Modified PPR (pentatricopeptide repeats) pipe with remarkable antibacterial property and preparation method thereof

Abstract

The invention discloses a modified PPR pipe with a remarkable antibacterial function and a preparation method of the modified PPR pipe, and belongs to the technical field of high polymer materials. Through multiple antibacterial mechanisms, the antibacterial effect is remarkably improved, and the broad-spectrum antibacterial property is shown; the prepared graphene oxide has a suitable epoxy functional group, and is modified by isocyanate and ethylenediamine, and the functional group is introduced on the surface, so that the compatibility and dispersion stability of the graphene oxide in a matrix can be improved, more antibacterial active sites are endowed to the graphene oxide, and stacking of the graphene oxide in the processing process is effectively prevented; furthermore, the obvious antibacterial performance is exerted; in addition, the nano zinc oxide is loaded on the porous silicon dioxide carrier, so that the antibacterial components can be released for a long time, and the service life of the pipe is prolonged due to the synergistic interaction effect of the antibacterial components. In addition, when the modified graphene oxide is added into a resin base material, surface groups can be covalently grafted with the resin base material, and the mechanical property of the PPR pipe can be improved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to modified PPR pipes with significant antibacterial properties and their preparation methods. Background Technology

[0002] Random copolymer polypropylene (PPR) pipes have become a preferred choice for building hot and cold water supply and drinking water systems due to their corrosion resistance, smooth inner walls, ease of installation, and good long-term pressure resistance. However, as an organic polymer material, PPR itself does not possess antibacterial properties. During long-term use, especially when transporting drinking water at suitable temperatures, the inner wall of the pipe easily adsorbs organic matter and microorganisms from the water, forming a biofilm that becomes a breeding ground for bacteria such as Escherichia coli, Staphylococcus aureus, and Legionella. This not only affects water quality but also causes scaling on the inner wall of the pipe, reduces flow rate, and shortens the service life of the material.

[0003] To address the aforementioned issues, existing technologies generally employ a blending modification method, adding antibacterial agents to the PPR base material to prepare antibacterial PPR pipes. Commonly used antibacterial agents in existing technologies mainly include: organic antibacterial agents such as quaternary ammonium salts and biguanides. These are characterized by rapid antibacterial action and significant initial effects, but suffer from poor heat resistance, inadequate chemical stability, easy migration and loss, and short shelf life, making them unsuitable for long-term use. Single inorganic antibacterial agents also have limitations, making it difficult to achieve an ideal balance between highly efficient broad-spectrum antibacterial activity, long-term stability, processing adaptability, cost control, and maintaining the original excellent physical properties of PPR pipes.

[0004] Therefore, developing a novel composite antibacterial material that overcomes the shortcomings of single antibacterial agents through the synergistic effect of multiple antibacterial components, and stably and uniformly dispersing it in a PPR matrix to prepare antibacterial PPR pipes with excellent comprehensive performance, has become a pressing technical problem in this field. This invention aims to provide a PPR pipe based on a specific composite antibacterial material and its efficient preparation method, to achieve durable, broad-spectrum, and safe antibacterial properties while ensuring that its mechanical and processing properties meet national standards and usage requirements. Summary of the Invention

[0005] Based on this, in order to solve one of the above-mentioned technical problems, the present invention provides a modified PPR pipe with significant antibacterial properties and a method for preparing the same, the specific technical solution of which is as follows:

[0006] A modified PPR pipe with significant antibacterial properties, the PPR pipe comprising the following raw materials in parts by weight: 100 parts PPR resin base, 0.5-5 parts composite antibacterial material, 1-5 parts compatibilizer, 0.5-5 parts plasticizer, 0.5-5 parts coupling agent, 0.2-1 part antioxidant, and 0.3-1.5 parts lubricant; The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of (4~7):(3~6); The antibacterial component A is modified graphene oxide; the antibacterial component B includes a carrier and nano-zinc oxide loaded on the carrier.

[0007] Furthermore, the method for preparing the modified graphene oxide is as follows: Graphite powder was added to a certain amount of concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 10-15 minutes. KMnO4 was slowly added, and the mixture was reacted at 30-45°C for 1-3 hours. Deionized water was then gradually added, and the mixture was continuously stirred at 90-95°C for 1-3 hours. After cooling to room temperature, H2O2 was added and stirred evenly. The mixture was allowed to stand for 3-5 hours, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 20-30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide.

[0008] Furthermore, the ratio of graphite powder to concentrated sulfuric acid is (1~5) g / 100mL; The ratio of graphite powder, KMnO4 and H2O2 is (1~5) g: (15~20) g: (15~20) mL; The ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is (1~7) g: (10~15) mL: (1~2) g: (5~10) mL.

[0009] Furthermore, the oxygen-containing functional groups in the graphene oxide account for 10% to 50%, and the size is 1 μm to 20 μm.

[0010] Furthermore, the carrier is porous silica, and the average particle size of the porous silica is 20 μm to 100 μm, with a pore volume of 0.5 cm³. 3 / g~10cm 3 / g.

[0011] Furthermore, the loading of the nano zinc oxide is 5% to 20% by weight.

[0012] Furthermore, the compatibilizer is at least one of maleic anhydride, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polyethylene wax, and polyvinyl butyral.

[0013] Furthermore, the plasticizer is at least one of glycerol and polyethylene glycol, and the molecular weight of the glycerol or polyethylene glycol is less than 600.

[0014] In addition, the present invention also provides a method for preparing modified PPR pipe with significant antibacterial properties, the preparation method comprising the following steps: S1. PPR resin base material, composite antibacterial material, compatibilizer, plasticizer, coupling agent, antioxidant and lubricant are premixed at high speed, and then melt-blended and extruded through a twin-screw extruder to obtain a tube blank; S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

[0015] Furthermore, the temperatures of each section of the twin-screw extruder are set as follows: Zone 1 temperature is 150℃~165℃, Zone 2 temperature is 170℃~190℃, Zone 3 temperature is 190℃~210℃, the die head temperature is 200℃~220℃, and the die temperature is 210℃~230℃.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention adds an optimized composite antibacterial material, which significantly enhances the antibacterial effect through multiple antibacterial mechanisms, exhibiting broad-spectrum antibacterial properties. Specifically, the prepared graphene oxide possesses suitable epoxy functional groups, and after modification with isocyanate and ethylenediamine, the introduction of functional groups on the surface not only improves its compatibility and dispersibility stability in resin bases, but also, the introduced isocyanate groups and the primary amine groups in ethylenediamine endow graphene oxide with more antibacterial active sites. The molecular chains grafted onto the graphene oxide also act as molecular spacers, effectively preventing the stacking of graphene oxide during processing, resulting in a higher specific surface area and thus significant antibacterial performance. Furthermore, loading nano-zinc oxide onto a porous silica carrier effectively prevents the aggregation of nanoparticles, ensuring sustained antibacterial release. The synergistic effect of the antibacterial components helps extend the service life of the pipe.

[0017] 2. When the modified graphene oxide of this invention is added to the resin matrix, the surface groups can be covalently grafted with the resin matrix, which also helps to enhance the interfacial bonding force between the modified graphene oxide and the resin matrix, thereby more effectively transferring stress and improving the mechanical properties of PPR pipes.

[0018] 3. Through formula optimization, this invention can produce pipes with both excellent antibacterial and mechanical properties. The preparation process is simple, can be repeatedly scaled up, and has good prospects for industrial production. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] A modified PPR pipe with significant antibacterial properties according to one embodiment of the present invention, wherein the PPR pipe comprises the following raw materials in parts by weight: 100 parts PPR resin base, 0.5-5 parts composite antibacterial material, 1-5 parts compatibilizer, 0.5-5 parts plasticizer, 0.5-5 parts coupling agent, 0.2-1 part antioxidant, and 0.3-1.5 parts lubricant; The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of (4~7):(3~6); The antibacterial component A is modified graphene oxide; the antibacterial component B includes a carrier and nano-zinc oxide loaded on the carrier.

[0022] In one embodiment, the modified graphene oxide is prepared by: Graphite powder was added to a certain amount of concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 10-15 minutes. KMnO4 was slowly added, and the mixture was reacted at 30-45°C for 1-3 hours. Deionized water was then gradually added, and the mixture was continuously stirred at 90-95°C for 1-3 hours. After cooling to room temperature, H2O2 was added and stirred evenly. The mixture was allowed to stand for 3-5 hours, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 20-30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide.

[0023] In one embodiment, the ratio of graphite powder to concentrated sulfuric acid is (1~5) g / 100mL; The ratio of graphite powder, KMnO4 and H2O2 is (1~5) g: (15~20) g: (15~20) mL; The ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is (1~7) g: (10~15) mL: (1~2) g: (5~10) mL.

[0024] In one embodiment, the oxygen-containing functional groups of the graphene oxide account for 10% to 50%, and the size is 1 μm to 20 μm.

[0025] In one embodiment, the carrier is porous silica, and the average particle size of the porous silica is 20 μm to 100 μm, with a pore volume of 0.5 cm³. 3 / g~10cm 3 / g.

[0026] In one embodiment, the loading of the nano-zinc oxide is 5% to 20% by weight. Since the preparation method of antibacterial component B is a conventional technique, it will not be described in detail here. The addition of antibacterial component B in this invention can form a synergistic effect with antibacterial component A, significantly improving antibacterial properties and durability, resulting in more stable overall antibacterial performance.

[0027] In one embodiment, the compatibilizer is at least one of maleic anhydride, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polyethylene wax, and polyvinyl butyral.

[0028] In one embodiment, the plasticizer is at least one of glycerol and polyethylene glycol, and the molecular weight of the glycerol or polyethylene glycol is less than 600.

[0029] In one embodiment, the coupling agent is at least one selected from aminopropyltriethoxysilane, (2,3-epoxypropoxy)propyltrimethoxysilane, methacryloxypropyltrimethoxysilane, mercaptopropyltriethoxysilane, vinyltriethoxysilane, isopropyltris(dioctylphosphoyloxy)titanate, isopropyl tristearate titanate, isopropyl tris(dioctylpyrophosphoyloxy)titanate, and bis(dioctyloxypyrophosphate)ethylene titanate.

[0030] In one embodiment, the antioxidant is at least one of 6-di-tert-butyl-p-cresol, dilauryl thiodipropionate, and tris(2,4-di-tert-butylphenyl) phosphite.

[0031] In one embodiment, the lubricant is at least one of calcium stearate and zinc stearate.

[0032] In addition, the present invention also provides a method for preparing modified PPR pipe with significant antibacterial properties, the preparation method comprising the following steps: S1. PPR resin base material, composite antibacterial material, compatibilizer, plasticizer, coupling agent, antioxidant and lubricant are premixed at high speed, and then melt-blended and extruded through a twin-screw extruder to obtain a tube blank; S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

[0033] In one embodiment, the temperatures of each section of the twin-screw extruder are set as follows: Zone 1 temperature is 150℃~165℃, Zone 2 temperature is 170℃~190℃, Zone 3 temperature is 190℃~210℃, the die head temperature is 200℃~220℃, and the die temperature is 210℃~230℃.

[0034] The above solution, by adding a composite antibacterial agent and optimizing the composition and preparation process of the composite antibacterial agent, can obtain pipes with excellent antibacterial and mechanical properties.

[0035] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments.

[0036] Example 1: A method for preparing modified PPR pipe with significant antibacterial properties includes the following steps: S1. By weight, 100 parts of PPR resin base material, 1 part of composite antibacterial material, 1 part of maleic anhydride grafted polyethylene, 0.5 parts of polyethylene glycol, 1 part of vinyltriethoxysilane, 0.5 parts of 6-di-tert-butyl-p-cresol, and 0.4 parts of calcium stearate are premixed at high speed, then melt-blended and extruded through a twin-screw extruder. The temperature of each section of the twin-screw extruder is set as follows: Zone 1 temperature is 150℃~165℃, Zone 2 temperature is 170℃~190℃, Zone 3 temperature is 190℃~210℃, Die head temperature is 200℃~220℃, and Die temperature is 210℃~230℃ to obtain a tube blank. The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of 7:3; antibacterial component A is modified graphene oxide; antibacterial component B includes porous silica and nano-zinc oxide supported on the porous silica, and the loading of nano-zinc oxide is 10% by weight. The method for preparing the modified graphene oxide is as follows: Prepare the ingredients according to the following proportions: the ratio of graphite powder to concentrated sulfuric acid is 5g / 100mL; the ratio of graphite powder, KMnO4 and H2O2 is 5g:15g:20mL; the ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is 5g:10mL:1g:6mL. Graphite powder was added to concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 15 minutes. KMnO4 was slowly added, and the mixture was reacted at 35°C for 2 hours. Then, an appropriate amount of deionized water was gradually added, and the mixture was continuously stirred at 90°C for 1 hour. After cooling to room temperature, H2O2 was added, and the mixture was stirred evenly. The mixture was allowed to stand for 3 hours, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide with an oxygen-containing functional group ratio of 25%. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide. S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

[0037] Example 2: A method for preparing modified PPR pipe with significant antibacterial properties includes the following steps: S1. By weight, 100 parts of PPR resin base material, 1.1 parts of composite antibacterial material, 1 part of maleic anhydride grafted polyethylene, 0.7 parts of polyethylene glycol, 0.8 parts of vinyltriethoxysilane, 0.4 parts of 6-di-tert-butyl-p-cresol, and 0.5 parts of calcium stearate are premixed at high speed, then melt-blended and extruded through a twin-screw extruder. The temperatures of each section of the twin-screw extruder are set as follows: Zone 1: 150℃~165℃; Zone 2: 170℃~190℃; Zone 3: 190℃~210℃; Die head: 200℃~220℃; and Die: 210℃~230℃, to obtain a tube blank. The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of 6:4; antibacterial component A is modified graphene oxide; antibacterial component B includes porous silica and nano-zinc oxide supported on the porous silica, and the loading of nano-zinc oxide is 10% by weight. The method for preparing the modified graphene oxide is as follows: Prepare the ingredients according to the following proportions: the ratio of graphite powder to concentrated sulfuric acid is 5g / 100mL; the ratio of graphite powder, KMnO4 and H2O2 is 5g:15g:20mL; the ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is 5g:10mL:1g:6mL. Graphite powder was added to concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 15 minutes. KMnO4 was slowly added, and the mixture was reacted at 40°C for 2 hours. Deionized water was then gradually added, and the mixture was continuously stirred at 95°C for 1 hour. After cooling to room temperature, H2O2 was added, and the mixture was stirred evenly. The mixture was allowed to stand for 3 hours, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide with an oxygen-containing functional group ratio of 26%. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide. S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

[0038] Example 3: A method for preparing modified PPR pipe with significant antibacterial properties includes the following steps: S1. By weight, 100 parts of PPR resin base material, 1.2 parts of composite antibacterial material, 1.2 parts of maleic anhydride grafted polyethylene, 0.8 parts of polyethylene glycol, 0.7 parts of vinyltriethoxysilane, 0.3 parts of 6-di-tert-butyl-p-cresol, and 0.5 parts of calcium stearate are premixed at high speed, then melt-blended and extruded through a twin-screw extruder. The temperatures of each section of the twin-screw extruder are set as follows: Zone 1: 150℃~165℃; Zone 2: 170℃~190℃; Zone 3: 190℃~210℃; Die head: 200℃~220℃; and Die: 210℃~230℃, to obtain a tube blank. The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of 5:5; antibacterial component A is modified graphene oxide; antibacterial component B includes porous silica and nano-zinc oxide supported on the porous silica, and the loading of nano-zinc oxide is 10% by weight. The method for preparing the modified graphene oxide is as follows: Prepare the ingredients according to the following proportions: the ratio of graphite powder to concentrated sulfuric acid is 5g / 100mL; the ratio of graphite powder, KMnO4 and H2O2 is 5g:15g:20mL; the ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is 5g:10mL:1g:6mL. Graphite powder was added to concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 15 min. KMnO4 was slowly added, and the mixture was reacted at 45 °C for 1.5 h. Deionized water was then gradually added, and the mixture was continuously stirred at 95 °C for 1 h. After cooling to room temperature, H2O2 was added, and the mixture was stirred evenly. The mixture was allowed to stand for 3 h, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide with an oxygen-containing functional group ratio of 26%. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide. S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

[0039] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that graphite powder was replaced with composite antibacterial material in Comparative Example 1, while the rest is the same as in Example 3.

[0040] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that graphene oxide was used to replace the composite antibacterial material in Comparative Example 2, while the rest is the same as in Example 3.

[0041] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that no isocyanate was added during the modification treatment of graphene oxide in Comparative Example 3, while the rest is the same as in Example 3.

[0042] Comparative Example 4: The difference between Comparative Example 4 and Example 3 is that ethylenediamine was not added during the modification treatment of graphene oxide in Comparative Example 4, but otherwise it was the same as Example 3.

[0043] Comparative Example 5: The difference between Comparative Example 5 and Example 3 is that modified graphene oxide was used to replace the composite antibacterial material in Comparative Example 5 (i.e., no antibacterial component B was added), while the rest is the same as in Example 3.

[0044] Comparative Example 6: The difference between Comparative Example 6 and Example 3 is that nano zinc oxide is used to replace the composite antibacterial material in Comparative Example 6, while the rest is the same as in Example 3.

[0045] Comparative Example 7: Compared with Example 3, Comparative Example 7 differs in that antibacterial component B is used to replace the composite antibacterial material (i.e., antibacterial component A is not added), while the rest is the same as Example 3.

[0046] I. The modified PPR pipe samples prepared in Examples 1-3 and the modified PPR pipe samples prepared in Comparative Examples 1-7 were subjected to mechanical property tests. Tensile strength testing was performed according to GB / T1040.2, and pipe burst pressure testing was performed according to GB / T15560. Pipe specifications are expressed as: d n 20×e n 3.4 The test time was 60-70 seconds to complete the explosion, and the test temperature was 20℃; the results are shown in Table 1 below.

[0047] Table 1: Mechanical Performance Test Results

[0048] Analysis of the data in Table 1 shows that, in Examples 1-3 of this invention, the mechanical strength and burst pressure of the composite antibacterial material after treatment are higher than those of all comparative examples. This indicates that the composite antibacterial material added in this invention does not affect the mechanical properties of PPR material, but rather improves the strength and pressure resistance of PPR pipes to a certain extent. Compared with Example 3, Comparative Examples 1-7 all used different antibacterial components in the experiments. However, the addition of graphite powder, graphene oxide, and nano zinc oxide alone lacked the effect of surface functional groups, resulting in a weaker interfacial bonding than in Example 3, and consequently, poorer pipe strength and pressure resistance than in Example 3.

[0049] II. The modified PPR pipe samples prepared in Examples 1-3 and Comparative Examples 1-7 were subjected to antibacterial performance tests. The antibacterial performance parameters were tested according to B / T31402-2015. The lower the number of viable bacteria, the higher the antibacterial rate. For the antibacterial durability test, the samples after one year of use were tested for antibacterial properties using the same method. The test bacteria were Escherichia coli and Staphylococcus aureus. The antibacterial performance is shown in Table 2.

[0050]

[0051] Analysis of the data in Table 1 shows that the composite antibacterial material added in this invention has a synergistic effect. The initial antibacterial test requires 99.9%, and the antibacterial effect can still reach more than 90% after three months. The modified graphene oxide and porous silica-supported nano-zinc oxide are complementary in antibacterial mechanism. The modified graphene oxide can attack different targets of bacteria by contact destruction and inducing oxidative stress, while the porous silica-supported nano-zinc oxide attacks different targets of bacteria by releasing zinc ions and generating reactive oxygen species, thereby improving the broad spectrum and durability of antibacterial activity. In addition, the modified graphene oxide has better antibacterial activity and stability. Combined with the release mechanism of porous silica-supported nano-zinc oxide, the antibacterial durability can be significantly improved. Compared to Example 3, in Comparative Example 1, graphite powder was used to replace the composite antibacterial material. Since the graphite powder was untreated, the antibacterial activity in the system was extremely low, and the antibacterial performance failed to meet requirements. In Comparative Example 2, graphene oxide was used to replace the composite antibacterial material. Although it initially showed a high antibacterial rate, it exhibited some aggregation during use, resulting in unstable dispersion and insufficient active sites. The antibacterial effect significantly deteriorated over time. In Comparative Example 3, isocyanate was not added during the graphene oxide modification process, and in Comparative Example 4, ethylenediamine was not added. These process defects in Comparative Examples 3 and 4 resulted in inferior antibacterial effects and durability compared to Example 3. This indicates that the addition of isocyanate and ethylenediamine in this invention can effectively graft active functional groups onto graphene oxide, not only... It can prevent the stacking of graphene oxide and significantly improve its compatibility and dispersion stability, thereby exerting efficient and sustained antibacterial activity. In Comparative Example 5, modified graphene oxide was used to replace the composite antibacterial material (i.e., no antibacterial component B was added). Although the modified graphene oxide could also exert a certain antibacterial activity, it lacked the synergistic effect of porous silica-loaded nano-zinc oxide, and its antibacterial durability was not as good as that of Example 3. In Comparative Example 6, nano-zinc oxide was used to replace the composite antibacterial material. Direct use of nano-zinc oxide resulted in a certain degree of agglomeration and failed to achieve the effect of sustained-release antibacterial activity, which significantly affected the antibacterial durability. In Comparative Example 7, antibacterial component B was used to replace the composite antibacterial material (i.e., no antibacterial component A was added). It lacked the synergistic effect of porous silica-loaded nano-zinc oxide, and its antibacterial sustained-release effect was worse than that of Example 3.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A modified PPR pipe with significant antibacterial properties, characterized in that, The PPR pipe comprises the following raw materials in parts by weight: 100 parts PPR resin base, 0.5-5 parts composite antibacterial material, 1-5 parts compatibilizer, 0.5-5 parts plasticizer, 0.5-5 parts coupling agent, 0.2-1 part antioxidant, and 0.3-1.5 parts lubricant; The composite antibacterial material is obtained by mixing antibacterial component A and antibacterial component B in a mass ratio of (4~7):(3~6); The antibacterial component A is modified graphene oxide; the antibacterial component B includes a carrier and nano-zinc oxide loaded on the carrier.

2. The modified PPR pipe with significant antibacterial properties according to claim 1, characterized in that, The method for preparing the modified graphene oxide is as follows: Graphite powder was added to a certain amount of concentrated sulfuric acid and mixed evenly. The mixture was then electromagnetically stirred in an ice-water bath for 10-15 minutes. KMnO4 was slowly added, and the mixture was reacted at 30-45°C for 1-3 hours. Deionized water was then gradually added, and the mixture was continuously stirred at 90-95°C for 1-3 hours. After cooling to room temperature, H2O2 was added and stirred evenly. The mixture was allowed to stand for 3-5 hours, washed with hydrochloric acid and deionized water, centrifuged, and washed again with deionized water until neutral to obtain graphene oxide. The graphene oxide was dispersed in N,N-dimethylamide, and ultrasonic treatment was used to exfoliate the graphene oxide. Then, isocyanate and ethylenediamine were added, and the mixture was magnetically stirred for 20-30 minutes. The mixture was then filtered, washed multiple times with ethanol and deionized water, and dried to obtain modified graphene oxide.

3. The modified PPR pipe with significant antibacterial properties according to claim 2, characterized in that, The ratio of graphite powder to concentrated sulfuric acid added is (1~5) g / 100mL; The ratio of graphite powder, KMnO4 and H2O2 is (1~5) g : (15~20) g : (15~20) mL; The ratio of graphene oxide, N,N-dimethylamide, isocyanate and ethylenediamine is (1~7) g: (10~15) mL: (1~2) g: (5~10) mL.

4. The modified PPR pipe with significant antibacterial properties according to claim 2, characterized in that, The oxygen-containing functional groups in the graphene oxide account for 10% to 50%, and the size is 1 μm to 20 μm.

5. The modified PPR pipe with significant antibacterial properties according to claim 1, characterized in that, The carrier is porous silica, and the average particle size of the porous silica is 20 μm to 100 μm, with a pore volume of 0.5 cm³. 3 / g~10cm 3 / g.

6. The modified PPR pipe with significant antibacterial properties according to claim 5, characterized in that, The loading of the nano zinc oxide is 5% to 20% by weight percentage.

7. The modified PPR pipe with significant antibacterial properties according to claim 1, characterized in that, The compatibilizer is at least one of maleic anhydride, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polyethylene wax, and polyvinyl butyral.

8. The modified PPR pipe with significant antibacterial properties according to claim 1, characterized in that, The plasticizer is at least one of glycerol and polyethylene glycol, and the molecular weight of glycerol or polyethylene glycol is less than 600.

9. A method for preparing a modified PPR pipe with significant antibacterial properties, characterized in that, The preparation method is used to prepare PPR pipes made of the composite antibacterial material as described in claims 1-8, and the preparation method includes the following steps: S1. PPR resin base material, composite antibacterial material, compatibilizer, plasticizer, coupling agent, antioxidant and lubricant are premixed at high speed, and then melt-blended and extruded through a twin-screw extruder to obtain a tube blank; S2. The tube blank is sized, cooled, drawn and cut to obtain the modified PPR pipe with significant antibacterial properties.

10. The preparation method according to claim 9, characterized in that, The temperature settings for each section of the twin-screw extruder are as follows: Zone 1: 150℃~165℃; Zone 2: 170℃~190℃; Zone 3: 190℃~210℃; Die head: 200℃~220℃; and Die: 210℃~230℃.

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