Preparation method of modified phosphogypsum reinforced polypropylene special material for inspection well
By acid washing and surface activator modification of phosphogypsum, combined with the melt blending process of activator and auxiliary activator, the problems of insufficient strength of polypropylene materials and pollution from phosphogypsum accumulation were solved, realizing the resource utilization of phosphogypsum and improving material performance.
Patent Information
- Application Number
- CN202510783748.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-12
- Publication Date
- 2025-12-09
- Estimated Expiration
- 2045-06-12
AI Technical Summary
Pure polypropylene has low strength and rigidity, limiting its use in applications with high mechanical performance requirements. Meanwhile, the accumulation of phosphogypsum occupies land resources and may pollute the environment. The question of how to achieve the resource utilization of phosphogypsum and its compatibility with polypropylene is a key issue.
Modified phosphogypsum-reinforced polypropylene inspection well material was prepared by acid washing of phosphogypsum, modification with the addition of surface activators, mixing with polypropylene, and then melt-blending the dispersion of activators and auxiliary activators in a twin-screw extruder.
The overall performance of polypropylene inspection well material has been improved, realizing the resource utilization of phosphogypsum, enhancing the mechanical properties of the material, and reducing costs.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the technical field of polypropylene inspection wells, in particular to a preparation method of modified phosphogypsum reinforced polypropylene inspection well special material. BACKGROUND
[0002] Polypropylene (PP) material has been widely used in the field of inspection well manufacturing due to its good comprehensive performance, such as light weight, strong chemical corrosion resistance and excellent processing performance. However, the strength and rigidity of pure PP material are relatively low, which limits its use in some scenarios with high mechanical performance requirements. As a solid waste in the production process of phosphoric acid, phosphogypsum has a huge output. A large amount of phosphogypsum accumulation not only occupies a large amount of land resources, but also may cause pollution to the surrounding environment, such as the heavy metals and soluble phosphorus, fluorine and other pollutants contained therein may penetrate into the soil and groundwater. How to realize the effective resource utilization of phosphogypsum has been one of the research hotspots in the fields of environmental protection and materials.
[0003] After the modification of phosphogypsum, it is added to polypropylene, which is expected to improve the performance of polypropylene inspection well special material while realizing the large-scale consumption of phosphogypsum, and has significant environmental and economic benefits. However, in this process, a series of problems need to be solved, such as the compatibility of phosphogypsum and polypropylene, the dispersibility of phosphogypsum and how to realize the optimization of material performance through reasonable process parameters. SUMMARY
[0004] The purpose of the present application is to provide a preparation method of modified phosphogypsum reinforced polypropylene inspection well special material. The addition of the surface activator modifies the phosphogypsum crystals, improves the compatibility of the phosphogypsum crystals and the polypropylene, enables the two to better combine during the mixing process, and improves the overall performance of the polypropylene inspection well special material.
[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of modified phosphogypsum reinforced polypropylene inspection well special material, comprising the following steps:
[0006] S1, filtering and drying the phosphogypsum crystals obtained after acid pickling of the phosphogypsum;
[0007] S2, adding a surface activator to the phosphogypsum crystals obtained in S1, and crystallizing after ball milling to obtain modified phosphogypsum crystals;
[0008] S3, mixing the dispersion liquid of the activator and the auxiliary activator with the polypropylene, adding the modified phosphogypsum crystals in S2 after mixing, uniformly mixing to obtain a mixture, and putting the mixture into a double-screw extruder, and cutting into particles after melt blending, water cooling and air cooling to obtain the polypropylene inspection well special material.
[0009] Preferably, in S1, one or more of dilute acetic acid and dilute hydrochloric acid is used for acid pickling.
[0010] Preferably, in S1, the temperature of dry crystallization is 80-100℃, and the time of dry crystallization is 6-8h.
[0011] Preferably, in S2, the adding amount of the surface activator is 0.1-2% of the mass of the phosphogypsum crystal, and the surface activator includes one or more of silane KH-550, silane KH-570, vinyl triethoxysilane, dodecyl phosphate and octadecyl phosphate.
[0012] Preferably, in S2, the crystallization temperature is 80-120℃, and the aspect ratio of the modified phosphogypsum crystal is 6-10.
[0013] Preferably, in S3, the mass ratio of the polypropylene and the modified phosphogypsum crystal is 60-80:40-20.
[0014] Preferably, in S3, the temperature of melt blending is 180-220℃.
[0015] Preferably, in S3, the adding amount of the activator is 0.05-0.2% of the mass of the polypropylene, and the activator includes one or more of dicumyl peroxide and tert-butyl peroxy-2-ethylhexyl carbonate.
[0016] Preferably, in S3, the adding amount of the auxiliary activator is 1-5% of the mass of the polypropylene, and the auxiliary activator includes one or more of cyanuric acid and triallyl isocyanurate.
[0017] Therefore, the application adopts the above-mentioned preparation method of the modified phosphogypsum reinforced polypropylene manhole special material, which has the following beneficial effects:
[0018] 1. The preparation method provided by the application removes impurities in the phosphogypsum through acid pickling, modifies the phosphogypsum crystal by adding a surface activator, improves the compatibility of the phosphogypsum crystal with the polypropylene, and makes the two better combined in the mixing process, thereby improving the overall performance of the polypropylene manhole special material.
[0019] 2. The application further promotes the mixing uniformity of the modified phosphogypsum crystal and the polypropylene by adding an ethanol dispersion of an activator and an auxiliary activator, and promotes the reaction between the components in the melt blending process of the twin-screw extruder, thereby improving the comprehensive performance of the polypropylene manhole special material.
[0020] 3. The application uses phosphogypsum as a raw material, which resources industrial solid waste, reduces the amount of polypropylene by adding the modified phosphogypsum crystal, and plays a reinforcing role in the polypropylene matrix, thereby improving the mechanical properties of the polypropylene manhole special material.
[0021] The technical solutions of the application will be further described in detail below through examples. DETAILED DESCRIPTION
[0022] The application will be further described below in connection with examples. Unless otherwise defined, technical or scientific terms used in the present application shall have the meanings commonly understood by one of ordinary skill in the art to which the present application pertains. The features or characteristics mentioned in the present application or the features mentioned in the specific examples can be combined in any manner, and the specific examples are only used to illustrate the present application and not to limit the scope of the present application.
[0023] The application provides a preparation method of modified phosphogypsum reinforced polypropylene manhole special material, comprising the following steps:
[0024] S1, filtering and drying the phosphogypsum crystal obtained after acid washing the phosphogypsum;
[0025] S2, adding a surface activator to the phosphogypsum crystal obtained in S1, and crystallizing after ball milling to obtain modified phosphogypsum crystal;
[0026] S3, mixing the dispersion liquid of the activator and the auxiliary activator with polypropylene, adding the modified phosphogypsum crystal in S2 after mixing, and uniformly mixing to obtain a mixture, and placing the mixture into a double screw extruder, and cutting into particles after melt blending, water cooling and air cooling to obtain the polypropylene manhole special material.
[0027] In some embodiments of the application, in S1, one or more of dilute acetic acid and dilute hydrochloric acid is used for acid washing. The acid can chemically react with impurities in the phosphogypsum, remove metal oxides and soluble organic matter in the phosphogypsum, thereby effectively improving the purity of the phosphogypsum and reducing the adverse effects of impurities on the performance of the subsequent material.
[0028] In some embodiments of the application, in S1, the temperature for drying and crystallizing is 80-100℃, and the time for drying and crystallizing is 6-8h. The moisture in the phosphogypsum can be fully removed, and the structure of the phosphogypsum crystal will not change due to the high temperature, thereby ensuring the chemical stability and facilitating the subsequent modification and mixing process.
[0029] In some embodiments of the application, in S2, the amount of the surface activator added is 0.1-2% of the mass of the phosphogypsum crystal, and the surface activator includes one or more of silane KH-550, silane KH-570, vinyl triethoxysilane, dodecyl phosphate and octadecyl phosphate. The molecular structure of the surface activator contains a group that can react with the hydroxyl group on the surface of the phosphogypsum, and the organic group at the other end has good affinity with polypropylene, thereby playing a bridging role between the phosphogypsum and polypropylene, enhancing the interfacial bonding force between the two, and improving the mechanical properties of the polypropylene manhole special material.
[0030] In some embodiments of the present application, in S2, the crystallization temperature is 80-120 DEG C, and the length-diameter ratio of the modified phosphogypsum crystal is 6-10. At the crystallization temperature, the surface activator can better act on the surface of the phosphogypsum crystal to form a uniform coating layer. The obtained modified phosphogypsum crystal plays a role similar to that of a reinforcing fiber in a polypropylene matrix, effectively improving the mechanical properties of the material such as tensile strength and bending strength.
[0031] In some embodiments of the present application, in S3, the mass ratio of the polypropylene and the modified phosphogypsum crystal is 60-80:40-20. In this ratio range, the continuous phase characteristics of the polypropylene as a matrix material can be ensured to play its own excellent processing performance and chemical corrosion resistance, the modified phosphogypsum crystal can fully play a reinforcing role, the mechanical properties of the polypropylene inspection well special material can be optimized, and a large proportion of phosphogypsum can be utilized to reduce the cost.
[0032] In some embodiments of the present application, in S3, the temperature of the melt blending is 180-220 DEG C. The temperature is in the range of the melt processing temperature of the polypropylene, at which the polypropylene can be fully melted and has good fluidity, which is beneficial to the uniform dispersion of the modified phosphogypsum crystal therein, and under the action of the activator and the auxiliary activator, the two can better interact with each other to form a stable polypropylene inspection well special material.
[0033] In some embodiments of the present application, in S3, the addition amount of the activator is 0.05-0.2% of the mass of the polypropylene, and the activator includes one or more of dicumyl peroxide, t-butyl peroxy-2-ethylhexyl carbonate. The role of the activator is to initiate the crosslinking reaction of the polypropylene molecular chain or the chemical reaction with the surface of the modified phosphogypsum crystal during the melt blending process, to produce free radical structures in the polypropylene molecular chain and the organic structure molecular chain on the surface of the modified phosphogypsum. By using the activity of the newly generated free radicals, a covalent structure is formed at the interface, the bonding force between the polypropylene phase and the modified phosphogypsum phase is improved, the interaction within the polypropylene inspection well special material is enhanced, and the strength, heat resistance and other properties of the polypropylene inspection well special material are improved.
[0034] In some embodiments of the present application, in S3, the addition amount of the auxiliary activator is 1-5% of the mass of the polypropylene, and the auxiliary activator includes one or more of cyanuric acid and triallyl isocyanurate. The auxiliary activator is added to ethanol to form an ethanol dispersion of the auxiliary activator, the ethanol dispersion of the auxiliary activator is added to the polypropylene, and mixing is carried out in a high-speed mixer at about 80 DEG C with a speed of 1500-3000 r / min. During the mixing process, ethanol is volatilized, and the mixing is stopped after the ethanol is volatilized.
[0035] The auxiliary activator cooperates with the activator to promote the chemical reaction, and meanwhile, the auxiliary activator can improve the processing performance of the polypropylene inspection well special material, reduce the melt viscosity of the polypropylene inspection well special material, make the polypropylene inspection well special material more smooth in the extrusion process, improve the production efficiency, and further enhance the mechanical properties and heat resistance of the polypropylene inspection well special material.
[0036] Example 1
[0037] S1, phosphogypsum is acid washed with 20% dilute acetic acid and then filtered, and is dried and crystallized at 80 DEG C for 6h to obtain phosphogypsum crystals.
[0038] S2, a surface activator vinyl triethoxysilane is added to the phosphogypsum crystals obtained in S1, the addition amount of the surface activator is 0.8% of the mass of the phosphogypsum crystals, and after ball milling, the modified phosphogypsum crystals are obtained by crystallizing at 80 DEG C for 6h, the modified phosphogypsum crystals are white fibrous crystals, and the aspect ratio of the modified phosphogypsum crystals is 10.
[0039] S3, at 80 DEG C, an activator t-butyl peroxy-2-ethylhexyl carbonate with a mass of 0.1% of the polypropylene and an auxiliary activator triallyl isocyanurate with a mass of 5% of the polypropylene are mixed with the polypropylene. After mixing, the modified phosphogypsum crystals in S2 are added, and the mass ratio of the polypropylene K8303 to the modified phosphogypsum crystals is 70:30. After uniform mixing, a mixture is obtained, and the mixture is put into a double-screw extruder with a strong shearing thread combination, and when melt blending, the feeding section is at 180 DEG C, the melting section is at 210 DEG C, the mixing section is at 220 DEG C, and the die head is at 200 DEG C; after water cooling and air cooling, the mixture is cut into particles to obtain a polypropylene inspection well special material with a diameter of 2mm and a length of 2-3mm.
[0040] Example 2
[0041] S1, phosphogypsum is acid washed with 20% dilute hydrochloric acid and then filtered, and is dried and crystallized at 90 DEG C for 6h to obtain phosphogypsum crystals.
[0042] S2, a surface activator silane KH-550 is added to the phosphogypsum crystals obtained in S1, the addition amount of the surface activator is 0.8% of the mass of the phosphogypsum crystals. After ball milling, the modified phosphogypsum crystals are obtained by crystallizing at 90 DEG C for 6h, the modified phosphogypsum crystals are white fibrous crystals, and the aspect ratio of the modified phosphogypsum crystals is 8.
[0043] S3, 0.05% of the activator dicumyl peroxide by weight of the polypropylene and 5% of the auxiliary activator cyanuric acid ethanol dispersion by weight of the polypropylene were mixed with the polypropylene at 80°C, then the modified phosphogypsum crystals in S2 were added after mixing, the mass ratio of the polypropylene K8303 and the modified phosphogypsum crystals was 70:30. After mixing evenly, the mixture was put into a double screw extruder with strong shearing thread combination, when melt blending, the feeding section was 180°C, the melting section was 210°C, the mixing section was 220°C, and the die head was 200°C; after water cooling and air cooling, the particles with a diameter of 2mm and a length of 2-3mm were cut to prepare the granular product, and the polypropylene inspection well special material was obtained.
[0044] Example 3
[0045] S1, the phosphogypsum was pickled with 20% dilute acetic acid and then filtered, and the phosphogypsum crystals were obtained by drying and crystallizing at 80°C for 8h.
[0046] S2, the surface activator dodecyl phosphoric acid was added to the phosphogypsum crystals obtained in S1, the addition amount of the surface activator was 1% of the mass of the phosphogypsum crystals, after ball milling, the white crystalline modified phosphogypsum crystals were obtained by crystallizing at 80°C for 6h, and the aspect ratio of the modified phosphogypsum crystals was more than 8.
[0047] S3, 0.05% of the activator dicumyl peroxide by weight of the polypropylene and 5% of the auxiliary activator cyanuric acid ethanol dispersion by weight of the polypropylene were mixed with the polypropylene at 80°C, then the modified phosphogypsum crystals in S2 were added after mixing, the mass ratio of the polypropylene K8303 and the modified phosphogypsum crystals was 70:30. After mixing evenly, the mixture was put into a double screw extruder with strong shearing thread combination, when melt blending, the feeding section was 180°C, the melting section was 210°C, the mixing section was 220°C, and the die head was 200°C; after water cooling and air cooling, the particles with a diameter of 2mm and a length of 2-3mm were cut to prepare the granular product, and the polypropylene inspection well special material was obtained.
[0048] Example 4
[0049] S1, the phosphogypsum was pickled with 20% dilute hydrochloric acid and then filtered, and the phosphogypsum crystals were obtained by drying and crystallizing at 80°C for 6h.
[0050] S2, the surface activator vinyl triethoxy silane was added to the phosphogypsum crystals obtained in S1, the addition amount of the surface activator was 0.8% of the mass of the phosphogypsum crystals, after ball milling, the white crystalline modified phosphogypsum crystals were obtained by crystallizing at 80°C for 6h, and the aspect ratio of the modified phosphogypsum crystals was 10.
[0051] S3, at 80℃, the polypropylene was mixed with the activator dicumyl peroxide with a mass fraction of 0.05% in polypropylene and the auxiliary activator triallyl isocyanurate with a mass fraction of 5% in polypropylene, then the modified phosphogypsum crystal in S2 was added, the mass ratio of polypropylene (80% K8303 and 20% K4912) and the modified phosphogypsum crystal was 65:35. After mixing evenly, the mixture was put into a twin-screw extruder with strong shearing thread combination, the feeding section was at 180℃, the melting section was at 210℃, the mixing section was at 220℃, and the die head was at 200℃; after water cooling and air cooling, the mixture was cut into particles with a diameter of 2mm and a length of 2-3mm, and the polypropylene inspection well special material was obtained.
[0052] Example 5
[0053] S1, the phosphogypsum was acid washed with 20% dilute hydrochloric acid and then filtered, and the phosphogypsum crystal was obtained by drying and crystallizing at 100℃ for 6h.
[0054] S2, the surface activator vinyltriethoxysilane was added to the phosphogypsum crystal obtained in S1, the addition amount of the surface activator was 0.8% of the mass of the phosphogypsum crystal, and the fibrous white crystalline modified phosphogypsum crystal was obtained by ball milling and crystallizing at 100℃, the aspect ratio of the modified phosphogypsum crystal was 7.
[0055] S3, at 80℃, the polypropylene was mixed with the activator dicumyl peroxide with a mass fraction of 0.05% in polypropylene and the auxiliary activator triallyl isocyanurate with a mass fraction of 5% in polypropylene, then the modified phosphogypsum crystal in S2 was added, the mass ratio of polypropylene (80% K8303 and 20% K4912) and the modified phosphogypsum crystal was 65:35. After mixing evenly, the mixture was put into a twin-screw extruder with strong shearing thread combination, the feeding section was at 180℃, the melting section was at 210℃, the mixing section was at 220℃, and the die head was at 200℃; after water cooling and air cooling, the mixture was cut into particles with a diameter of 2mm and a length of 2-3mm, and the polypropylene inspection well special material was obtained.
[0056] Test Example 1
[0057] a, contact angle test of the modified phosphogypsum crystal
[0058] The modified phosphogypsum crystal obtained in Examples 1-5 was subjected to a contact angle test, and the results are shown in Table 1.
[0059] Table 1, contact angle data table of the modified phosphogypsum crystal obtained in Examples 1-5
[0060]
[0061] The contact angle is an important index for measuring the wettability of a solid surface, and the greater the contact angle, the stronger the hydrophobicity of the solid surface. As can be seen from Table 1, the modified phosphogypsum crystals obtained have hydrophobicity, and in the preparation of the modified phosphogypsum crystals, the surface activator is successfully coated on the surface of the phosphogypsum crystals, changes the surface properties thereof, changes the hydrophilicity thereof into strong hydrophobicity, and a large number of hydrophobic groups are directed outward, so that the contact angle is significantly increased.
[0062] The modified phosphogypsum crystals with hydrophobicity are used for compounding with polypropylene, which can reduce the invasion of water into the polypropylene inspection well special material and improve the water resistance thereof. On the other hand, good hydrophobicity is also conducive to better dispersion of the polypropylene inspection well special material in the polypropylene matrix and avoids agglomeration. Since the polypropylene itself is also a hydrophobic material, the compatibility of the two is improved due to the similar hydrophobicity, thereby positively affecting the mechanical properties of the polypropylene inspection well special material.
[0063] b. Mechanical property test of the polypropylene inspection well special material
[0064] The mechanical properties of the polypropylene inspection well special material prepared in Examples 1-5 are tested, and the results are shown in Table 2.
[0065] Table 2, mechanical property data table of the polypropylene inspection well special material prepared in Examples 1-5
[0066]
[0067] The mechanical properties of the polypropylene used in Examples 1-5 are tested, and the results are shown in Table 3.
[0068] Table 3, mechanical property data table of the polypropylene used in Examples 1-5
[0069]
[0070] As can be seen from Table 2 and Table 3, in the preparation method provided by the present application, the modified phosphogypsum crystals used play a reinforcing role in the polypropylene matrix, improve the tensile strength, but the impact strength decreases to different degrees.
[0071] Therefore, in the preparation method of the polypropylene inspection well special material reinforced by the modified phosphogypsum, the surface activator is added to modify the phosphogypsum crystals, improve the compatibility of the phosphogypsum crystals with the polypropylene, so that the two can be better combined during mixing, and the overall performance of the polypropylene inspection well special material is improved.
[0072] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.
Claims
1. A method for preparing modified phosphogypsum-reinforced polypropylene inspection well material, characterized in that: Includes the following steps: S1. After acid washing and filtration, phosphogypsum is dried and crystallized to obtain phosphogypsum crystals. S2. Add a surfactant to the phosphogypsum crystals obtained in S1, ball mill and crystallize to obtain modified phosphogypsum crystals; S3. Mix the dispersion of activator and auxiliary activator with polypropylene, then add the modified phosphogypsum crystals from S2. After mixing evenly, a mixture is obtained. The mixture is then placed in a twin-screw extruder, melt-blended, water-cooled, air-cooled, and pelletized to obtain polypropylene inspection well material. In S2, the amount of surfactant added is 0.1-2% of the mass of phosphogypsum crystals. The surfactant includes one or more of silane KH-550, silane KH-570, vinyltriethoxysilane, dodecyl phosphate, and octadecyl phosphate. In S2, the crystallization temperature is 80-120℃, and the aspect ratio of the modified phosphogypsum crystals is 6-10. In S3, the mass ratio of polypropylene to modified phosphogypsum crystals is 60-80:40-20; In S3, the amount of activator added is 0.05-0.2% of the mass of polypropylene. The activator includes one or more of dicumyl peroxide and tert-butyl percarbonate-2-ethylhexyl ester. In S3, the amount of auxiliary activator added is 1-5% of the mass of polypropylene. The auxiliary activator includes one or more of cyanuric acid and triallyl isocyanurate.
2. The preparation method of the modified phosphogypsum-reinforced polypropylene inspection well material according to claim 1, characterized in that: In S1, pickling is performed using one or more of dilute acetic acid and dilute hydrochloric acid.
3. The preparation method of the modified phosphogypsum-reinforced polypropylene inspection well material according to claim 1, characterized in that: In S1, the drying and crystallization temperature is 80-100℃, and the drying and crystallization time is 6-8h.
4. The preparation method of the modified phosphogypsum-reinforced polypropylene inspection well material according to claim 1, characterized in that: In S3, the melt blending temperature is 180-220℃.