Bio-based flame-retardant antibacterial high polymer material and preparation method thereof
Through multi-component synergistic design, the problems of decreased mechanical properties and insufficient thermal stability of polylactic acid caused by bio-based flame retardants were solved, achieving a synergistic improvement in high flame retardant and antibacterial properties and good mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QINGDAO REALM SUPPLY CHAIN TECH CO LTD
- Filing Date
- 2026-03-02
- Publication Date
- 2026-05-15
AI Technical Summary
Existing bio-based flame retardants, when used to improve the flame retardant properties of polylactic acid, result in a significant decrease in its mechanical properties and insufficient thermal stability of its functional components.
A multi-component synergistic design was adopted, consisting of an antibacterial complex, a flame retardant complex, a magnesium phosphate complex supported by montmorillonite, and polytrimethylene carbonate. The quaternary ammonium salt and guanidine salt were uniformly dispersed through a hydroxypropyl distarch phosphate carrier. An expanded carbon layer was formed by combining hydrophobically modified microcrystalline cellulose with phytic acid and melamine cyanurate. The magnesium phosphate complex supported by montmorillonite enhanced the density of the carbon layer, the polytrimethylene carbonate toughened it, a compatibilizer optimized the interfacial compatibility, and a hydrolysis inhibitor inhibited hydrolytic degradation.
It achieves a synergistic balance between flame retardant and antibacterial functions and material mechanical properties, resulting in strong flame retardant and antibacterial properties while maintaining good mechanical properties.
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of polymer flame retardant materials, and more specifically, to a bio-based flame retardant and antibacterial polymer material and its preparation method. Background Technology
[0002] The environmental pressure posed by traditional petroleum-based polymer materials is becoming increasingly prominent, making the development of renewable bio-based alternatives an important direction for the industry. Polylactic acid (PLA), as a renewable and biodegradable green polymer material, has been applied in many fields such as clothing, packaging, home furnishings, medical and health products, agriculture, forestry, and fisheries. However, PLA itself has two significant drawbacks: First, it has a low limiting oxygen index, is flammable, and produces severe dripping during combustion, posing a fire hazard and greatly limiting its application in fields with stringent flame-retardant safety requirements, such as electronics, building interiors, and transportation vehicles; second, it is brittle, has low elongation at break, and poor impact resistance; third, PLA does not possess inherent antibacterial properties, posing biosafety risks when used in scenarios requiring antibacterial protection, such as medical applications, food packaging, and personal hygiene products.
[0003] To improve the flame retardant properties of PLA, existing technologies mainly employ the method of adding flame retardants, including halogen-based, phosphorus-based, nitrogen-based, inorganic metal hydroxides, and various compound systems. Among them, patent application CN120718351A discloses the application of a bio-based flame retardant composition in the preparation of polylactic acid composite materials. The raw material ratio of the polylactic acid composite material is as follows: 100 parts of polylactic acid; 5-25 parts of a bio-based flame retardant composition, wherein the bio-based flame retardant composition includes: phosphorylated chitosan, the viscosity of which is greater than 400 mPa·s, and the degree of substitution (Ds) of the phosphate groups is not less than 0.5; M-EGCG, wherein M is a transition metal element, and M-EGCG is a complex of epigallocatechin gallate and a transition metal ion; wherein the mass ratio of M-EGCG to phosphorylated chitosan is 1:1-5.
[0004] In this technical solution, a bio-based flame retardant composition of phosphorylated chitosan and M-EGCG is used in polylactic acid. As a rigid particle, phosphorylated chitosan has limited compatibility with the PLA matrix and is prone to agglomeration in the PLA matrix, affecting the processing performance and mechanical stability of the material. At the same time, the thermal stability of the M-EGCG complex is relatively poor, and it is prone to decomposition and deactivation during PLA processing and long-term use, affecting the flame retardant synergistic effect. Summary of the Invention
[0005] In order to overcome the technical defects of existing bio-based flame retardants in improving the flame retardant properties of polylactic acid, which lead to a significant decrease in its mechanical properties and insufficient thermal stability of functional components, this application provides a bio-based flame retardant and antibacterial polymer material and its preparation method.
[0006] In a first aspect, this application provides a bio-based flame-retardant and antibacterial polymer material, employing the following technical solution: A bio-based flame-retardant and antibacterial polymer material, the raw materials for which are prepared include the following components: 100 parts by weight of polylactic acid, 5-15 parts by weight of antibacterial compound, 8-20 parts by weight of flame retardant compound, 2-5 parts by weight of magnesium phosphate compound supported on montmorillonite, 1-3 parts by weight of compatibilizer, 0.5-2 parts by weight of hydrolysis inhibitor and 6-8 parts by weight of polytrimethylene carbonate. The antibacterial complex comprises hydroxypropyl distarch phosphate, a quaternary ammonium salt, and a guanidine salt.
[0007] The flame-retardant composite includes hydrophobically modified microcrystalline cellulose, phytic acid or ammonium phytate, and melamine cyanurate.
[0008] In this technical solution, polylactic acid (PLA) is used as the matrix, and hydroxypropyl distarch phosphate in the antibacterial complex serves as a bio-based carrier to achieve uniform dispersion of quaternary ammonium salts and guanidine salts. This ensures the long-lasting antibacterial activity of the antibacterial components and improves the interfacial bonding between the antibacterial components and the PLA matrix through its biocompatibility. The flame-retardant complex is composed of hydrophobically modified microcrystalline cellulose, phytic acid (or ammonium phytate), and melamine cyanurate to form a bio-based intumescent flame-retardant system. The hydrophobically modified microcrystalline cellulose enhances the dispersibility of the flame-retardant components in PLA and their compatibility with the matrix. Phytic acid (or ammonium phytate) serves as the acid source, and melamine cyanurate serves as the gas source. The two components work synergistically to provide carbon source for the hydrophobically modified microcrystalline cellulose, forming a dense char layer during combustion. This effectively blocks heat and smoke transfer, enhancing the material's flame retardant properties. The magnesium-phosphorus composite loaded with montmorillonite is reinforced for char formation through the layered structure of montmorillonite, and also plays a synergistic flame retardant role during combustion. Polytrimethylene carbonate, as a flexible segment, significantly improves the material's toughness, compensating for the increased brittleness caused by the flame retardant. The compatibilizer further optimizes the interfacial compatibility between each component and the polylactic acid matrix, reducing aggregation between components. The hydrolysis inhibitor effectively inhibits the hydrolytic degradation of polylactic acid during processing and use, ensuring the material's long-term performance.
[0009] Preferably, the mass ratio of the hydrophobically modified microcrystalline cellulose, phytic acid or ammonium phytate, and melamine cyanurate is (3~5):(2~3):(1~2).
[0010] Preferably, the polylactic acid has a number-average molecular weight of 80,000 to 150,000.
[0011] Preferably, the number-average molecular weight of the polytrimethylene carbonate is 50,000 to 100,000.
[0012] Preferably, the method for preparing the montmorillonite-supported magnesium-phosphorus composite includes the following steps: S11: Disperse sodium-based montmorillonite in water to prepare a suspension, heat to 60-80℃, add chitosan quaternary ammonium salt, react for 4-6 hours, separate solid and liquid, wash, dry, and pulverize to obtain organically modified montmorillonite. S12: Disperse organically modified montmorillonite in water, add magnesium salt and diammonium hydrogen phosphate, adjust the pH to 9.5~10.0, mix for 2~3 hours, then separate the solid and liquid, wash, and dry to obtain montmorillonite-loaded magnesium phosphate complex.
[0013] Preferably, the mass concentration of the suspension is 3% to 6%.
[0014] Preferably, the mass ratio of sodium montmorillonite, chitosan quaternary ammonium salt, magnesium salt and diammonium hydrogen phosphate is 1:(0.15~0.25):(0.125~0.175):(0.05~0.1).
[0015] Preferably, the chitosan quaternary ammonium salt is hydroxypropyltrimethylammonium chloride chitosan.
[0016] In this technical solution, chitosan quaternary ammonium salt is used to organically modify montmorillonite, increasing the interlayer spacing and improving its compatibility with polylactic acid matrix. Under alkaline conditions, magnesium salt reacts with diammonium hydrogen phosphate to generate magnesium-phosphorus composite precipitates in situ on the surface and between the layers of the organically modified montmorillonite. During combustion, the layered structure of montmorillonite promotes the formation of a dense char layer, magnesium compounds decompose to release water vapor and generate an oxide insulation layer, and phosphorus compounds catalyze the dehydration of the polymer to form char. The synergistic effect of these three factors significantly improves the flame retardant properties and thermal stability of the material.
[0017] Preferably, the method for preparing the hydrophobically modified microcrystalline cellulose includes the following steps: Under a nitrogen atmosphere, microcrystalline cellulose was dispersed in N,N-dimethylformamide, and a catalyst and stearoyl chloride (3%–8% by mass of microcrystalline cellulose) were added. The mixture was heated to 80–100 °C and reacted for 4–6 h. After solid-liquid separation, the mixture was washed and dried to obtain hydrophobically modified microcrystalline cellulose.
[0018] Preferably, the catalyst is pyridine or triethylamine.
[0019] Preferably, the amount of catalyst used is 1% to 2% of the mass of microcrystalline cellulose.
[0020] In this technical solution, stearoyl chloride is used as a modifier. The acyl chloride group in its molecule can undergo esterification with the hydroxyl groups on the surface of microcrystalline cellulose, introducing long-chain alkyl hydrophobic groups onto the microcrystalline cellulose molecular chain. This reduces the hydrophilicity of microcrystalline cellulose, improves its dispersibility and compatibility in the polylactic acid matrix, and avoids its flame retardant effect and material mechanical properties due to hydrophilic aggregation. At the same time, the modified microcrystalline cellulose still retains good biocompatibility and carbon source characteristics. It can work synergistically with phytic acid (or ammonium phytate) and melamine cyanurate to form a dense char layer during combustion, effectively blocking heat and smoke transfer and significantly improving the flame retardant performance of the material.
[0021] Preferably, the compatibilizer comprises glycidyl methacrylate-grafted polyolefin elastomer and maleic anhydride-grafted polylactic acid.
[0022] In this technical solution, maleic anhydride-grafted polylactic acid (PLA-g-MAH) has a molecular structure that is highly similar to that of polylactic acid matrix, which can quickly improve the interfacial compatibility between various functional components and polylactic acid and reduce component aggregation. Glycidyl methacrylate-grafted polyolefin elastomer (POE-g-GMA) can partially bond with the active groups in antibacterial and flame-retardant components through its grafted epoxy groups, further strengthening the interfacial bonding force. At the same time, the POE segments can play a toughening role and work synergistically with polytrimethylene carbonate to alleviate the adverse effects of functional components on the mechanical properties of polylactic acid.
[0023] Preferably, the method for preparing the antibacterial complex includes the following steps: Hydroxypropyl distarch phosphate, quaternary ammonium salt and guanidine salt are added to a mixer, and water of 5% to 10% of the mass of hydroxypropyl distarch phosphate is added. The mixture is mixed evenly, dried and pulverized to obtain an antibacterial complex.
[0024] In this technical solution, hydroxypropyl distarch phosphate serves as an antibacterial carrier. The phosphate groups on its molecular chain can bind with cationic quaternary ammonium salt and guanidine salt antibacterial agents through polar interactions, enhancing the loading strength of the antibacterial agents. Hydroxypropyl distarch phosphate itself is a bio-based component with good biocompatibility with polylactic acid (PLA). Furthermore, its etherification-esterification composite modified structure improves the dispersibility of the antibacterial complex within the PLA matrix. The combination of quaternary ammonium salt and guanidine salt broadens the antibacterial spectrum and enhances the antibacterial durability.
[0025] Preferably, the mass ratio of the hydroxypropyl distarch phosphate, the quaternary ammonium salt, and the guanidine salt is (3~5):(1~3):(1~2).
[0026] Preferably, the quaternary ammonium salt is selected from at least one of dodecyl dimethyl benzyl ammonium chloride and hexadecyl trimethyl ammonium bromide.
[0027] Preferably, the guanidine salt is selected from at least one of polyhexamethylene guanidine hydrochloride and polyhexamethylene guanidine phosphate.
[0028] Preferably, the hydrolysis inhibitor is N,N'-bis(2,6-diisopropylphenyl)carbodiimide.
[0029] In this technical solution, the hydrolysis inhibitor can effectively inhibit the hydrolytic degradation of polylactic acid during processing and use, ensuring the long-term performance of the material.
[0030] Preferably, the raw materials for preparing the bio-based flame-retardant and antibacterial polymer material further include 3-5 parts by weight of organic borate ester.
[0031] Preferably, the organoboroester is selected from at least one of triphenylboronic acid ester and butylboronic acid ester.
[0032] In this technical solution, the addition of organic borate esters can further synergistically improve the flame retardant properties of the material, while improving the processing fluidity of the material, forming a synergistic effect with other flame retardant components, and enhancing the density and stability of the char layer.
[0033] Secondly, this application provides a method for preparing a bio-based flame-retardant and antibacterial polymer material, comprising the following steps: Polylactic acid, antibacterial compound, flame retardant compound, montmorillonite-loaded magnesium phosphate compound, polytrimethylene carbonate, compatibilizer and hydrolysis inhibitor are added to a mixer, mixed evenly, extruded, cooled and granulated to obtain a bio-based flame retardant and antibacterial polymer material.
[0034] Preferably, the extruder parameters used during extrusion are set as follows: feed section 160~165℃, melting section 170~175℃, die head section 175~180℃, and screw speed 200~300r / min.
[0035] Preferably, the preparation method further includes the step of adding an organoboroate ester after adding polytrimethylene carbonate.
[0036] In summary, this application has the following beneficial effects: This application achieves a synergistic balance between flame retardant and antibacterial functions and the material's mechanical properties through a multi-component synergistic design of an antibacterial complex, a flame retardant complex, a montmorillonite-supported magnesium phosphate complex, and polytrimethylene carbonate. Specifically, the antibacterial complex utilizes a hydroxypropyl distarch phosphate carrier to achieve uniform dispersion of quaternary ammonium salts and guanidine salts, imparting a high antibacterial rate to the material. The flame retardant complex, composed of hydrophobically modified microcrystalline cellulose, phytic acid, and melamine cyanurate, forms an expanded char layer. The montmorillonite-supported magnesium phosphate complex significantly enhances the density and thermal stability of the char layer. Polytrimethylene carbonate provides toughening compensation, effectively overcoming the defect of decreased mechanical properties caused by flame retardant modification. The synergistic effect of each component allows the material to maintain good mechanical properties while achieving strong flame retardant and antibacterial properties. Detailed Implementation
[0037] The present application will be further described in detail below with reference to the embodiments.
[0038] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.
[0039] The number-average molecular weight distribution of polylactic acid is 80,000 to 150,000; the number-average molecular weight distribution of polytrimethylene carbonate is 50,000 to 100,000.
[0040] Preparation Examples 1-3: Magnesium Phosphate Composites Supported by Montmorillonite Preparation Example 1 The preparation method of the montmorillonite-supported magnesium-phosphorus composite in this preparation example includes the following steps: S11: Disperse 200g of sodium montmorillonite evenly in deionized water to prepare a suspension with a mass concentration of 5%. Heat the suspension to 70℃, add 30g of hydroxypropyltrimethylammonium chloride chitosan, react for 5h, centrifuge, wash three times with deionized water, dry at 60℃, pulverize, and pass through a 100-mesh sieve to obtain organic modified montmorillonite. S12: Organically modified montmorillonite was uniformly dispersed in deionized water to prepare a suspension with a mass concentration of 8%. Then, 25g of magnesium chloride hexahydrate and 10g of diammonium hydrogen phosphate were added. The pH was adjusted to 9.5 with 10% ammonia water. After stirring for 2.5h, the mixture was centrifuged, washed with deionized water until neutral, and dried at 60℃ to obtain the magnesium-phosphorus complex supported on montmorillonite.
[0041] Preparation Example 2 The preparation method of the montmorillonite-supported magnesium-phosphorus composite in this preparation example includes the following steps: S11: Disperse 200g of sodium montmorillonite evenly in deionized water to prepare a suspension with a mass concentration of 3%. Heat the suspension to 60℃, add 50g of hydroxypropyltrimethylammonium chloride chitosan, react for 6h, centrifuge, wash three times with deionized water, dry at 60℃, pulverize, and pass through a 100-mesh sieve to obtain organic modified montmorillonite. S12: Organically modified montmorillonite was uniformly dispersed in deionized water to prepare a suspension with a mass concentration of 8%. Then, 35g of magnesium chloride hexahydrate and 20g of diammonium hydrogen phosphate were added. The pH was adjusted to 10.0 with 10% ammonia water. After stirring for 3 hours, the mixture was centrifuged, washed with deionized water until neutral, and dried at 60℃ to obtain the magnesium-phosphorus complex supported on montmorillonite.
[0042] Preparation Example 3 The preparation method of the montmorillonite-supported magnesium-phosphorus composite in this preparation example includes the following steps: S11: Disperse 200g of sodium montmorillonite evenly in deionized water to prepare a suspension with a mass concentration of 6%. Heat the suspension to 80℃, add 40g of hydroxypropyltrimethylammonium chloride chitosan, react for 4h, centrifuge, wash three times with deionized water, dry at 60℃, pulverize, and pass through a 100-mesh sieve to obtain organic modified montmorillonite. S12: Organically modified montmorillonite was uniformly dispersed in deionized water to prepare a suspension with a mass concentration of 8%. Then, 30g of magnesium chloride hexahydrate and 15g of diammonium hydrogen phosphate were added. The pH was adjusted to 10.0 with 10% ammonia water. After stirring for 2 hours, the mixture was centrifuged, washed with deionized water until neutral, and dried at 60℃ to obtain the magnesium-phosphorus complex supported on montmorillonite.
[0043] Preparation Examples 4-6: Hydrophobically Modified Microcrystalline Cellulose Preparation Example 4 The preparation method of hydrophobically modified microcrystalline cellulose in this example includes the following steps: Under a nitrogen atmosphere, 1 kg of microcrystalline cellulose was uniformly dispersed in N,N-dimethylformamide (which was dehydrated by molecular sieve before use) to prepare a suspension with a mass concentration of about 10%. 10 g of pyridine and 30 g of stearoyl chloride were added, the temperature was raised to 80 °C, and the reaction was carried out for 6 h. The mixture was then centrifuged, and the product was washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 24 h to obtain hydrophobically modified microcrystalline cellulose.
[0044] Preparation Example 5 The preparation method of hydrophobically modified microcrystalline cellulose in this example includes the following steps: Under a nitrogen atmosphere, 1 kg of microcrystalline cellulose was uniformly dispersed in N,N-dimethylformamide (which was dehydrated by molecular sieve before use) to prepare a suspension with a mass concentration of about 10%. 15 g of triethylamine and 50 g of stearoyl chloride were added, the temperature was raised to 90 °C, and the reaction was carried out for 5 h. The mixture was then centrifuged, and the product was washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 24 h to obtain hydrophobically modified microcrystalline cellulose.
[0045] Preparation Example 6 The preparation method of hydrophobically modified microcrystalline cellulose in this example includes the following steps: Under a nitrogen atmosphere, 1 kg of microcrystalline cellulose was uniformly dispersed in N,N-dimethylformamide (which was dehydrated by molecular sieve before use) to prepare a suspension with a mass concentration of about 10%. 20 g of triethylamine and 80 g of stearoyl chloride were added, the temperature was raised to 100 °C, and the reaction was carried out for 4 h. The mixture was then centrifuged, and the product was washed three times with anhydrous ethanol and dried under vacuum at 60 °C for 24 h to obtain hydrophobically modified microcrystalline cellulose.
[0046] Example 1 The preparation method of the bio-based flame-retardant and antibacterial polymer material in this embodiment includes the following steps: 2000g of polylactic acid, 100g of antibacterial compound, 160g of flame retardant compound, 40g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 1, 120g of polytrimethylene carbonate, 20g of compatibilizer and 10g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0047] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0048] The preparation method of the antibacterial complex includes the following steps: Add 60g of hydroxypropyl distarch phosphate, 20g of dodecyl dimethyl benzyl ammonium chloride and 20g of polyhexamethylene guanidine hydrochloride to a high-speed mixer, spray with 5% of the mass of hydroxypropyl distarch phosphate deionized water, mix evenly at 800r / min, dry at 60℃, and pulverize to obtain an antibacterial complex.
[0049] The flame retardant composite was prepared using 80g of hydrophobically modified microcrystalline cellulose, 53g of phytic acid, and 27g of melamine cyanurate, as described in Example 4.
[0050] The compatibilizers are 5g of glycidyl methacrylate-grafted polyolefin elastomer and 15g of maleic anhydride-grafted polylactic acid.
[0051] The hydrolysis inhibitor is N,N'-bis(2,6-diisopropylphenyl)carbodiimide.
[0052] Example 2 The preparation method of the bio-based flame-retardant and antibacterial polymer material in this embodiment includes the following steps: 2000g of polylactic acid, 300g of antibacterial compound, 400g of flame retardant compound, 100g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 2, 160g of polytrimethylene carbonate, 60g of compatibilizer, and 40g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried, and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0053] Twin-screw extruder process parameters settings: feed section 165℃, melt section 175℃, die head section 180℃, screw speed 300r / min.
[0054] The preparation method of the antibacterial complex includes the following steps: 150g of hydroxypropyl distarch phosphate, 50g of dodecyl dimethyl benzyl ammonium chloride, 40g of hexadecyl trimethyl ammonium bromide, 30g of polyhexamethylene guanidine hydrochloride, and 30g of polyhexamethylene guanidine phosphate were added to a high-speed mixer. Deionized water accounting for 10% of the mass of hydroxypropyl distarch phosphate was sprayed on the mixture. The mixture was mixed evenly at 800r / min, dried at 60℃, and pulverized to obtain an antibacterial complex.
[0055] The flame retardant composite was prepared using 200g of hydrophobically modified microcrystalline cellulose, 120g of phytic acid, and 80g of melamine cyanurate, as described in Example 5.
[0056] The compatibilizers are 20g of glycidyl methacrylate-grafted polyolefin elastomer and 40g of maleic anhydride-grafted polylactic acid.
[0057] The hydrolysis inhibitor is N,N'-bis(2,6-diisopropylphenyl)carbodiimide.
[0058] Example 3 The preparation method of the bio-based flame-retardant and antibacterial polymer material in this embodiment includes the following steps: 2000g of polylactic acid, 200g of antibacterial compound, 270g of flame retardant compound, 65g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 3, 140g of polytrimethylene carbonate, 45g of compatibilizer and 30g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0059] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0060] The preparation method of the antibacterial complex includes the following steps: 107g of hydroxypropyl distarch phosphate, 33g of dodecyl dimethyl benzyl ammonium chloride, 20g of hexadecyl trimethyl ammonium bromide, 25g of polyhexamethylene guanidine hydrochloride, and 15g of polyhexamethylene guanidine phosphate were added to a high-speed mixer, and 8% of the mass of hydroxypropyl distarch phosphate was sprayed with deionized water. The mixture was mixed evenly at 800r / min, dried at 60℃, and pulverized to obtain the antibacterial complex.
[0061] The flame retardant composite was prepared using 135g of hydrophobically modified microcrystalline cellulose, 85g of ammonium phytate, and 50g of melamine cyanurate, as described in Example 6.
[0062] The compatibilizers are 10g of glycidyl methacrylate-grafted polyolefin elastomer and 35g of maleic anhydride-grafted polylactic acid.
[0063] The hydrolysis inhibitor is N,N'-bis(2,6-diisopropylphenyl)carbodiimide.
[0064] Example 4 The difference between this embodiment and embodiment 3 is as follows: The preparation method of the bio-based flame-retardant and antibacterial polymer material in this embodiment includes the following steps: 2000g of polylactic acid, 200g of antibacterial compound, 270g of flame retardant compound, 65g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 2, 140g of polytrimethylene carbonate, 60g of triphenylboronic acid ester, 45g of compatibilizer, and 30g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried, and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0065] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0066] Everything else is the same as in Example 3.
[0067] Example 5 The difference between this embodiment and embodiment 3 is as follows: The preparation method of the bio-based flame-retardant and antibacterial polymer material in this embodiment includes the following steps: 2000g of polylactic acid, 200g of antibacterial compound, 270g of flame retardant compound, 65g of montmorillonite-supported magnesium phosphate compound from Preparation Example 2, 140g of polytrimethylene carbonate, 60g of triphenylboronic acid, 40g of butylboronic acid, 45g of compatibilizer, and 30g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried, and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0068] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0069] Everything else is the same as in Example 3.
[0070] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: The preparation method of the bio-based flame-retardant and antibacterial polymer material in this comparative example includes the following steps: 2000g of polylactic acid, 100g of antibacterial compound, 160g of flame retardant compound, 40g of organically modified montmorillonite, 120g of polytrimethylene carbonate, 20g of compatibilizer and 10g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0071] Everything else is the same as in Example 1.
[0072] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: No polytrimethylene carbonate was added; Everything else is the same as in Example 1.
[0073] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: The preparation method of the bio-based flame-retardant and antibacterial polymer material in this comparative example includes the following steps: 2000g of polylactic acid, 40g of antibacterial compound, 160g of flame retardant compound, 40g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 1, 120g of polytrimethylene carbonate, 20g of compatibilizer, and 10g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried, and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0074] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0075] The antibacterial complex consists of 20g of dodecyl dimethyl benzyl ammonium chloride and 20g of polyhexamethylene guanidine hydrochloride.
[0076] Everything else is the same as in Example 1.
[0077] Comparative Example 4 The difference between this comparative example and Example 1 is as follows: The preparation method of the bio-based flame-retardant and antibacterial polymer material in this comparative example includes the following steps: 2000g of polylactic acid, 100g of antibacterial compound, 160g of flame retardant compound, 40g of montmorillonite-loaded magnesium phosphate compound from Preparation Example 1, 120g of polytrimethylene carbonate, 20g of compatibilizer and 10g of hydrolysis inhibitor were added to a high-speed mixer and mixed at 800r / min for 10min. The mixture was then transferred to a twin-screw extruder for extrusion, water-cooled, air-dried and granulated to obtain a bio-based flame-retardant and antibacterial polymer material.
[0078] Twin-screw extruder process parameters settings: feed section 160℃, melting section 170℃, die head section 175℃, screw speed 200r / min.
[0079] The flame retardant compound consists of 80g of microcrystalline cellulose, 53g of phytic acid, and 27g of melamine cyanurate.
[0080] Everything else is the same as in Example 1.
[0081] Performance testing The bio-based flame-retardant and antibacterial polymer materials prepared in Examples 1-5 and Comparative Examples 1-4 were vacuum dried at 80°C for 4 hours, and the following performance tests were conducted, as detailed in Table 1.
[0082] Table 1 Performance test data of bio-based flame-retardant and antibacterial polymer materials in Examples 1-5 and Comparative Examples 1-4
[0083] Compared to Example 1, Comparative Example 1, which used ordinary organic modified montmorillonite instead of montmorillonite-loaded magnesium phosphate composite, showed a decrease in limiting oxygen index and UL-94 rating, as well as a significant reduction in tensile strength and impact strength. This indicates that the montmorillonite-loaded magnesium phosphate composite can effectively improve the flame retardant properties and mechanical reinforcement of the material. Comparative Example 2, which did not contain polytrimethylene carbonate, exhibited flame retardant properties comparable to Example 1, but its impact strength decreased, demonstrating that polytrimethylene carbonate, as a flexible segment, can effectively compensate for the increased brittleness caused by the flame retardant.
[0084] In Comparative Example 3, the antibacterial complex did not use hydroxypropyl distarch phosphate as a carrier, resulting in a decrease in antibacterial rate and a reduction in mechanical properties. This demonstrates that hydroxypropyl distarch phosphate not only serves as an antibacterial carrier to achieve uniform dispersion of quaternary ammonium salt and guanidine salt, but also improves interfacial bonding through its biocompatibility, playing an important role in maintaining the overall performance of the material.
[0085] The flame-retardant composite of Comparative Example 4, which directly uses microcrystalline cellulose, showed a decrease in limiting oxygen index and UL-94 rating, indicating that hydrophobic modification of microcrystalline cellulose can significantly improve its dispersibility and compatibility in polylactic acid matrix, thereby obtaining better flame-retardant and mechanical properties.
[0086] In Examples 1-3, through multi-component synergistic design, the prepared bio-based flame-retardant and antibacterial polymer materials achieved high flame-retardant and antibacterial properties while maintaining good mechanical properties.
[0087] In Examples 3-5, the use of compound organic borate esters with different structures can produce a more significant synergistic effect. The aromatic structure of triphenylboronic acid ester helps to enhance the density of the char layer, while the flexible segments of butylboronic acid ester are more conducive to improving the toughening effect, further enhancing the flame retardant properties and impact strength of the material.
[0088] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A bio-based flame-retardant and antibacterial polymer material, characterized in that, Its preparation raw materials include the following components: 100 parts by weight of polylactic acid, 5-15 parts by weight of antibacterial compound, 8-20 parts by weight of flame retardant compound, 2-5 parts by weight of magnesium phosphate compound supported on montmorillonite, 1-3 parts by weight of compatibilizer, 0.5-2 parts by weight of hydrolysis inhibitor and 6-8 parts by weight of polytrimethylene carbonate. The antibacterial complex comprises hydroxypropyl distarch phosphate, a quaternary ammonium salt, and a guanidine salt. The flame-retardant composite includes hydrophobically modified microcrystalline cellulose, phytic acid or ammonium phytate, and melamine cyanurate.
2. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The mass ratio of the hydrophobically modified microcrystalline cellulose, phytic acid or ammonium phytate, and melamine cyanurate is (3~5):(2~3):(1~2).
3. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The preparation method of the montmorillonite-supported magnesium-phosphorus complex includes the following steps: S11: Disperse sodium-based montmorillonite in water to prepare a suspension, heat to 60-80℃, add chitosan quaternary ammonium salt, react for 4-6 hours, separate solid and liquid, wash, dry, and pulverize to obtain organically modified montmorillonite. S12: Disperse organically modified montmorillonite in water, add magnesium salt and diammonium hydrogen phosphate, adjust the pH to 9.5~10.0, mix for 2~3 hours, then separate the solid and liquid, wash, and dry to obtain montmorillonite-loaded magnesium phosphate complex.
4. The bio-based flame-retardant and antibacterial polymer material according to claim 3, characterized in that, The mass ratio of sodium montmorillonite, chitosan quaternary ammonium salt, magnesium salt and diammonium hydrogen phosphate is 1:(0.15~0.25):(0.125~0.175):(0.05~0.1).
5. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The method for preparing the hydrophobically modified microcrystalline cellulose includes the following steps: Under a nitrogen atmosphere, microcrystalline cellulose was dispersed in N,N-dimethylformamide, and a catalyst and stearoyl chloride (3%–8% by mass of microcrystalline cellulose) were added. The mixture was heated to 80–100 °C and reacted for 4–6 h. After solid-liquid separation, the mixture was washed and dried to obtain hydrophobically modified microcrystalline cellulose.
6. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The method for preparing the antibacterial complex includes the following steps: Hydroxypropyl distarch phosphate, quaternary ammonium salt and guanidine salt are added to a mixer, and water of 5% to 10% of the mass of hydroxypropyl distarch phosphate is added. The mixture is mixed evenly, dried and pulverized to obtain an antibacterial complex.
7. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The hydrolysis inhibitor is N,N'-bis(2,6-diisopropylphenyl)carbodiimide.
8. The bio-based flame-retardant and antibacterial polymer material according to claim 1, characterized in that, The raw materials for preparing the bio-based flame-retardant and antibacterial polymer material also include 3-5 parts by weight of organic borate ester.
9. A method for preparing a bio-based flame-retardant and antibacterial polymeric material as described in any one of claims 1 to 7, characterized in that, The process includes the following steps: adding polylactic acid, antibacterial compound, flame retardant compound, montmorillonite-loaded magnesium phosphate compound, polytrimethylene carbonate, compatibilizer and hydrolysis inhibitor into a mixer, mixing evenly, extruding, cooling, and granulating to obtain a bio-based flame retardant and antibacterial polymer material.
10. The method for preparing the bio-based flame-retardant and antibacterial polymeric material according to claim 9, characterized in that, The addition of polytrimethylene carbonate is followed by the addition of organoboroate.