Preparation and application of a bio-based modified fly ash cenospheres composite polypropylene material

Abstract

This invention belongs to the field of polymer composite material technology, specifically relating to the preparation and application of a bio-based modified fly ash microsphere composite polypropylene material. The material comprises, by mass percentage: 55%~75% polypropylene, 15%~35% fly ash microspheres, 1%~4% vegetable oil-derived modifier, 0.1%~0.5% antioxidant, 4%~13% interface compatibilizer, and 0.1%~1% other additives. First, the fly ash microspheres are activated with alkali solution and then liquid-phase grafted with the vegetable oil-derived modifier to obtain bio-based modified fly ash microspheres, which are then mixed with the remaining components. The mixture is then fed into a twin-screw extruder for melt extrusion and cold-cut granulation to obtain a composite masterbatch. The masterbatch is then dried and injection molded to produce samples or specimens of the bio-based modified fly ash microsphere composite polypropylene material, exhibiting a flexural strength ≥28 MPa, a flexural modulus ≥1250 MPa, and an unnotched impact strength ≥46 kJ / m². 2 The bio-based modified fly ash microspheres of this invention are uniformly dispersed in a polypropylene system, and can absorb impact energy to achieve in-situ toughening of the interface.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials technology, specifically relating to the preparation and application of a bio-based modified fly ash microsphere composite polypropylene material. Background Technology

[0002] Polypropylene (PP), as a general-purpose thermoplastic resin material, plays an irreplaceable and important role in automobile manufacturing, appliance housings, pipes, and packaging due to its low density, ease of processing, chemical resistance, and excellent comprehensive mechanical properties. However, PP's high crystallinity leads to inherent defects such as high notch sensitivity and poor impact toughness, which severely limits its application range.

[0003] Currently, the industry mainly adopts two technical routes for toughening and reinforcing polypropylene: one is to introduce elastomers (such as POE, EPDM, etc.) into PP for blending and toughening; the other is to add conventional inorganic rigid fillers (such as talc, calcium carbonate, etc.) for filling and reinforcement. However, both methods have obvious technical limitations: although the introduction of elastomers can significantly improve the fracture toughness of composite materials, it inevitably reduces the stiffness and tensile strength of the material significantly; while conventional inorganic rigid fillers can improve rigidity, they often further deteriorate the impact toughness of the material, and their high density means that adding large amounts of them violates the original intention of lightweighting.

[0004] Fly ash microspheres (FAC), as a special functional waste extractant, possess the following advantages: 1) Their unique regular spherical structure not only enables material lightweighting but also improves processing fluidity and stress distribution under stress; 2) Their main components are SiO2 and Al2O3, which significantly enhance the rigidity and heat resistance of composite materials. However, directly applying fly ash microspheres to polypropylene systems still faces significant bottlenecks: On the one hand, polypropylene is a typical non-polar polymer, while the surface of the microspheres is highly polar, resulting in severe thermodynamic incompatibility and extremely poor interfacial adhesion; on the other hand, the microspheres are prone to agglomeration in the PP melt, forming stress concentration points.

[0005] To address the aforementioned interface issues, traditional processes often employ petrochemical coupling agents such as silanes and aluminates to treat the surface of inorganic fillers. However, due to their extremely short molecular chains, these agents can only form a rigid bonding layer on the surface of the microspheres, failing to absorb impact energy to solve the material embrittlement problem. Furthermore, their processing easily releases VOCs, which is inconsistent with environmental protection trends. Summary of the Invention

[0006] To address the problems of easy agglomeration of fly ash microspheres and poor interfacial adhesion due to incompatibility when directly applied to polypropylene systems, this invention provides a green modification strategy for fly ash microspheres that balances interfacial compatibility and rigidity / toughness. This strategy introduces a natural bio-based modifier rich in long carbon chains to construct a highly elastic buffer layer in situ on the surface of the microspheres. This interface not only promotes uniform dispersion of powders applied to polypropylene systems but also absorbs impact energy, achieving in-situ toughening of the interface and completely solving the problem of the contradiction between rigidity and toughness.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A bio-based modified fly ash microsphere composite polypropylene material comprises, by mass percentage: 55%~75% polypropylene, 15%~35% fly ash microspheres, 1%~4% vegetable oil-derived modifier, 0.1%~0.5% antioxidant, 4%~13% interface compatibilizer, and 0.1%~1% other additives; wherein the fly ash microspheres are activated by alkaline solution and then liquid-phase grafted with vegetable oil-derived modifier to obtain bio-based modified fly ash microspheres, which are then mixed and dispersed with the remaining components in a polypropylene matrix.

[0008] Furthermore, the method for obtaining the aforementioned bio-based modified fly ash microspheres is as follows: Fly ash microspheres were placed in an alkaline solution with a concentration of 1-3 mol / L and stirred at a constant temperature of 60-80℃ for 2-4 hours; then filtered, washed, and dried to obtain activated fly ash microspheres. The vegetable oil-derived modifier was dissolved in 5 to 10 times its weight of anhydrous ethanol and then ultrasonically dispersed to form a modifier solution. The activated fly ash microspheres were added to a reactor equipped with a reflux condenser, and anhydrous ethanol was added to disperse the mixture. The modifier solution was then slowly added dropwise while stirring until the mixture was completely dissolved. The mixture was refluxed at a constant temperature of 70-80°C and a rotation speed of 500-800 rpm for 4-6 hours. The mixture was then filtered under reduced pressure while hot, and the filter cake was washed repeatedly with anhydrous ethanol 3-5 times. The mixture was then vacuum dried at 80-100°C for 8-12 hours. After complete drying, the mixture was ground and sieved to obtain the bio-based modified fly ash microspheres.

[0009] Furthermore, the plant oil-derived modifier is one or more of epoxidized linseed oil, epoxidized soybean oil, and cashew phenol.

[0010] Furthermore, the fly ash has a relative density of 2.3–2.4 g / cm³. 3 It is a grayish-white powder with a particle size of 1 to 10 micrometers, preferably with an average particle size of 4.6 micrometers.

[0011] Furthermore, the polypropylene is homopolymer polypropylene or block copolymer polypropylene with a melt flow rate of 2~60g / 10min under test conditions of 230 ℃ and 2.16 kg; preferably, the crystallinity of the homopolymer polypropylene is above 70% and the isotacticity is greater than 99%, and the comonomer of the block copolymer polypropylene is ethylene, with a molar content of ethylene monomer repeating units of 4%~10%.

[0012] Furthermore, the antioxidant is one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants; preferably, the antioxidant is a mixture of antioxidant 3114 and antioxidant 168 in a mass ratio of 1:2.

[0013] Furthermore, the interface compatibilizer is a polar monomer-grafted polyolefin polymer; preferably, it is selected from one or more of maleic anhydride-grafted polypropylene (PP-g-MAH), maleic anhydride-grafted polyethylene (PE-g-MAH), or acrylic acid-grafted polypropylene (PP-g-AA), or a mixture thereof.

[0014] Furthermore, the other additives are selected from one or more of lubricants, dispersants, nucleating agents, antistatic agents, colorants, or weathering agents, or mixtures thereof.

[0015] A method for preparing a bio-based modified fly ash microsphere composite polypropylene material includes the following steps: S1, fly ash microspheres were activated with alkaline solution and then grafted with vegetable oil-derived modifier in liquid phase to obtain bio-based modified fly ash microspheres. S2, add polypropylene, bio-based modified fly ash microspheres, interface compatibilizer and other additives into a high-speed mixer according to the ratio, dry mix for 3~5 min to obtain the mixture; S3. The mixture is fed into a twin-screw extruder for melt extrusion, cold cutting and granulation to obtain composite masterbatch. The process parameters of the twin-screw extruder are: zone 1 temperature 150~180 ℃, zone 2 temperature 150~180 ℃, zone 3 temperature 150~180 ℃, zone 4 temperature 150~180 ℃; main screw speed 5~30 r / min, feed speed 5~30 r / min.

[0016] Furthermore, the obtained composite masterbatch is dried and then injection molded. The injection molding process parameters are: barrel temperature 190~230 ℃, injection pressure 50~100 MPa, holding pressure 30~80 MPa, mold temperature 30~60 ℃, and cooling time 15~40 s.

[0017] Beneficial effects: This invention utilizes the long fatty chains of vegetable oil derivatives to generate an elastic coating layer in situ on the surface of rigid fly ash microspheres (such as...). Figure 4 a~ Figure 4 As shown in b), this interface can promote the uniform dispersion of powders applied to polypropylene systems (e.g., Figure 4 (as shown in c), it can absorb impact energy to achieve in-situ toughening of the interface, thus solving the problem of the contradiction between rigidity and toughness.

[0018] This invention utilizes bio-based modified fly ash microspheres to composite polypropylene. One end of the microspheres is covalently grafted with a plant oil-derived modifier, while the other end is deeply embedded in the polypropylene matrix to generate physical entanglement. This not only completely solves the problems of powder agglomeration and interface defects, but also achieves in-situ toughening of the material.

[0019] The bio-based modified fly ash microsphere composite polypropylene material of this invention has a masterbatch melt flow rate (230 ℃, 2.16 kg) >10.5 g / 10min; the flexural strength of the molded specimens is 28-34MPa, the flexural modulus is 1250-1400MPa, and the impact performance data is concentrated in 46-54kJ / m2, showing excellent toughening modification effect and good impact resistance.

[0020] This invention replaces traditional petrochemical coupling agents with natural bio-based reagents, achieving a synergistic effect of zero VOC emissions and cost reduction and efficiency improvement, which is highly in line with the orientation of high-value utilization and green low-carbon development of solid waste. This solution not only significantly reduces the cost of polypropylene composite materials, but also effectively alleviates the ecological pressure of fly ash storage, achieving a high degree of unity between ecological and economic benefits, and opening up a new way for the high-value and large-scale comprehensive utilization of bulk solid waste. Attached Figure Description

[0021] Figure 1 The tensile strength trend graphs are for the materials prepared in Examples 1-3 and Comparative Examples 1-4.

[0022] Figure 2 The impact strength trend graphs are for the materials prepared in Examples 1-3 and Comparative Examples 1-4.

[0023] Figure 3 The graph shows the bending strength trend of the materials prepared in Examples 1-3 and Comparative Examples 1-4.

[0024] Figure 4 fly ash microspheres ( Figure 4 a: 2μm), bio-based modified fly ash microspheres ( Figure 4 b: 2μm), bio-based modified fly ash microsphere composite polypropylene material ( Figure 4 Electron micrographs comparing the two (c: 10 μm). Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0026] A bio-based modified fly ash microsphere composite polypropylene material, comprising the following components by weight percentage:

[0027] The above table is denoted as Table 1, where: The polypropylene (55%~75%) is homopolymer polypropylene or block copolymer polypropylene; the melt flow rate is 2~60 g / 10 min under conditions of 230℃ and 2.16 kg load. Further, the homopolymer polypropylene has a crystallinity of over 70% and an isotacticity of 99~100%; the block copolymer polypropylene uses ethylene as its comonomer, with a repeating molar content of 4~10% for ethylene monomers.

[0028] The fly ash microspheres (15%~35%) have a relative density of 2.3~2.4 g / cm³. 3 It is a grayish-white powder with an average particle size of 1 to 10 micrometers. Its main components are SiO2 and Al2O3, with the total amount of the two exceeding 60%.

[0029] The plant oil-derived modifier (1%~4%) is any one of cashew phenol, epoxidized linseed oil or epoxidized soybean oil.

[0030] The antioxidant (0.1%~0.5%) is selected from one or more of hindered phenolic antioxidants, phosphite antioxidants or thioester antioxidants, or a mixture thereof.

[0031] The interface compatibilizer (4%~13%) comprises a polyolefin polymer grafted with a polar monomer; preferably, it is selected from one or more of maleic anhydride-grafted polypropylene (PP-g-MAH), maleic anhydride-grafted polyethylene (PE-g-MAH), or acrylic acid-grafted polypropylene (PP-g-AA) and mixture thereof.

[0032] The other additives (0.1%~1%) are selected from one or more of lubricants, dispersants, nucleating agents, antistatic agents, colorants, or weathering agents. Commonly used reagents or conventional formulations are employed, and the additives are selected according to the required function. The embodiments in this invention use 0.5% stearic acid as an example.

[0033] The preparation method of the above-mentioned bio-based modified fly ash microsphere composite polypropylene material comprises the following steps: Step 1, Bio-based Modified Fly Ash Microspheres: Weigh 15%–35% fly ash according to the weight percentages in Table 1. Place the fly ash microspheres in an alkaline solution with a concentration of 1–3 mol / L and stir at a constant temperature of 60°C–80°C for 2–4 hours. After the reaction is complete, filter the resulting suspension and wash it with deionized water until the filtrate is neutral. Then, place it in a drying oven at 110°C–120°C to dehydrate and dry, obtaining activated fly ash microspheres. Preferably, the alkaline solution is an aqueous solution of sodium hydroxide (NaOH). This step aims to expose a large number of free silicon / aluminum hydroxyl groups on the surface of the powder, providing sufficient active sites for subsequent chemical grafting.

[0034] Weigh 1% to 4% of the vegetable oil-derived modifier according to the weight percentages in Table 1, dissolve it in anhydrous ethanol at a mass of 5 to 10 times that of the vegetable oil-derived modifier, and disperse it by ultrasonication to prepare a homogeneous modifier solution. Preferably, the vegetable oil-derived modifier is any one of cashew nut shell extract, epoxidized linseed oil, or epoxidized soybean oil.

[0035] Activated fly ash microspheres were added to a reactor equipped with a reflux condenser, and anhydrous ethanol was added to disperse the mixture. The prepared modifier solution was then slowly added dropwise while stirring. After the addition was complete, the mixture was refluxed at 70℃~80℃ and 500~800 rpm for 4~6 hours. Through this step, the epoxy groups in the vegetable oil-derived modifier underwent ring-opening, forming a stable covalent ether network with the hydroxyl groups on the surface of the fly ash microspheres. After the reaction, the mixture was filtered under reduced pressure while hot. The resulting filter cake was washed repeatedly with anhydrous ethanol 3~5 times, and then dried in a vacuum drying oven at 80℃~100℃ for 8~12 hours. After complete drying, the mixture was ground and sieved to obtain bio-based modified fly ash microspheres. Figure 4 a~ Figure 4 As shown in electron microscopy image b, the surface of the microspheres changes from a smooth state to an encapsulated state. Preferably, the washing step aims to completely remove free vegetable oil molecules that are physically adsorbed on the powder surface, avoiding excessive plasticization and mechanical degradation of the resin matrix during subsequent compounding.

[0036] Step 2: Weigh the remaining components according to the weight percentages in Table 1, and dry mix them with the bio-based modified fly ash microspheres obtained in Step 1 in a high-speed mixer for 3-5 minutes.

[0037] Step 3: Place the mixture obtained in Step 2 into a micro twin-screw extruder for small-scale testing, and then melt extrude and granulate it. The process parameters are set as follows: Zone 1 150~180 ℃, Zone 2 150~180 ℃, Zone 3 150~180 ℃, Zone 4 150~180 ℃; the main screw speed is 5~30 r / min, and the feed speed is 5~30 r / min.

[0038] Step 4: After the masterbatch dried in Step 3 is melted and plasticized, it is injected into the mold cavity. After holding pressure, cooling and shaping, and demolding, the injection molded product of bio-based modified fly ash microsphere composite polypropylene material is obtained. The process parameters of the injection molding machine are set as follows: barrel temperature 190~230 ℃, injection pressure 50~100 MPa, holding pressure 30~80 MPa, mold temperature 30~60 ℃, and cooling time 15~40 seconds.

[0039] The bio-based modified fly ash microsphere composite polypropylene material obtained by the above preparation method was tested and found to have the following properties: flexural strength ≥ 28 MPa, flexural modulus ≥ 1250 MPa, and unnotched impact strength ≥ 46 kJ / m. 2 .

[0040] The bio-based modified fly ash microsphere composite polypropylene material obtained above has an irreplaceable and important position in automobile manufacturing, home appliance casings, pipes and packaging and other fields.

[0041] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0042] Reagents used in the components involved: Polypropylene is homopolymer polypropylene with a melt flow rate of 10.5 g / 10 min. Fly ash microspheres with a relative density of 2.4 g / cm³. 3 The average particle size was 4.6 μm. Epoxidized linseed oil (ELO, industrial grade, epoxy value ≥8.0%) was purchased from Zhejiang Jiaao Environmental Protection New Energy Co., Ltd.; epoxidized soybean oil (ESO, industrial grade, epoxy value ≥6.0%) was purchased from Hebei Haipuri Fine Chemical Co., Ltd.; cardanol (model NX-2026, high purity) was purchased from Cardolite Chemical Co., Ltd. Silane coupling agent KH550 (chemical name γ-aminopropyltriethoxysilane, abbreviated as APTES, model KBE-903) was purchased from Shin-Etsu Chemical Co., Ltd., Japan. The primary antioxidant 3114 was manufactured by BASF, with the trade name Irganox 3114 and chemical name 3,5-di-tert-butyl-4-hydroxybenzyl phosphate diethyl ester; the secondary antioxidant 168 was also manufactured by BASF, with the trade name Irgafos 168 and chemical name tris(2,4-di-tert-butylphenyl) phosphite. Maleic anhydride-grafted polypropylene (abbreviated as PP-g-MAH, model CMG5904) was purchased from Fineblend Polymer Materials Co., Ltd.

[0043] Example 1 This embodiment provides a bio-based modified fly ash microsphere composite polypropylene material, the components of which include: 66.2% polypropylene, 25% fly ash microspheres, 1.5% vegetable oil-derived modifier (epoxidized linseed oil), 0.1% antioxidant 3114, 0.2% antioxidant 168, 7.5% interface compatibilizer (PP-g-MAH) and 0.5% stearic acid.

[0044] According to the above component ratio, 250g of fly ash microspheres were weighed, activated in sodium hydroxide solution, dried, and placed in a reaction vessel. Then, an ethanol solution containing 15g of epoxidized linseed oil (epoxidized linseed oil: anhydrous ethanol = 1:7.5) was added, and the mixture was refluxed at 70~80 ℃ for 4~6 hours. The resulting product was hot-filtered, washed with anhydrous ethanol, and vacuum-dried at 80~100 ℃. After grinding and sieving, the surface covalently grafted bio-based modified fly ash microspheres were obtained.

[0045] Bio-based modified fly ash microspheres are dry-mixed with other raw materials (weighed according to the formula) for 3-5 minutes and then fed into a twin-screw extruder (temperature in each zone 150-180℃, speed 5-30r / min) for melt extrusion granulation. The resulting masterbatch is dried and placed in an injection molding machine (barrel temperature 190-230℃, injection and holding pressure 30-100 MPa, mold temperature 30-60℃). After injection molding and 15-40 seconds of cooling and demolding, a sample of bio-based modified fly ash microsphere composite polypropylene product is obtained.

[0046] Example 2 This embodiment provides a bio-based modified fly ash microsphere composite polypropylene material, the components of which include: 55.7% polypropylene, 35% fly ash microspheres, 2.0% vegetable oil-derived modifier (epoxidized soybean oil), 0.1% antioxidant 3114, 0.2% antioxidant 168, 6.5% interface compatibilizer (PP-g-MAH) and 0.5% stearic acid.

[0047] According to the above component ratio, 350g of fly ash microspheres were weighed, activated in sodium hydroxide solution, dried, and placed in a reaction vessel. Then, an ethanol solution containing 20g of epoxidized soybean oil (epoxidized soybean oil: anhydrous ethanol = 1:10) was added, and the reaction was carried out in the reaction vessel at a constant temperature of 70~80 ℃ for 4~6 hours. The obtained product was hot-filtered, washed with anhydrous ethanol, and vacuum dried at 80~100 ℃. After grinding and sieving, the surface covalently grafted bio-based modified fly ash microspheres were obtained.

[0048] Bio-based modified fly ash microspheres are dry-mixed with other raw materials (weighed according to the formula) for 3-5 minutes and then fed into a twin-screw extruder (temperature in each zone 150-180℃, speed 5-30r / min) for melt extrusion granulation. The resulting masterbatch is dried and placed in an injection molding machine (barrel temperature 190-230℃, injection and holding pressure 30-100 MPa, mold temperature 30-60℃). After injection molding and 15-40 seconds of cooling and demolding, a sample of bio-based modified fly ash microsphere composite polypropylene product is obtained.

[0049] Example 3 This embodiment provides a bio-based modified fly ash microsphere composite polypropylene material, the components of which include: 72.2% polypropylene, 15% fly ash microspheres, 1.0% vegetable oil-derived modifier (cashew phenol), 0.1% antioxidant 3114, 0.2% antioxidant 168, 11% interface compatibilizer (PP-g-MAH) and 0.5% stearic acid.

[0050] According to the above component ratio, 150g of fly ash microspheres were weighed, activated in sodium hydroxide solution, dried, and placed in a reaction vessel. Then, an ethanol solution containing 10g of cashew phenol (cashew phenol: anhydrous ethanol = 1:5) was added, and the mixture was refluxed at 70-80 ℃ for 4-6 hours. The resulting product was then hot-filtered, washed with anhydrous ethanol, and vacuum-dried at 80-100 ℃. After grinding and sieving, the surface covalently grafted bio-based modified fly ash microspheres were obtained.

[0051] Bio-based modified fly ash microspheres are dry-mixed with other raw materials (weighed according to the formula) for 3-5 minutes and then fed into a twin-screw extruder (temperature in each zone 150-180℃, speed 5-30r / min) for melt extrusion granulation. The resulting masterbatch is dried and placed in an injection molding machine (barrel temperature 190-230℃, injection and holding pressure 30-100 MPa, mold temperature 30-60℃). After injection molding and 15-40 seconds of cooling and demolding, a sample of bio-based modified fly ash microsphere composite polypropylene product is obtained.

[0052] Comparative Example 1 (without vegetable oil-derived modifiers) This comparative example provides an unmodified fly ash microsphere composite polypropylene material, specifically comprising: 67.7% polypropylene, 25% unmodified fly ash microspheres, 0.1% antioxidant 3114, 0.2% antioxidant 168, 6.5% interface compatibilizer (PP-g-MAH), and 0.5% stearic acid. The preparation method does not involve any modification steps and is otherwise the same as the above examples.

[0053] Comparative Example 2 (Silane Coupling Agent Modified Fly Ash Microspheres) This comparative example provides a composite polypropylene material modified with a silane coupling agent using fly ash microspheres, specifically comprising: 66.2% polypropylene, 25% fly ash microspheres, 1.5% silane coupling agent (KH550), 0.1% antioxidant 3114, 0.2% antioxidant 168, 6.5% interface compatibilizer (PP-g-MAH), and 0.5% stearic acid. The preparation method is described, wherein the modification of the fly ash microspheres with the silane coupling agent is a conventional technique, and the other steps are the same as in the above-described embodiment.

[0054] Comparative Example 3 (Low Interfacial Compatibilizer) This comparative example provides a composite material comprising: 71.2% polypropylene, 25% fly ash microspheres, 1.5% vegetable oil-derived modifier (epoxidized linseed oil), 0.1% antioxidant 3114, 0.2% antioxidant 168, 1.5% interfacial compatibilizer (PP-g-MAH), and 0.5% stearic acid. The preparation method is the same as in the above examples.

[0055] Comparative Example 4 (without interfacial compatibilizer) This comparative example provides a composite material comprising: 72.7% polypropylene, 25% fly ash microspheres, 1.5% vegetable oil-derived modifier (epoxidized linseed oil), 0.1% antioxidant 3114, 0.2% antioxidant 168, 0% interfacial compatibilizer (PP-g-MAH), and 0.5% stearic acid. The preparation method is the same as in the above examples.

[0056] Experimental Example The component ratios of the above embodiments and comparative examples are summarized in Table 2.

[0057] Table 2. Component content (mass percentage) of Examples 1-3 and Comparative Examples 1-4

[0058] The above-described embodiments and comparative examples were used to prepare samples, which were then melt-extruded and granulated using a twin-screw extruder. The granulated particles were dried in a forced-air oven at 90-100°C for 2-3 hours, and then the dried particles were injection-molded into samples using an injection molding machine. The resulting specimens were then subjected to performance testing.

[0059] Standards related to performance testing: Tensile properties: According to GB / T9341, the specimen size is 170×10×4mm, and the test rate is 50mm / min; Bending performance: According to GB / T1043.1, the specimen is 80×10×4mm, and the test rate is 2mm / min; Impact strength of simply supported beam: According to GB / T2411, the specimen is 80×10×4mm and the test temperature is 23℃.

[0060] Test results are available Figure 1 Tensile properties, Figure 2 Impact performance Figure 3 Flexural modulus.

[0061] Analysis of performance test results: Depend on Figure 1 The tensile strength trend chart shown demonstrates that Example 1 is significantly superior to Comparative Example 3 (low compatibilizer group) and Comparative Example 4 (no compatibilizer group) in terms of tensile strength data. In Comparative Example 4, due to the lack of an interfacial compatibilizer (PP-g-MAH), severe interfacial delamination occurred between the polar microsphere phase and the non-polar polypropylene matrix, preventing stress transfer and resulting in a precipitous drop in tensile strength. In contrast, the embodiments of this invention, by adding an appropriate amount of high-grafting-rate interfacial compatibilizer, utilize the strong interaction between its polar ends and the bio-based modified layer on the surface of the microspheres, while the non-polar long chains form deep physical entanglement with the polypropylene matrix, successfully constructing a stable stress transfer network.

[0062] Depend on Figure 2 The test results show that the notched impact strength of Examples 1-3 is significantly better than that of Comparative Examples 1 and 2. In Comparative Example 1, due to the lack of surface treatment of the fly ash microspheres, the powder severely agglomerated in the non-polar polypropylene matrix, forming a large number of internal defects and stress concentration points, resulting in obvious brittle fracture characteristics of the material. Although Comparative Example 2 used a traditional silane coupling agent (KH550) for modification and improved dispersibility, the small silane molecules could only form a rigid molecular linkage layer on the surface of the microspheres, which could not effectively absorb external impact energy. In contrast, the embodiments of the present invention introduce a vegetable oil-derived modifier, which, with its long fatty carbon chain, constructs a buffer layer in situ on the surface of the microspheres (such as...). Figure 4 (As shown). When the material is subjected to external impact, this interface layer can undergo synergistic deformation and absorb and dissipate a large amount of impact energy, thereby achieving a breakthrough in-situ toughening effect of the interface.

[0063] Conventional rubber toughening methods in this field often inevitably lead to a significant decrease in material modulus and surface hardness. However, due to... Figure 3 As can be seen, Examples 1-3 of the present invention significantly improved toughness without exhibiting rigid collapse. Due to the introduction of 15%-35% fly ash microspheres with extremely high structural strength, the inorganic phase rich in silica and alumina forms a uniformly distributed rigid skeleton in the matrix, effectively offsetting the stiffness and hardness losses caused by the introduction of the bio-based flexible layer and elastomer, thus achieving a performance balance in the composite material.

[0064] In summary, the present invention overcomes the technical bias of "reinforcement inevitably leads to embrittlement" in traditional inorganic powder-filled polymer systems. The composite materials prepared in the embodiments of the present invention exhibit a stable melt flow rate (230℃, 2.16 kg) of 10.5 g / 10 min or higher, with flexural strength of 28-34 MPa, flexural modulus of 1250-1400 MPa, and impact performance data concentrated in the range of 46-54 kJ / m². 2 .

[0065] All of the above comprehensive performance indicators are met. For example, the garbage can products meet the stringent service standards under complex and extreme outdoor working conditions, realizing the high-value and large-scale disposal and utilization of bulk industrial solid waste, and have outstanding economic benefits and green environmental protection value.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A bio-based modified fly ash microsphere composite polypropylene material, characterized in that, The product comprises the following components by mass percentage: 55%~75% polypropylene, 15%~35% fly ash microspheres, 1%~4% vegetable oil-derived modifier, 0.1%~0.5% antioxidant, 4%~13% interfacial compatibilizer, and 0.1%~1% other additives; wherein the fly ash microspheres are activated by alkaline solution and then liquid-phase grafted with vegetable oil-derived modifier to obtain bio-based modified fly ash microspheres, which are then mixed and dispersed with the remaining components in a polypropylene matrix.

2. The bio-based modified fly ash microsphere composite polypropylene material as described in claim 1, characterized in that, The method for obtaining the aforementioned bio-based modified fly ash microspheres is as follows: Fly ash microspheres were placed in an alkaline solution with a concentration of 1-3 mol / L and stirred at a constant temperature of 60-80℃ for 2-4 hours; then filtered, washed, and dried to obtain activated fly ash microspheres. The vegetable oil-derived modifier was dissolved in 5 to 10 times its weight of anhydrous ethanol and then ultrasonically dispersed to form a modifier solution. The activated fly ash microspheres were added to a reactor equipped with a reflux condenser, and anhydrous ethanol was added to disperse them. The modifier solution was then slowly added dropwise while stirring until complete. The mixture was refluxed at a constant temperature of 70°C to 80°C and a rotation speed of 500 to 800 rpm for 4 to 6 hours. The mixture was then filtered under reduced pressure while hot, and the filter cake was washed repeatedly with anhydrous ethanol 3 to 5 times. It was then vacuum dried at 80 to 100°C for 8 to 12 hours. After complete drying, the mixture was ground and sieved to obtain the bio-based modified fly ash microspheres.

3. A bio-based modified fly ash microsphere composite polypropylene material as described in claim 1 or 2, characterized in that, The plant oil-derived modifier is one or more of epoxidized linseed oil, epoxidized soybean oil, and cashew phenol.

4. A bio-based modified fly ash microsphere composite polypropylene material as described in claim 1 or 2, characterized in that, The fly ash mentioned has a relative density of 2.3–2.4 g / cm³. 3 It is a grayish-white powder with a particle size of 1 to 10 micrometers, preferably with an average particle size of 4.6 micrometers.

5. The bio-based modified fly ash microsphere composite polypropylene material as described in claim 1, characterized in that, The polypropylene is homopolymer polypropylene or block copolymer polypropylene with a melt flow rate of 2~60g / 10min under test conditions of 230 °C and 2.16 kg; preferably, the crystallinity of the homopolymer polypropylene is above 70% and the isotacticity is greater than 99%, and the comonomer of the block copolymer polypropylene is ethylene, with a molar content of 4%~10% of the repeating unit of the ethylene monomer.

6. The bio-based modified fly ash microsphere composite polypropylene material as described in claim 1, characterized in that, The antioxidant is one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants; preferably, the antioxidant is a mixture of antioxidant 3114 and antioxidant 168 in a mass ratio of 1:

2.

7. The bio-based modified fly ash microsphere composite polypropylene material as described in claim 1, characterized in that, The interface compatibilizer is a polar monomer-grafted polyolefin polymer; preferably, it is selected from one or more of maleic anhydride-grafted polypropylene (PP-g-MAH), maleic anhydride-grafted polyethylene (PE-g-MAH), or acrylic acid-grafted polypropylene (PP-g-AA), or a mixture thereof.

8. The bio-based modified fly ash microsphere composite polypropylene material as described in claim 1, characterized in that, The other additives are selected from one or more of the following: lubricants, dispersants, nucleating agents, antistatic agents, colorants, or weathering agents.

9. A method for preparing a bio-based modified fly ash microsphere composite polypropylene material, characterized in that, Using the material according to any one of claims 1 to 8, the method includes the following steps: S1, fly ash microspheres were activated with alkaline solution and then grafted with vegetable oil-derived modifier in liquid phase to obtain bio-based modified fly ash microspheres. S2, add polypropylene, bio-based modified fly ash microspheres, interface compatibilizer and other additives into a high-speed mixer according to the ratio, dry mix for 3~5 min to obtain the mixture; S3. The mixture is fed into a twin-screw extruder for melt extrusion, cold cutting and granulation to obtain composite masterbatch. The process parameters of the twin-screw extruder are: zone 1 temperature 150~180 ℃, zone 2 temperature 150~180 ℃, zone 3 temperature 150~180 ℃, zone 4 temperature 150~180 ℃; main screw speed 5~30 r / min, feed speed 5~30 r / min.

10. An application of a bio-based modified fly ash microsphere composite polypropylene material, characterized in that, The composite masterbatch obtained according to claim 9 is dried and then injection molded to obtain a sample or test piece. The injection molding process parameters are: barrel temperature 190~230 ℃, injection pressure 50~100 MPa, holding pressure 30~80 MPa, mold temperature 30~60 ℃, and cooling time 15~40 s.

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