treated bamboo fiber. Take an alcohol-water solution, adjust the pH, add a silane coupling agent to obtain a mixed solution, hydrolyze, add the alkaline-treated bamboo fiber again, stir, wash, filter, and dry to obtain modified bamboo fiber, namely, the bamboo fiber treated with alkali and silane coupling agent.
[0010] Regarding step 1, this invention improves the surface polarity of bamboo fibers through surface modification, enhancing the interfacial compatibility between PBC and bamboo fibers, and improving the mechanical properties of the PBC / bamboo fiber composite material. Alkali treatment can remove hemicellulose and pectin from bamboo fibers, making them finer; however, alkaline treatment can easily lead to agglomeration and clumping of the bamboo fibers, affecting the subsequent silane coupling agent treatment. This application further employs a dispersant, which promotes uniform dispersion of material particles in the medium. Through steric hindrance and electrostatic stabilization, the dispersant prevents particle aggregation and increases the stability of the suspension. Adding a dispersant during treatment can improve the agglomeration and clumping phenomenon that occurs with alkaline-treated bamboo fibers, which is beneficial for subsequent silane coupling agent treatment and polymer blending.
[0011] Step 2, Bamboo Fiber Reinforced Modified Polybutylene Carbonate: The components, including polybutylene carbonate and modified bamboo fiber, are melt-blended to obtain the bamboo fiber reinforced modified polybutylene carbonate. Preferably, the melt-blending temperature is 90~130℃.
[0012] In the preparation method of bamboo fiber reinforced modified polybutylene carbonate according to the present invention, it may specifically include surface modification of bamboo fiber and bamboo fiber reinforced modified polybutylene carbonate, and the preparation method may specifically include the following steps: Step 1: Surface modification of bamboo fiber: Add 80-100 parts by weight of alkaline solution, 1-20 parts by weight of 200-2000 mesh bamboo fiber, and dispersant to a reactor. Stir for 5-24 hours, wash with deionized water until the pH of the supernatant reaches 7, filter, and dry in an electric heating oven at 80-100℃ to obtain alkali-treated bamboo fiber. Prepare 100 parts by weight of an alcohol-water solution, and adjust the pH to 3.5-5.5 (e.g., 3.5, 4.0, 4.5, 5.0, 5.5 or...) with acid. Add any value between the above values or the range between any two of the above values), add a silane coupling agent and hydrolyze for 0.5-2 hours (e.g., 0.5, 1.0, 1.5, 2.0 hours or any value between the above values or the range between any two of the above values), add 1-20 parts by weight of alkali to treat bamboo fiber, stir for 1-8 hours, wash with deionized water until the pH of the supernatant is 7, filter, and dry in an electric heating blast oven at 80-100℃ to obtain the modified bamboo fiber.
[0013] Step 2, Bamboo fiber reinforced modified polybutylene carbonate: Add polybutylene carbonate to the screw extruder to modify bamboo fiber, and melt extrude to obtain bamboo fiber reinforced modified polybutylene carbonate.
[0014] In some specific embodiments of the present invention, In step 1, The alkaline solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution; preferably, the concentration of the alkaline solution is 1-10 wt% (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between the above values or a range between any two of the above values); and / or, The bamboo fiber is 200-2000 mesh bamboo fiber, specifically, for example, 200, 500, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000 mesh or any value between the above values or a range between any two of the above values; and / or, The washing is performed with deionized water until the pH of the supernatant is 7; and / or, The drying temperature is 80-100℃; and / or, The hydrolysis time is 0.5-3 hours; and / or, The acid used to adjust the pH is at least one of acetic acid, carbonic acid, phosphoric acid, and silicic acid.
[0015] In some specific embodiments of the present invention, In step 1, The weight ratio of the alkaline solution to bamboo fiber is (80-100):(1-20), preferably (85-95):(5-15); and / or, The weight ratio of the alcohol-water solution to the alkali-treated bamboo fiber is 100:(1-20), for example, 100:1, 100:2, 100:3, 100:4, 100:5, 100:6, 100:7, 100:8, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15, 100:16, 100:17, 100:18, 100:19, 100:20, or any value between the above values or a range between any two of the above values.
[0016] In step 1, The dispersant may be selected from one or more of sodium hexametaphosphate, sodium pyrophosphate, sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, and sodium polyacrylate. Specifically, the amount of the dispersant can be 0.1-2 wt% of the weight of the bamboo fiber, for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1.0 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, or any value between the above values or a range between any two of the above values. And / or, In step 1, The alcohol-water solution may be a mixture of alcohol and water; Specifically, the weight ratio of alcohol to water can be (10~1.5):1, preferably (5~3):1; for example, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4.5:1, 4:1, 3.5:1, 3:1, 2:1, 1.5:1 or any value between the above values or a range between any two of the above values; preferably, the alcohol is methanol and / or ethanol; more preferably, ethanol is used when the silane coupling agent is an ethoxysilane coupling agent, and methanol is used when the silane coupling agent is a methoxysilane coupling agent.
[0017] In step 1, The silane coupling agent may be selected from one or more of the following: aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, isocyanatetriethoxysilane, isocyanatetrimethoxysilane, methacryloxypropyltrichlorosilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, and mercaptopropyltriethoxysilane. Specifically, the amount of the silane coupling agent can be 1-10 wt% of the total weight of the mixture, for example, it can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, or any value between the above values or a range between any two of the above values.
[0018] In step 2, The weight ratio of the modified bamboo fiber to polybutylene carbonate can be (1-20):(80-99); for example, it can be 1 / 99, 2 / 98, 3 / 97, 4 / 96, 5 / 95, 6 / 94, 7 / 93, 8 / 92, 9 / 91, 10 / 90, 11 / 89, 12 / 88, 13 / 87, 14 / 86, 15 / 85, 16 / 84, 17 / 83, 18 / 82, 19 / 81, 20 / 80 or any value between the above values or a range between any two of the above values, such as (1~10):(90~99), (1~5):(95~99), etc.
[0019] More specifically, The preparation method of bamboo fiber reinforced modified polybutylene carbonate according to the present invention may include the following steps: (1) Prepare an alkaline solution with a concentration of 1-10 wt% (the alkaline solution includes sodium hydroxide solution, potassium hydroxide solution, calcium hydroxide solution, preferably sodium hydroxide solution), add 200-2000 mesh bamboo fiber, and 0.1-2 wt% of the weight of bamboo fiber dispersant (the dispersant includes one or more of sodium hexametaphosphate, sodium pyrophosphate, sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, and sodium polyacrylate, preferably polyvinylpyrrolidone), stir at room temperature for 5-24 h, wash with deionized water until the supernatant is neutral, filter, dry at 85-100℃ to constant weight, and store for later use.
[0020] (2) Prepare an alcohol-water solution, adjust the pH to 3.5-5.5, add a silane coupling agent (the silane coupling agent includes one or more of aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, isocyanate triethoxysilane, isocyanate trimethoxysilane, methacryloyloxypropyltrichlorosilane, methacryloyloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, preferably aminopropyltriethoxysilane), hydrolyze, add the bamboo fiber treated with alkali in step (1), stir, wash with deionized water until the supernatant is neutral, filter, dry at 80-100℃ to constant weight, and store for later use.
[0021] (3) The modified bamboo fiber and polybutylene carbonate obtained in step (2) are blended and added to a screw extruder. The front end temperature is 100℃-130℃ and the rear end temperature is 90-110℃. The bamboo fiber reinforced modified polybutylene carbonate is melt-extruded to obtain the composite material. The obtained composite material is then sheared and granulated for later use.
[0022] Optionally, (4) in a flat fluidized bed, the prepared standard dumbbell-shaped specimen can be hot-pressed by a mold to test its mechanical and thermodynamic properties.
[0023] Optionally, (5) the bamboo fiber reinforced modified polybutylene carbonate material obtained by melt extrusion in step (3) is blow-molded to obtain a bamboo fiber reinforced modified polybutylene carbonate composite film, which can be used in packaging materials, agricultural mulch films, biomedical and other technical fields. The blow molding process can be performed using conventional methods in this field, for example, the melt temperature can be 90-130℃, the mold temperature can be 10-25℃, and the blow molding pressure can be 0.2-0.6MPa. Specific adjustments can be made according to actual conditions.
[0024] The third objective of this invention is to provide bamboo fiber reinforced modified polybutylene carbonate obtained by the preparation method described in the second objective of this invention.
[0025] The fourth objective of this invention is to provide the preparation method described in this invention or the application of the bamboo fiber reinforced modified polybutylene carbonate described in this invention, preferably in biodegradable packaging materials, agricultural mulch films, and biomedical products.
[0026] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships, such as A and / or B. Specifically, it can mean that A and B can be included at the same time, A can exist alone, or B can exist alone, and any of the above three situations can be met.
[0027] Regarding the technical effects of the present invention (1) This invention uses bamboo fiber as a polymer reinforcement, which breaks the predicament of the shortage of carbon fiber reinforcement resources derived from petrochemical resources. Moreover, bamboo fiber is inexpensive, biodegradable, and renewable, which helps to reduce costs and promote the use of biodegradable PBC. (2) By adding a dispersant during alkaline pretreatment, the phenomena of caking and agglomeration after alkaline treatment are improved, thus avoiding the impact on the effect of subsequent surface treatment. The dispersibility is good, and after treatment with silane coupling agent, the number of polar functional groups such as hydroxyl and phenolic hydroxyl groups on the surface of bamboo fiber is reduced, thereby reducing the surface polarity. (3) After alkali treatment and silane coupling agent modification, the added silane coupling agent becomes a bridge between the fiber and the matrix, which improves the interfacial compatibility between bamboo fiber and polybutylene carbonate, allowing the fiber to be impregnated in the polybutylene carbonate matrix, reducing the fiber from being pulled out of the matrix. During deformation, defects are reduced and stress can be effectively transferred, so that the modified fiber / polybutylene carbonate composite material can maintain a high elongation at break of 441% while the tensile strength is increased to a maximum of 51.4 MPa, which is 49.8% higher than that of pure PBC; (4) While improving the mechanical properties of polybutylene carbonate, it maintains its biocompatibility and degradability. The degradation ability of PBC is regulated by adding bamboo fiber, which not only meets the needs of agricultural mulch film, plastic packaging and other fields, but also expands its application in medical dressings, sustained-release drug carriers and other fields. Attached Figure Description
[0028] Figure 1 The Fourier transform infrared spectra of bamboo fiber after different modification treatments are shown. Detailed Implementation
[0029] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.
[0030] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0031] Source of raw materials Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.
[0032] Polybutylene carbonate, Mn=43603 g / mol, Mw=60711 g / mol, Tm=58℃, Tg=-32℃; Its preparation method can be referred to the following existing technical literature: Liao J, Sun S, Wang M, et al. Synthesis and characterization of high molecular weight poly(butylene carbonate) from dimethyl carbonate[J]. Journal of Polymer Research, 2025, 32(7).DOI:10.1007 / s10965-025-04481-2. Bamboo fiber, Chongqing Ruizhu Plant Fiber Products Co., Ltd., 2000 mesh.
[0033] Example 1 1. Sample preparation Add 300ml of deionized water to a 500ml beaker, then add 15g of NaOH and stir until the NaOH is completely dissolved. Cool to room temperature to obtain a 5wt% NaOH solution. Add 25g of bamboo fiber (2000 mesh) to the 5wt% NaOH solution, along with 0.5wt% (by weight of the bamboo fiber) of polyvinylpyrrolidone dispersant. Stir at room temperature for 10 hours, then wash with deionized water. Filter off the supernatant. Repeat the above steps until the supernatant is neutral. Filter to obtain bamboo fiber, then place it in a forced-air drying oven at 85℃ and dry for 20 hours until constant weight is achieved, obtaining alkali-treated bamboo fiber.
[0034] 2. Characterization and Testing The composition of major elements (C, O, Si, etc.) on the surface of bamboo fiber was determined using a Thermo Fisher K-Alpha X-ray photoelectron spectroscopy system. The C1s signal peak was analyzed by curve fitting using XPS peak analysis and Avantage 5.979 software.
[0035] The FTIR spectra of the synthesized polymer samples were recorded using KBr tablets on a Nicolet iS5 FTIR spectrometer. All Fourier transform infrared spectra were collected at room temperature in the scan range of 400–4000 cm⁻¹ with a resolution of 4.0 cm⁻¹.
[0036] 3. Comparison and Analysis of Test Results XPS testing revealed a change in the C / O ratio on the surface of bamboo fibers, indicating that alkali treatment removed pectin and hemicellulose from the bamboo fiber surface, exposing phenolic hydroxyl groups and thus increasing the O content. See Table 1 for details.
[0037] Fourier transform infrared spectroscopy revealed that alkali-treated bamboo fibers at 2920 cm⁻¹ -1 With 3330 cm -1 The absorption peak intensity was enhanced compared to untreated fibers, indicating an increase in the hydroxyl and cellulose content of bamboo fibers after alkali treatment. (At 1745-1725 cm⁻¹) -1 The weakening of the characteristic peak indicates that the hemicellulose content of bamboo fiber decreases after alkali treatment. Therefore, alkali treatment removes impurities and other substances from the surface of the bamboo fiber, allowing more cellulose to be exposed. See details. Figure 1 .
[0038] Example 2 1. Sample preparation Step 1: Add 3 parts of polybutylene carbonate and unmodified 200, 600 and 2000 mesh bamboo fibers to a screw extruder at a mass ratio of 97 / 3. The front end temperature is 120℃ and the rear end temperature is 105℃. Melt extrusion is performed to obtain polybutylene carbonate / bamboo fiber composite material. Then, the obtained composite material is sheared and granulated for later use.
[0039] Step 2: Fill the polybutylene carbonate / bamboo fiber composite material particles obtained in Step 1 into a flat vulcanizing bed mold. Set the upper mold temperature to 105℃ and the lower mold temperature to 105℃. Plasticize for 10 minutes, hot press for 5 minutes, and cool for 20 minutes to obtain polybutylene carbonate / bamboo fiber composite material samples.
[0040] 2. Characterization and Testing The substrate dimensions and overlap area were in accordance with GB / T7124-2008. The overlap shear properties of the polyacrylate adhesive were tested using an electronic universal testing machine. The tensile rate was 5 mm / min, the test temperature was room temperature, and 5 samples were tested in each group, and the average value was taken.
[0041] 3. Comparison and analysis of test results The tensile strength of PBC / 200 mesh bamboo fiber is 33.5 MPa, that of PBC / 600 mesh bamboo fiber is 34.2 MPa, and that of PBC / 2000 mesh bamboo fiber is 36.4 MPa. The mechanical properties of the composite material increase with decreasing particle size because the dispersion of bamboo fiber is enhanced, resulting in more uniform dispersion within the PBC matrix and preventing defects such as agglomeration. See Table 2 for details. Therefore, 2000 mesh bamboo fiber is preferred for experimental use in this application.
[0042] Example 3 1. Sample preparation Step 1: Prepare alkali-treated bamboo fiber according to step 1 in Example 1.
[0043] Step 2: Add 240ml of deionized water and 60ml of ethanol to a 500ml beaker to prepare an ethanol-water solution (ethanol / water: 80 / 20). Adjust the pH to 4-5 with acetic acid, add the silane coupling agent triaminopropyltriethoxysilane coupling agent (KH550), and obtain a mixture. The amount of silane coupling agent used is 3wt% of the mixture. Stir and hydrolyze for 30 min. Weigh 40g of the bamboo fiber prepared in Step 1 and add it to the hydrolyzed silane coupling agent solution. Stir at room temperature for 4 h, then add deionized water to wash, filter off the supernatant, and repeat the above steps until the supernatant is neutral. Filter to obtain bamboo fiber, then place it in a forced-air drying oven at 85℃ and dry for 20 h until constant weight is obtained to obtain modified bamboo fiber.
[0044] Step 3: Add polybutylene carbonate and the modified bamboo fiber obtained in step 2 to a screw extruder in a mass ratio of 99 / 1, 97 / 3, 95 / 5, and 80 / 20. The front end temperature is 120°C and the rear end temperature is 105°C. Melt extrusion is performed to obtain a polybutylene carbonate / modified bamboo fiber composite material, which is bamboo fiber reinforced modified polybutylene carbonate. Then, the obtained composite material is sheared and granulated for later use.
[0045] Step 4: Fill the bamboo fiber reinforced modified polybutylene carbonate granules obtained in step 3 into a flat vulcanizing bed mold. Set the upper mold temperature to 105℃ and the lower mold temperature to 105℃. Plasticize for 10 minutes, hot press for 5 minutes, and cool for 20 minutes to obtain bamboo fiber reinforced modified polybutylene carbonate material samples.
[0046] 2. Characterization and Testing The characterization is the same as in Examples 1 and 2.
[0047] 3. Comparison and Analysis of Test Results XPS testing revealed a Si content of 1.42% in the bamboo fiber, indicating that the silane coupling agent was successfully grafted onto the surface of the bamboo fiber (see Table 1 for details). Fourier transform infrared spectroscopy showed that the silane-modified bamboo fiber exhibited high Si content at 1050 cm⁻¹. -1 The stretching vibration peak of CO is significantly enhanced, mainly because the stretching vibration peak of Si-O in the silane molecule also appears at this position, at 1157 cm⁻¹. -1 The enhanced absorption peak intensity at this point is mainly due to the reaction of silane hydrolysis products with hydroxyl groups on the bamboo fiber surface to form Si-OC covalent bonds. See details... Figure 1 .
[0048] The addition of KH550-treated bamboo fiber increased the tensile strength of polybutylene carbonate (PBC) from 34.3 MPa to 51.4 MPa, an increase of 49.8% (see Table 2). KH550 silane coupling agent modified bamboo fiber improved the interfacial compatibility between the bamboo fiber and the matrix material, ensuring complete fiber wetting within the PBC matrix, thereby reducing fiber pull-out and improving the mechanical properties of PBC. With increasing bamboo fiber content, the tensile strength of the composite material initially increased and then decreased. This is presumably because with increased addition, the bamboo fiber became unevenly dispersed, leading to agglomeration, disrupting the continuity of the matrix, and causing problems such as pores and gaps. This resulted in poor stress transmission, stress concentration, and a decline in the mechanical properties of the composite material.
[0049] Example 4 1. Sample preparation Step 1: Prepare alkali-treated bamboo fiber according to step 1 in Example 1.
[0050] Step 2: Add 240ml of deionized water and 60ml of methanol to a 500ml beaker to prepare a methanol-water solution (alcohol / water: 80 / 20). Adjust the pH to 4-5 with acetic acid, add isocyanate trimethoxysilane coupling agent (IPTS) to obtain a mixture, wherein the amount of silane coupling agent is 3wt% of the mixture, and stir for 30 min for hydrolysis. Weigh 40g of the bamboo fiber prepared in step 1 and add it to the hydrolyzed silane coupling agent solution, stir at room temperature for 4 h, then add deionized water to wash, filter off the supernatant, repeat the above steps until the supernatant is neutral, filter to obtain bamboo fiber, and then put it in a forced-air drying oven at 85℃ for 20 h until constant weight is obtained to obtain modified bamboo fiber.
[0051] Step 3: Add polybutylene carbonate and the modified bamboo fiber obtained in step 2 to a screw extruder at a mass ratio of 97 / 3. The front end temperature is 120℃ and the rear end temperature is 105℃. Melt extrusion is performed to obtain polybutylene carbonate / modified bamboo fiber composite material, which is bamboo fiber reinforced modified polybutylene carbonate. Then, the obtained composite material is sheared and granulated for later use.
[0052] Step 4: Fill the bamboo fiber reinforced modified polybutylene carbonate material particles obtained in step 3 into a flat vulcanizing bed mold. Set the upper mold temperature to 105℃ and the lower mold temperature to 105℃. Plasticize for 10 minutes, hot press for 5 minutes, and cool for 20 minutes to obtain bamboo fiber reinforced modified polybutylene carbonate material samples.
[0053] 2. Characterization and Testing Characterization and testing were performed in the same manner as in Examples 1 and 2.
[0054] 3. Comparison and Analysis of Test Results XPS testing revealed a Si content of 0.68% in the bamboo fiber, indicating that the silane coupling agent was successfully grafted onto the surface of the bamboo fiber (see Table 1 for details). Fourier transform infrared spectroscopy showed that the silane-modified bamboo fiber exhibited high Si content at 1050 cm⁻¹. -1 The stretching vibration peak of CO is significantly enhanced, mainly because the stretching vibration peak of Si-O in the silane molecule also appears at this position, at 1157 cm⁻¹. -1 The enhanced absorption peak intensity at this point is mainly due to the reaction of silane hydrolysis products with hydroxyl groups on the bamboo fiber surface to form Si-OC covalent bonds. See details... Figure 1 .
[0055] The addition of IPTS-treated bamboo fiber increased the tensile strength of polybutylene carbonate (PBC) from 34.3 MPa to 38.5 MPa, an increase of 12.3% (see Table 2 for details). IPTS silane coupling agent modification of bamboo fiber improved the interfacial compatibility between the bamboo fiber and the matrix material, ensuring complete fiber wetting within the PBC matrix, thereby reducing fiber pull-out and improving the mechanical properties of PBC.
[0056] Example 5 1. Sample preparation Step 1: Prepare alkali-treated bamboo fiber according to step 1 in Example 1.
[0057] Step 2: Add 240ml of deionized water and 60ml of methanol to a 500ml beaker to prepare a methanol-water solution (alcohol / water: 80 / 20). Adjust the pH to 4-5 with acetic acid, add vinyltrimethoxysilane coupling agent (AP171), and obtain a mixture, wherein the amount of vinyltrimethoxysilane coupling agent is 3wt% of the mixture. Stir and hydrolyze for 30 min. Weigh 40g of the bamboo fiber prepared in Step 1 and add it to the hydrolyzed silane coupling agent solution. Stir at room temperature for 4 h, then add deionized water to wash, filter off the supernatant, and repeat the above steps until the supernatant is neutral. Filter to obtain bamboo fiber, then place it in a forced-air drying oven, set the temperature to 85℃, and dry for 20 h until constant weight is obtained to obtain modified bamboo fiber.
[0058] Step 3: Add polybutylene carbonate and the modified bamboo fiber obtained in step 2 to a screw extruder at a mass ratio of 97 / 3. The front end temperature is 120℃ and the rear end temperature is 105℃. Melt extrusion is performed to obtain polybutylene carbonate / modified bamboo fiber composite material, which is bamboo fiber reinforced modified polybutylene carbonate. The obtained composite material is then sheared and granulated for later use.
[0059] Step 4: Fill the bamboo fiber reinforced modified polybutylene carbonate material particles obtained in step 3 into a flat vulcanizing bed mold. Set the upper mold temperature to 105℃ and the lower mold temperature to 105℃. Plasticize for 10 minutes, hot press for 5 minutes, and cool for 20 minutes to obtain bamboo fiber reinforced modified polybutylene carbonate material samples.
[0060] 2. Characterization and Testing Characterization and testing were performed in the same manner as in Examples 1 and 2.
[0061] 3. Comparison and Analysis of Test Results XPS testing revealed a Si content of 0.51% in the bamboo fiber, indicating that the silane coupling agent was successfully grafted onto the surface of the bamboo fiber (see Table 1 for details). Fourier transform infrared spectroscopy showed that the silane-modified bamboo fiber exhibited high Si content at 1050 cm⁻¹. -1 The stretching vibration peak of CO is significantly enhanced, mainly because the stretching vibration peak of Si-O in the silane molecule also appears at this position, at 1157 cm⁻¹. -1 The enhanced absorption peak intensity at this point is mainly due to the reaction of silane hydrolysis products with hydroxyl groups on the bamboo fiber surface to form Si-OC covalent bonds. See details... Figure 1 .
[0062] The addition of AP171-treated bamboo fibers increased the tensile strength of polybutylene carbonate (PBC) from 34.3 MPa to 40.7 MPa, an increase of 18.7% (see Table 2 for details). AP171 silane coupling agent modified bamboo fibers improved the interfacial compatibility between the bamboo fibers and the matrix material, ensuring complete fiber wetting within the PBC matrix, thereby reducing fiber pull-out and improving the mechanical properties of the PBC.
[0063] Example 6 1. Sample preparation Step 1: Prepare alkali-treated bamboo fiber according to step 1 in Example 1.
[0064] Step 2: Add 240ml of deionized water and 60ml of ethanol to a 500ml beaker to prepare an ethanol-water solution (ethanol / water: 80 / 20). Adjust the pH to 4-5 with acetic acid, add triaminopropyltriethoxysilane coupling agent (KH550) to obtain a mixture, wherein the amount of silane coupling agent is 3wt% of the mixture, and stir for 30 min for hydrolysis. Weigh 40g of the bamboo fiber prepared in step 1 and add it to the hydrolyzed silane coupling agent solution, stir at room temperature for 4 h, then add deionized water to wash, filter off the supernatant, repeat the above steps until the supernatant is neutral, filter to obtain bamboo fiber, then put it in a forced-air drying oven, set the temperature to 85℃, and dry for 20 h until constant weight is obtained to obtain modified bamboo fiber.
[0065] Step 3: Add polybutylene carbonate and the modified bamboo fiber obtained in step 2 to a screw extruder at a mass ratio of 97 / 3. The front end temperature is 120℃ and the rear end temperature is 105℃. Melt extrusion is performed to obtain bamboo fiber reinforced modified polybutylene carbonate material. Then, the obtained composite material is sheared and granulated for later use.
[0066] Step 4: Fill the bamboo fiber reinforced modified polybutylene carbonate material granules obtained in step 3 into a blow molding machine and blow mold them into a film. During blow molding, the melt temperature can be 90-130℃, the mold temperature can be 20℃, and the blow molding pressure can be 0.2-0.6MPa to obtain a bamboo fiber reinforced modified polybutylene carbonate film with a thickness of 0.1mm, which is used for agricultural mulch film.
[0067] 2. Characterization and Testing A phosphate buffer solution (pH 6.86) containing Pseudomonas lipase (activity 46.2 U / mg) was prepared, wherein the concentration of Pseudomonas lipase in the phosphate buffer solution was 1.5 g / L. Enzymatic degradation was performed on bamboo fiber reinforced modified polybutylene carbonate membrane (PBC / BF) and polybutylene carbonate membrane (prepared by blow molding of pure polybutylene carbonate, the preparation method is the same as step 4 of Example 6, the membrane thickness is 0.1 mm) at 35 °C.
[0068] 3. Comparison and Analysis of Test Results Table 3 shows the weight loss rates of PBC membrane and PBC / BF membrane over time. The addition of bamboo fiber can slow down the early degradation of PBC, improve the stability of PBC, and accelerate degradation in the later stage, thus achieving the purpose required for agricultural production.
[0069] Table 1. C, O, and Si content of bamboo fiber after different modification treatments
[0070] Table 2. Mechanical property parameters of different treatments
[0071] Table 3. Weight loss rate (%) of PBC and PBC / BF
[0072] As shown in Table 3, the degradation rate of the PBC / BF composite material after adding bamboo fiber was lower than that of the pure PBC material at 2, 4, 6 and 8 weeks. This indicates that adding bamboo fiber can slow down the degradation of PBC and prolong the degradation time, which is beneficial to the application of PBC material in daily life.
Claims
1. A bamboo fiber reinforced modified polybutylene carbonate, characterized in that... It contains blends of polybutylene carbonate and modified bamboo fiber; The modified bamboo fiber mentioned above is bamboo fiber that has been treated with alkali and silane coupling agent; Preferably, the bamboo fiber-reinforced modified polybutylene carbonate comprises, by weight percentage, the following components, based on 100% of the total weight: Polybutylene carbonate 80-99%; Modified bamboo fiber 1~20%; Preferably, the polybutylene carbonate has Mn = 4000~50000 g / mol and Mw = 60000~350000 g / mol.
2. The preparation method of bamboo fiber reinforced modified polybutylene carbonate according to claim 1, comprising the following steps: Step 1, Surface modification of bamboo fiber: Add bamboo fiber and dispersant to alkaline solution to obtain reaction solution, stir, wash, filter, dry to obtain alkali-treated bamboo fiber; Take an alcohol-water solution, adjust the pH, add a silane coupling agent to obtain a mixture, hydrolyze it, then add alkali to treat the bamboo fiber, stir, wash, filter, and dry to obtain the modified bamboo fiber. Step 2: Preparation of bamboo fiber reinforced modified polybutylene carbonate: The components, including polybutylene carbonate and the modified bamboo fiber, are melt-blended to obtain the bamboo fiber reinforced modified polybutylene carbonate; preferably, the melt-blending temperature is 90~130℃.
3. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: In step 1, The alkaline solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, and calcium hydroxide solution; preferably, the concentration of the alkaline solution is 1-10 wt%. And / or, The bamboo fiber is 200-2000 mesh bamboo fiber.
4. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: In step 1, The weight ratio of the alkaline solution to bamboo fiber is (80-100):(1-20); and / or, The weight ratio of the alcohol-water solution to the alkali-treated bamboo fiber is 100:(1-20).
5. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: The washing is performed with deionized water until the pH of the supernatant is 7; and / or, The drying temperature is 80-100℃; and / or, The hydrolysis time is 0.5-3 hours; and / or, The acid used to adjust the pH is at least one of acetic acid, carbonic acid, phosphoric acid, and silicic acid.
6. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: In step 1, The dispersant is selected from one or more of sodium hexametaphosphate, sodium pyrophosphate, sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, and sodium polyacrylate. Preferably, the amount of the dispersant is 0.1-2 wt% of the weight of the bamboo fiber.
7. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: In step 1, The alcohol-water solution is a mixture of alcohol and water; The preferred weight ratio of alcohol to water is (10~1.5):1, and more preferably (5~3):1; The preferred alcohols are methanol and / or ethanol; more preferably, ethanol is used when the silane coupling agent is an ethoxysilane coupling agent, and methanol is used when the silane coupling agent is a methoxysilane coupling agent.
8. The method for preparing bamboo fiber reinforced modified polybutylene carbonate according to claim 2, characterized in that: In step 1, The silane coupling agent is selected from one or more of the following: aminopropyltriethoxysilane, aminopropyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, isocyanatetriethoxysilane, isocyanatetrimethoxysilane, methacryloxypropyltrichlorosilane, methacryloxypropyltrimethoxysilane, mercaptopropyltrimethoxysilane, and mercaptopropyltriethoxysilane. Preferably, the amount of the silane coupling agent is 1-10 wt% of the total weight of the mixture.
9. Bamboo fiber reinforced modified polybutylene carbonate obtained by the preparation method according to any one of claims 2 to 8.
10. The application of bamboo fiber reinforced modified polybutylene carbonate according to claim 1 or 9, or the preparation method according to any one of claims 2 to 8, is preferably used in biodegradable packaging materials, agricultural mulch films, or biomedical products.