Polyethylene-silicon dioxide nanoparticle composite material and its preparation method and application

Abstract

The present invention discloses a polyethylene-silica nanoparticle composite material, its preparation method, and its application, relating to the technical field of anti-pollution materials. The composite material comprises a polyethylene matrix and silica nanoparticles dispersed within the polyethylene matrix. By adding silica nanoparticles to the polyethylene matrix, the pore structure of the polyethylene material is modified, thereby improving the relative hydrophilicity, mechanical properties, and water permeability of the polyethylene material. This enhanced hydrophilicity of the polyethylene material prevents the attachment of organisms to the polyethylene surface, thereby enhancing its anti-pollution capabilities.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-pollution materials, and in particular to a polyethylene-silicon dioxide nanoparticle composite material and a preparation method and application thereof. Background Art

[0002] Floating photovoltaic power stations are a new type of photovoltaic power station that uses floating structures to support photovoltaic modules. They can be widely used in areas with surface water, such as coal mining subsidence areas, lakes, and reservoirs. Floating photovoltaic power stations do not occupy arable land and are suitable for areas with abundant water resources but limited land resources. The use of floating photovoltaic power stations can reduce water evaporation, inhibit algae growth, and protect water resources.

[0003] Floating photovoltaic power plants often use polyethylene (HDPE) as the support material for their buoys. HDPE boasts numerous excellent properties, including good mechanical strength, chemical resistance, and thermal stability. However, due to its inherent hydrophobicity, non-wetting properties, lack of reactive functional groups, and high affinity for dirt, organisms easily attach to its surface, increasing the weight of the buoys and gradually corroding them, leading to failure of the support material and impacting the power generation efficiency and cost of the floating photovoltaic power plant.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a polyethylene-silicon dioxide nanoparticle composite material and a preparation method and application thereof.

[0006] The present invention is achieved in that:

[0007] In a first aspect, the present invention provides a polyethylene-silica nanoparticle composite material comprising a polyethylene matrix and silica nanoparticles dispersed in the polyethylene matrix.

[0008] In an alternative embodiment, the polyethylene is high density polyethylene.

[0009] Preferably, the molecular weight of the high-density polyethylene is 3-6 million.

[0010] In an alternative embodiment, the weight ratio of the silica nanoparticles to the high-density polyethylene is 0.25 to 0.5%.

[0011] Preferably, the particle size of the silicon dioxide nanoparticles is 100-150 nm.

[0012] In an alternative embodiment, the polyethylene-silica nanoparticle composite material is in the shape of a film, a plate, or a pipe.

[0013] In a second aspect, the present invention provides a method for preparing a polyethylene-silica nanoparticle composite material as described in any of the aforementioned embodiments, comprising dispersing silica nanoparticles and a polyethylene raw material in a diluent and heating and melting them to obtain a polyethylene-silica nanoparticle mixed liquid, and solidifying the polyethylene-silica nanoparticle mixed liquid to obtain a polyethylene-silica nanoparticle composite material.

[0014] In an optional embodiment, the heating and melting includes heating and melting the polyethylene raw material and the silica nanoparticles in the sealed container in an oil bath.

[0015] Preferably, the heating and melting temperature is 150-170° C., the melting time is 80-100 min, stirring is maintained during the melting process, and the stirring speed is 400-500 rpm.

[0016] Preferably, the oil bath includes any one of a methyl silicone oil bath, an ethyl silicone oil bath, and a trifluoropropyl silicone oil bath.

[0017] In an optional embodiment, dispersing the silicon dioxide nanoparticles and the polyethylene raw material in the diluent includes: first dispersing the silicon dioxide nanoparticles in the diluent, and then adding the polyethylene raw material to the diluent.

[0018] Preferably, the mass volume ratio of the silica nanoparticles to the diluent is 1 g:10-20 mL.

[0019] Preferably, the diluent includes any one of mineral oil and liquid paraffin.

[0020] Preferably, dispersing the silicon dioxide nanoparticles in the diluent comprises using ultrasonic dispersion, and the ultrasonic time is 20 to 40 minutes.

[0021] In an optional embodiment, solidification includes casting the polyethylene-silicon dioxide nanoparticle mixture into a mold and then placing the mixture in a room temperature water bath for solidification.

[0022] Preferably, the temperature of the normal temperature water bath is 24-30°C.

[0023] In an optional embodiment, after solidification and molding, the polyethylene-silicon dioxide nanoparticle composite material is placed in a cleaning agent for cleaning.

[0024] Preferably, the cleaning agent includes any one of acetone, sodium hydroxide and acetone containing 1% Tween.

[0025] In a third aspect, the present invention provides a polyethylene-silica nanoparticle composite material according to any one of the aforementioned embodiments or a polyethylene-silica nanoparticle composite material prepared by the preparation method according to any one of the aforementioned embodiments in an anti-pollution material.

[0026] The present invention has the following beneficial effects:

[0027] The present invention provides a polyethylene-silicon dioxide nanoparticle composite material, its preparation method, and its application. By adding silicon dioxide nanoparticles to polyethylene, the pore structure of the polyethylene material is modified, thereby improving the relative hydrophilicity, mechanical properties, and water permeability of the polyethylene material. This enhanced hydrophilicity prevents the attachment of organisms to the polyethylene surface, thereby enhancing its anti-pollution capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a scanning electron microscope image of the polyethylene-silicon dioxide nanoparticle composite film layer provided in Example 1 of the present invention;

[0030] Figure 2 This is a scanning electron microscope image of the polyethylene-silicon dioxide nanoparticle composite film layer provided in Example 2 of the present invention;

[0031] Figure 3 This is a scanning electron microscope image of the polyethylene-silicon dioxide nanoparticle composite film layer provided in Comparative Example 1 of the present invention;

[0032] Figure 4 This is a scanning electron microscope image of the polyethylene-silicon dioxide nanoparticle composite film layer provided in Comparative Example 2 of the present invention;

[0033] Figure 5 This is a graph showing the pure water flux results of different polyethylene-silica nanoparticle composite membrane layers provided in Experimental Example 2 of the present invention. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0035] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0036] In a first aspect, the present invention provides a polyethylene-silica nanoparticle composite material comprising a polyethylene matrix and silica nanoparticles dispersed in the polyethylene matrix.

[0037] The present invention modifies the pore structure of polyethylene materials by adding silicon dioxide nanoparticles to polyethylene, thereby improving the relative hydrophilicity, mechanical properties, and water permeability of polyethylene materials. The increased hydrophilicity of the polyethylene material prevents the attachment of organisms to the polyethylene surface, thereby enhancing its anti-pollution ability.

[0038] Preferably, the silicon dioxide nanoparticles are uniformly dispersed in the polyethylene matrix to ensure that the overall anti-pollution ability and overall mechanical properties of the polyethylene-silicon dioxide nanoparticle composite material are improved.

[0039] In an alternative embodiment, the polyethylene is high-density polyethylene (HDPE). HDPE is rigid and tough, possesses high chemical resistance, and has excellent thermal stability. However, HDPE's non-wetting properties, weak biocompatibility, and inherent hydrophobicity make it susceptible to adsorption by hydrophobic particles and proteins, leading to surface contamination. Therefore, the inventors employed silica nanoparticles as a dispersed filler material to increase the HDPE's hydrophilicity and reduce its tendency to adsorb proteins and hydrophobic particles.

[0040] Preferably, the molecular weight of the high-density polyethylene is 3-6 million.

[0041] In an optional embodiment, the weight ratio of silica nanoparticles to high-density polyethylene is 0.25-0.5%; for example, the weight ratio of silica nanoparticles to high-density polyethylene can be 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%.

[0042] Preferably, the particle size of the silicon dioxide nanoparticles is 100-150 nm.

[0043] In an optional embodiment, the polyethylene-silicon dioxide nanoparticle composite material can be in the form of a film, a plate, or a pipe. The specific shape of the polyethylene-silicon dioxide nanoparticle composite material can be selected according to actual needs. For example, when the polyethylene-silicon dioxide nanoparticle composite material is to be prepared as a support material for a buoy in a water-surface photovoltaic power station, the polyethylene-silicon dioxide nanoparticle composite material can be in the form of a film layer so that it can be directly applied to the buoy surface.

[0044] In a second aspect, the present invention provides a method for preparing a polyethylene-silica nanoparticle composite material as described in any of the aforementioned embodiments, comprising dispersing silica nanoparticles and a polyethylene raw material in a diluent and heating and melting them to obtain a polyethylene-silica nanoparticle mixed liquid, and then solidifying the polyethylene-silica nanoparticle mixed liquid to obtain a polyethylene-silica nanoparticle composite material.

[0045] By using a diluent to disperse the polyethylene raw material and silica nanoparticles, the silica nanoparticles can be evenly dispersed in the polyethylene raw material, improving the overall performance of the polyethylene material. Heating and melting facilitates the reaction between the polyethylene raw material and the silica nanoparticles, resulting in a finer and more uniform pore structure in the resulting polyethylene-silica nanoparticle composite material, improving the relative hydrophilicity, mechanical properties, water permeability, and anti-fouling capabilities of the polyethylene material.

[0046] In an optional embodiment, the heating and melting includes heating and melting the polyethylene raw material and the silicon dioxide nanoparticles in the sealed container in an oil bath. The oil bath can heat the raw materials more evenly at a higher temperature, which is beneficial to the reaction process of the polyethylene raw material and the silicon dioxide nanoparticles.

[0047] Preferably, the heating and melting temperature is 150-170°C, for example, 150°C, 155°C, 160°C, 165°C or 170°C.

[0048] Preferably, the heating and melting time is 80 to 100 minutes, for example, 80 minutes, 85 minutes, 90 minutes, 95 minutes or 100 minutes.

[0049] Preferably, stirring is maintained during the heating and melting process, and the stirring speed is 400-500 rpm; for example, it can be 400 rpm, 420 rpm, 440 rpm, 460 rpm, 480 rpm or 500 rpm.

[0050] Preferably, the oil bath includes any one of a methyl silicone oil bath, an ethyl silicone oil bath, and a trifluoropropyl silicone oil bath.

[0051] In an optional embodiment, dispersing the silicon dioxide nanoparticles and the polyethylene raw material in the diluent includes: first dispersing the silicon dioxide nanoparticles in the diluent, and then adding the polyethylene raw material to the diluent.

[0052] Preferably, the mass volume ratio of the silica nanoparticles to the diluent is 1 g:10-20 mL.

[0053] Preferably, the diluent includes any one of mineral oil and liquid paraffin, preferably mineral oil.

[0054] Preferably, dispersing the silicon dioxide nanoparticles in the diluent comprises using ultrasonic dispersion, and the ultrasonic time is 20 to 40 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes.

[0055] In an optional embodiment, solidification includes casting the polyethylene-silicon dioxide nanoparticle mixture into a mold and then placing the mixture in a room temperature water bath for solidification.

[0056] Preferably, the temperature of the normal temperature water bath is 24-30°C, for example, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C.

[0057] In an optional embodiment, after solidification, the polyethylene-silicon dioxide nanoparticle composite material is placed in a cleaning agent for cleaning to remove the diluent. The cleaning agent is mainly a material that is volatile at room temperature to facilitate removal of the cleaning agent.

[0058] Preferably, the cleaning agent comprises any one of acetone, sodium hydroxide or acetone containing 1% Tween.

[0059] In a third aspect, the present invention provides a polyethylene-silica nanoparticle composite material according to any one of the aforementioned embodiments or a polyethylene-silica nanoparticle composite material prepared by the preparation method according to any one of the aforementioned embodiments in an anti-pollution material.

[0060] Example 1

[0061] This embodiment provides a polyethylene-silicon dioxide nanoparticle composite material, the preparation method of which is as follows:

[0062] S01. Weigh 2 g of silica nanoparticles with a particle size of 100 nm, place them in 30 ml of mineral oil, and perform ultrasonic treatment for 30 minutes to uniformly disperse the silica nanoparticles in the mineral oil to prepare a silica dispersion.

[0063] S02. Weigh 10 g of high-density polyethylene and add it to the silica dispersion prepared in step S01. Seal the reaction vessel and place it in a silicone oil bath for heating and melting to obtain a polyethylene-silica nanoparticle mixture.

[0064] The molecular weight of the high-density polyethylene is 4 million, the heating and melting temperature is 160° C., the time is 90 minutes, and stirring is maintained during the melting process at a stirring speed of 450 rpm.

[0065] S03. Casting a polyethylene-silica nanoparticle mixture onto the surface of a preheated glass substrate to form a polyethylene-silica nanoparticle composite film layer with a thickness of 400 μm. After the film layer is in a semi-formed state, it is placed in a 27°C pure water coagulation bath for phase separation to produce a polyethylene-silica nanoparticle composite film layer. The film layer is then washed in acetone to remove the diluent. After washing, the film layer is dried at room temperature to remove the acetone from the surface.

[0066] Example 2

[0067] This embodiment provides a polyethylene-silicon dioxide nanoparticle composite material, the preparation method of which is as follows:

[0068] S01. Weigh 2 g of silica nanoparticles with a particle size of 120 nm and place them in 30 ml of mineral oil. Ultrasonicate for 30 minutes to uniformly disperse the silica nanoparticles in the mineral oil to prepare a silica dispersion.

[0069] S02. Weigh 20 g of high-density polyethylene and add it to the silica dispersion prepared in step S01. Seal the reaction vessel and place it in a silicone oil bath for heating and melting to obtain a polyethylene-silica nanoparticle mixture.

[0070] The molecular weight of the high-density polyethylene is 5 million, the heating and melting temperature is 160° C., the time is 90 minutes, and stirring is maintained during the melting process at a stirring speed of 450 rpm.

[0071] S03. Casting a polyethylene-silica nanoparticle mixture onto the surface of a preheated glass substrate to form a polyethylene-silica nanoparticle composite film layer with a thickness of 400 μm. After the film layer is in a semi-formed state, it is placed in a 27°C pure water coagulation bath for phase separation to produce a polyethylene-silica nanoparticle composite film layer. The film layer is then washed in acetone to remove the diluent. After washing, the film layer is dried at room temperature to remove the acetone from the surface.

[0072] Comparative Example 1

[0073] This comparative example provides a polyethylene-silicon dioxide nanoparticle composite material, the preparation method of which is similar to that of Example 1, except that the mass ratio of silicon dioxide nanoparticles to high-density polyethylene is 1%.

[0074] Comparative Example 2

[0075] This comparative example provides a polyethylene-silicon dioxide nanoparticle composite material, and its preparation method is similar to that of Example 1, except that no silicon dioxide nanoparticles are added.

[0076] Comparative Example 3

[0077] This comparative example provides a polyethylene-silicon dioxide nanoparticle composite material, the preparation method of which is similar to that of Example 1, except that the diameter of the selected silicon dioxide nanoparticles is greater than 150 nm.

[0078] Comparative Example 4

[0079] This comparative example provides a polyethylene-silica nanoparticle composite material, the preparation method of which is similar to that of Example 1, except that the heating and melting temperature is 140°C, the time is 90 minutes, and stirring is maintained during the melting process at a stirring speed of 450 rpm.

[0080] Test Example 1

[0081] The polyethylene-silicon dioxide nanoparticle composite film layers prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were observed under a scanning electron microscope. Figures 1 to 4 Results shown.

[0082] Depend on Figures 1 to 4 It can be seen that all membrane layers exhibit a leaf-like structure, but the membrane layers of Examples 1 and 2 of the present invention form finer and more uniform pores, which is beneficial for the use of microporous membranes for separation. When the silica content increases, the structure of Comparative Example 1 becomes denser and has lower porosity. When the silica content is 0, the structure of Comparative Example 2 has larger pores and poor pore uniformity.

[0083] Test Example 2

[0084] The polyethylene-silicon dioxide nanoparticle composite film layers prepared in Examples 1 to 2 and Comparative Examples 1 to 4 were subjected to hydrophilicity testing and mechanical property testing.

[0085] The contact angle is measured by dropping liquid on the surface of a substrate made of a polyethylene-silicon dioxide nanoparticle composite material and measuring it using a contact angle meter.

[0086] The detection method of relative pure water flux is: set the transmembrane pressure to 0.4 bar, the aeration parameter to 0.5 L / min, and use the ultrafiltration membrane flux measurement method for detection.

[0087] The average porosity is determined by weighing method.

[0088] The mechanical strength test method is the static test method.

[0089] The elongation at break was determined by tensile testing, and the results are shown in Table 1.

[0090] Table 1 Hydrophilicity and mechanical properties of polyethylene-silica nanoparticle composite film

[0091]

[0092] As shown in Table 1, the polyethylene-silica nanoparticle composite film provided by the embodiment of the present invention can take into account both the hydrophilicity and mechanical properties of the film layer, thereby obtaining a polyethylene-silica nanoparticle composite film layer with both hydrophilicity and good mechanical properties.

[0093] In addition, the pure water flux results of the polyethylene-silicon dioxide nanoparticle composite membrane layer of Example 1 and Comparative Example 2 are shown in FIG. Figure 5 Among them, the pure water flux of the membrane layer of Example 1 is always higher than that of the pure water flux of Comparative Example 2 due to its improved hydrophilicity.

[0094] Test Example 3

[0095] The anti-pollution ability of the polyethylene-silicon dioxide nanoparticle composite film layers prepared in Examples 1 to 2 and Comparative Examples 1 to 4 was tested.

[0096] The water flux J0 is calculated by the following formula (1):

[0097]

[0098] Where t is the time the water flows through, in h, V is the volume of the permeate at time t, in L, and A is the effective membrane surface area, in m 2 , the unit of water flux J0 is L / m 2 ·h.

[0099] The same conditions were used to perform continuous mode filtration on the sludge mixture in the polyethylene-silica nanoparticle composite membrane. After about 6 hours of filtration testing, the polyethylene-silica nanoparticle composite membrane was immersed in sewage, and the pure water flux value J1 after contamination was calculated according to formula (1). The filter cake layer on the membrane surface was then gently removed with a sponge, and the membrane was rinsed with deionized water. Finally, the polyethylene-silica nanoparticle composite membrane was fixed on the membrane assembly and used again for pure water filtration, and the treated pure water flux value J2 was calculated according to formula (1). The total fouling ratio (TFR), reversible fouling ratio (RFR), irreversible fouling ratio (IFR) and water flux recovery rate (FR) were calculated based on J1 and J2 to obtain the results shown in Table 2.

[0100] The calculation formulas for total fouling ratio (TFR), reversible fouling ratio (RFR), irreversible fouling ratio (IFR) and water flux recovery rate (FR) are as follows:

[0101]

[0102]

[0103]

[0104]

[0105] Table 2 Anti-pollution ability of polyethylene-silica nanoparticle composite film

[0106]

[0107]

[0108] As can be seen from Table 2, the total dirt in the embodiment of the present invention is significantly reduced compared with the control example, and the reversible dirt ratio and the irreversible dirt ratio are both low, and the water flux recovery rate is large. The silica content in Control Example 1 is increased. Although the irreversible dirt ratio is reduced, the reversible dirt ratio is relatively high, which increases the subsequent treatment process; in Control Example 2, no silica is added, and the reversible dirt ratio and the irreversible dirt ratio are both increased. After the irreversible dirt ratio increases, the subsequent treatment process is more difficult; in Control Example 3, the particle size of silica is larger, the reversible dirt is significantly increased, and the subsequent treatment process is increased; the melting temperature of Control Example 4 is low, resulting in the failure of the polyethylene-silica nanoparticle composite material to fully react, and the water flux recovery rate is low; This shows that the scheme of Example 1 of the present application has better anti-pollution effect and better water flux recovery rate.

[0109] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A polyethylene-silicon dioxide nanoparticle composite material, characterized in that: The invention comprises a polyethylene matrix and silicon dioxide nanoparticles dispersed in the polyethylene matrix, wherein the polyethylene is high-density polyethylene, the weight ratio of the silicon dioxide nanoparticles to the high-density polyethylene is 0.2-0.6%, and the particle size of the silicon dioxide nanoparticles is 100-150 nm; The preparation method of the polyethylene-silicon dioxide nanoparticle composite material comprises dispersing silicon dioxide nanoparticles and polyethylene raw materials in a diluent and heating and melting them to obtain a polyethylene-silicon dioxide nanoparticle mixed liquid, and solidifying the polyethylene-silicon dioxide nanoparticle mixed liquid to obtain the polyethylene-silicon dioxide nanoparticle composite material; The heating and melting temperature is 150-170° C., the melting time is 80-100 min, stirring is maintained during the melting process, and the stirring speed is 400-500 rpm.

2. The polyethylene-silicon dioxide nanoparticle composite material according to claim 1, characterized in that The molecular weight of the high-density polyethylene is 3 to 6 million.

3. The polyethylene-silicon dioxide nanoparticle composite material according to claim 1, characterized in that The polyethylene-silicon dioxide nanoparticle composite material may be in the shape of a film layer, a plate or a pipe.

4. The polyethylene-silicon dioxide nanoparticle composite material according to claim 1, characterized in that The heating and melting comprises performing oil bath heating and melting on the polyethylene raw material and the silicon dioxide nanoparticles in the sealed container.

5. The polyethylene-silicon dioxide nanoparticle composite material according to claim 4, characterized in that The oil bath includes any one of a methyl silicone oil bath, an ethyl silicone oil bath, and a trifluoropropyl silicone oil bath.

6. The polyethylene-silicon dioxide nanoparticle composite material according to claim 1, characterized in that The dispersing of the silicon dioxide nanoparticles and the polyethylene raw material in the diluent comprises: first dispersing the silicon dioxide nanoparticles in the diluent, and then adding the polyethylene raw material into the diluent.

7. The polyethylene-silicon dioxide nanoparticle composite material according to claim 6, characterized in that The mass volume ratio of the silicon dioxide nanoparticles to the diluent is 1 g:10-20 mL.

8. The polyethylene-silicon dioxide nanoparticle composite material according to claim 6, characterized in that The diluent includes any one of mineral oil and liquid paraffin.

9. The polyethylene-silicon dioxide nanoparticle composite material according to claim 6, characterized in that: Dispersing the silicon dioxide nanoparticles in the diluent includes using ultrasonic dispersion, and the ultrasonic time is 20 to 40 minutes.

10. The polyethylene-silicon dioxide nanoparticle composite material according to claim 1, characterized in that: The solidification comprises casting the polyethylene-silicon dioxide nanoparticle mixture into a mold and then placing the mixture in a water bath at room temperature for solidification.

11. The polyethylene-silicon dioxide nanoparticle composite material according to claim 10, characterized in that: The temperature of the normal temperature water bath is 24~30℃.

12. The polyethylene-silicon dioxide nanoparticle composite material according to claim 10, characterized in that: After solidification and molding, the method further comprises placing the polyethylene-silicon dioxide nanoparticle composite material in a cleaning agent for cleaning.

13. The polyethylene-silicon dioxide nanoparticle composite material according to claim 12, characterized in that: The cleaning agent includes either acetone or acetone containing 1% Tween.

14. Use of the polyethylene-silicon dioxide nanoparticle composite material according to any one of claims 1 to 13 in anti-pollution materials.

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