Piezoelectric-optical catalysis synergistic composite fiber for road and preparation method thereof

Abstract

The application provides a piezoelectric-photocatalytic synergic composite fiber for roads and a preparation method thereof, and belongs to the technical field of road engineering. 0.6 Mg 0.2 NbO3 and nitrogen-doped graphene to obtain a mixed solution, and obtains a core layer spinning solution after ultrasonic dispersion, adds Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material into an organic solvent to obtain a shell layer spinning solution; S2, the shell layer spinning solution and the core layer spinning solution are respectively placed into corresponding positions of a coaxial electrospinning device to perform coaxial electrospinning, and a composite fiber is collected; S3, the composite fiber is subjected to heat pressing treatment, and then is subjected to surface modification of a silane coupling agent to obtain the piezoelectric-photocatalytic synergic composite fiber. 0.6 Mg 0.2 NbO3, Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material. The application realizes the purposes of improving road mechanics and anti-skid performance and degrading automobile exhaust.

Description

Technical Field

[0001] This invention relates to the field of road engineering technology, specifically to a piezoelectric-photocatalytic synergistic composite fiber for road use and its preparation method. Background Technology

[0002] With the rapid development of the transportation industry, the road service environment is becoming increasingly complex, placing higher demands on the functional complexity of road engineering materials. Among these, fiber materials, as a key component for road structural reinforcement, have been widely used in asphalt mixtures, cement-stabilized base courses, and pavement functional layers, extending the service life of road structures through reinforcement and bridging effects. However, existing road fibers mostly focus on the single function of structural reinforcement, making it difficult to adapt to the complex needs of current road engineering. Especially on highways with high traffic volume and main urban roads with dense populations, pollutants such as nitrogen oxides, volatile organic compounds, and fine particulate matter emitted by vehicles not only exacerbate environmental problems such as photochemical smog and haze but also pose a significant threat to public health. Therefore, developing multifunctional fibers that combine improving the mechanical properties of road structures with the ability to degrade vehicle exhaust has become a key direction for achieving a synergy between safety and environmental protection requirements in road engineering.

[0003] In existing technologies, the real-time degradation of vehicle exhaust mainly involves directly incorporating photocatalytic particles (such as TiO2, ZnO, and g-C3N4) into asphalt, or preparing modified asphalt into a road surface coating. For example, Chinese patent document CN220202355U, entitled "A Low-Carbon and Environmentally Friendly Road," discloses a road comprising a primary environmentally friendly road body and a secondary environmentally friendly road body. Titanium dioxide particles within the primary environmentally friendly road body are mixed with asphalt concrete, allowing the titanium dioxide particles to be catalyzed by sunlight, catalyzing nitrogen oxides in the air and converting nitrogen oxides in vehicle exhaust into harmless nitrogen gas. However, commonly used photocatalytic materials in existing technologies suffer from narrow spectral response ranges and rapid photogenerated electron-hole recombination rates, resulting in low exhaust gas degradation efficiency.

[0004] To suppress photogenerated carrier recombination, existing technologies propose combining the piezoelectric effect with the photocatalytic effect to prepare piezoelectric-photocatalytic composite materials. These materials utilize the built-in electric field generated by the piezoelectric material under vehicle load to suppress carrier recombination. However, current piezoelectric-photocatalytic composite materials are mostly used in road surface coatings or fog seals. While they can achieve some exhaust gas degradation, they cover the original anti-skid texture of the road aggregate, leading to a decrease in road surface anti-skid performance and posing a potential risk to driving safety. Summary of the Invention

[0005] In view of this, the present invention provides a piezoelectric-photocatalytic synergistic composite fiber for road use and its preparation method, which achieves the purpose of improving road mechanics and anti-skid performance as well as degrading automobile exhaust.

[0006] To achieve the above objectives, the present invention provides a method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use, comprising the following steps:

[0007] S1. Dissolve PVDF in an organic solvent and add Li sequentially. 0.6 Mg 0.2 A mixture of NbO3 and nitrogen-doped graphene was obtained, and the mixture was ultrasonically dispersed to obtain a core-layer spinning solution; Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material was ultrasonically dispersed in an organic solvent to obtain a shell spinning solution;

[0008] S2. The core spinning solution is loaded into the inner shaft injector of the coaxial electrospinning device, and the shell spinning solution is loaded into the outer shaft injector of the coaxial electrospinning device to perform coaxial electrospinning and collect the composite fiber.

[0009] S3. The composite fiber is subjected to hot pressing treatment, and then surface modification with silane coupling agent is performed to obtain the piezoelectric-photocatalytic synergistic composite fiber.

[0010] In the technical solution provided by this invention, nitrogen-doped graphene is discontinuously attached to the interface between the core and shell layers. Its excellent conductivity forms a highly efficient conductive channel at the interface, improving the directional transport efficiency of charge carriers and enhancing catalytic efficiency. 0.5 Bi 0.5 FeO3 has an absorption spectrum covering 300-600nm, while Bi2O2Se can efficiently absorb visible light in the 500-800nm ​​range. The combination of the two can greatly improve the spectral response range of the photocatalytic material and form a heterojunction to effectively promote the separation of photogenerated electron-hole pairs and improve catalytic efficiency.

[0011] Optionally, the Li 0.6 Mg 0.2 NbO3 was prepared using the sol-gel method, comprising the following steps: CH3COOLi·2H2O, NbCl5, and MgCl2 were weighed according to stoichiometric ratios; CH3COOLi·2H2O was dissolved in deionized water to obtain solution A; NbCl5 was dissolved in H2O2 in a sealed beaker to obtain solution B; MgCl2 was dissolved in deionized water to obtain solution C; solutions A, B, and C were mixed, and citric acid was added while continuously stirring; the mixed solution was heated in an 80°C water bath and magnetically stirred until a sol was formed; the sol was dried to obtain a gel, which was then calcined to obtain Li. 0.6 Mg 0.2 NbO3 material.

[0012] Optionally, the water bath heating temperature is 75~85℃; the gel is calcined at 500~700℃ for 5~7h.

[0013] Optionally, the Pr 0.5 Bi 0.5 The preparation of FeO3 / Bi2O2Se composite material includes the following steps:

[0014] (1) Preparation of Pr by sol-gel method 0.5 Bi 0.5 FeO3: Pr(NO3)3·6H2O, Bi(NO3)3·5H2O, and Fe(NO3)3·9H2O were weighed out according to stoichiometric ratio and dissolved in ethylene glycol to obtain solutions D, E, and F; solutions D, E, and F were mixed, and citric acid was added under continuous stirring and magnetic stirring until a sol was formed; the sol was dried to obtain a gel, and the gel was calcined to obtain Pr 0.5 Bi 0.5 FeO3 nanomaterials;

[0015] (2) Preparation of Bi2O2Se by hydrothermal method: KOH is fully dissolved in deionized water; C6H is weighed according to stoichiometric ratio. 13 BiN2O7·H2O and Na2SeO3 were added to KOH solution and stirred to form a uniform milky white suspension. The suspension was transferred to a reaction vessel and placed in a forced-air drying oven for hydrothermal reaction. After the hydrothermal reaction was completed, the product was taken out and washed several times with deionized water and ethanol alternately to remove impurities. After drying, Bi2O2Se material was obtained.

[0016] (3) Preparation of Pr by hydrothermal method 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material: Weigh Pr according to the proportion 0.5 Bi 0.5 FeO3 and Bi2O2Se were dispersed in deionized water, and sonicated to ensure uniform solvent dispersion and mixing. The pH was adjusted, and the dispersion was transferred to a reaction vessel and placed in a drying oven for hydrothermal reaction. After the hydrothermal reaction, the product was removed and washed several times alternately with deionized water and ethanol to remove impurities, then dried. The dried product was then subjected to low-temperature annealing to enhance interfacial bonding, yielding Pr. 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material.

[0017] Optionally, in step (1), the gel is calcined at a temperature of 500~600℃ for 3~5h; in step (2), the hydrothermal reaction is carried out at 175~185℃ for 22~26h; in step (3), the pH is adjusted to 6~8, the hydrothermal reaction is carried out at 175~185℃ for 9~11h, the low-temperature annealing temperature is 200~300℃, and the annealing time is 1~2h.

[0018] Optionally, the Pr 0.5 Bi 0.5 Pr in FeO3 / Bi2O2Se composite material 0.5 Bi 0.5 The ratio of FeO3 to Bi2O2Se is (4~6):1.

[0019] Optionally, the PVDF accounts for 70-90% of the total mass of the core spinning solution; the Li 0.6 Mg 0.2 NbO3 accounts for 10-25% of the total mass of the core layer spinning solution; the nitrogen-doped graphene accounts for 0.5-5% of the total mass of the core layer spinning solution.

[0020] Optionally, the PVDF accounts for 75-85% of the total mass of the core spinning solution; the Li 0.6 Mg 0.2 NbO3 accounts for 15-20% of the total mass of the core layer spinning solution; the nitrogen-doped graphene accounts for 1-2.5% of the total mass of the core layer spinning solution.

[0021] Optionally, the solid mass concentration in the core spinning solution is 18%-25%; the solid mass concentration in the shell spinning solution is 4%-10%; and the propulsion speed ratio of the inner shaft injector to the outer shaft injector is 1:(1.5~2).

[0022] Optionally, the hot pressing treatment is a step-by-step hot pressing; the step-by-step hot pressing includes the following steps: first, holding at 70~90℃ and 4~6MPa for 25~35min to remove residual solvent, and then raising the temperature to 140~160℃ and 9~11MPa for 1~1.5h to promote PVDF crystallization.

[0023] Optionally, the silane coupling agent is one of hexadecyltrimethoxysilane, octyltriethoxysilane, and phenyltriethoxysilane.

[0024] To achieve the above objectives, the present invention also provides a piezoelectric-photocatalytic synergistic composite fiber for road use prepared by the above method, comprising a core layer and a shell layer enclosing the core layer.

[0025] Optionally, the core layer includes PVDF, Li 0.6 Mg 0.2 NbO3 and nitrogen-doped graphene, the shell being Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material; the surface of the piezoelectric-photocatalytic synergistic composite fiber is modified with a silane coupling agent to enhance its compatibility with asphalt.

[0026] To achieve the above objectives, the present invention also provides an application of piezoelectric-photocatalytic synergistic composite fiber for road use in an anti-skid thin layer of asphalt pavement. The method of use includes the following steps: cutting and uniformly dispersing the piezoelectric-photocatalytic synergistic composite fiber for road use in anti-skid aggregate; uniformly spreading tack coat emulsified asphalt on the road surface to provide an adhesion base for subsequent aggregates; uniformly spreading anti-skid aggregate before the tack coat emulsified asphalt breaks down and compacting it; and after cleaning up excess anti-skid aggregate, spreading seal coat emulsified asphalt.

[0027] In the technical solution provided by this invention, piezoelectric-photocatalytic synergistic composite fiber for road use is integrated as a functional component into the anti-skid thin layer of asphalt pavement. It is especially suitable for road sections such as highways and urban expressways that have stringent requirements for anti-skid safety, structural stability and environmental protection. The piezoelectric-photocatalytic synergistic composite fiber for road use can not only provide reinforcement, structural stability and interfacial adhesion for the anti-skid thin layer, but also achieve real-time and efficient degradation of vehicle exhaust through the enhanced piezoelectric-photocatalytic synergistic effect.

[0028] Optionally, the anti-skid aggregate is basalt; the length of the anti-skid aggregate is 4~8mm; the shear length of the piezoelectric-photocatalytic synergistic composite fiber for road use is 3~10mm; and the piezoelectric-photocatalytic synergistic composite fiber for road use accounts for 0.1~0.6% of the mass of the anti-skid aggregate.

[0029] Optionally, the shear length of the piezoelectric-photocatalytic synergistic composite fiber for road use is 5~8mm; the piezoelectric-photocatalytic synergistic composite fiber for road use accounts for 0.1~0.3% of the mass of the anti-skid aggregate.

[0030] The above-described technical solution of the present invention has at least the following beneficial effects:

[0031] The present invention has the following beneficial effects:

[0032] 1. The Pr in the piezoelectric-photocatalytic synergistic composite fiber for road use provided by this invention 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material exhibits a spectral response covering 300-800 nm, and can excite a large number of photogenerated electron-hole pairs under sunlight irradiation. Meanwhile, Pr 0.5 Bi 0.5 The heterojunction formed by FeO3 and Bi2O2Se can significantly suppress photogenerated carrier recombination and effectively prolong carrier lifetime. Its degradation efficiency of automobile exhaust is higher than that of single Pr. 0.5 Bi 0.5 FeO3 material improved by 13%.

[0033] 2. The nitrogen-doped graphene introduced into the piezoelectric-photocatalytic synergistic composite fiber for road use provided by the present invention can form a highly efficient conductive channel at the interface between the core layer and the shell layer, thereby improving the directional transport efficiency of charge carriers.

[0034] 3. The piezoelectric-photocatalytic synergistic composite fiber for road use provided by the present invention can provide reinforcement, structural stability and interfacial adhesion for the anti-skid thin layer. The flexural strength of the composite fiber-incorporated specimen is increased by 20% compared with the blank group, and the BPN value after wear is increased by 15.6% compared with the blank group. Through the enhanced piezoelectric-photocatalytic synergistic effect, the real-time and efficient degradation of automobile exhaust gas is achieved, and the degradation efficiency is increased by 72.8% compared with the PVDF core layer + TiO2 shell layer composite fiber. Attached Figure Description

[0035] Figure 1 Li in Embodiment 1 of the present invention 0.6 Mg 0.2 TEM image of NbO3 material;

[0036] Figure 2 In Embodiment 1 of the present invention, Pr 0.5 Bi 0.5 TEM image of FeO3 / Bi2O2Se composite material;

[0037] Figure 3 Li in Embodiment 1 of the present invention 0.6 Mg 0.2 Piezoelectric properties of NbO3 material;

[0038] Figure 4 In Embodiment 1 of the present invention, Pr 0.5 Bi 0.5 Absorption spectrum of FeO3 / Bi2O2Se composite material. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0040] The raw materials used in the embodiments of this invention are from the following sources:

[0041] PVDF: Shanghai Aladdin Biochemical Technology Co., Ltd., average M w ~534000;

[0042] Nitrogen-doped graphene: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥98%;

[0043] CH3COOLi·2H2O: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99%;

[0044] NbCl5: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99%;

[0045] MgCl2: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99%;

[0046] Pr(NO3)3·6H2O: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99.9%;

[0047] Bi(NO3)3·5H2O: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99%;

[0048] Fe(NO3)3·9H2O: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99.9%;

[0049] C6H 13 BiN2O7·H2O: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99%;

[0050] Na2SeO3: Sinopharm Chemical Reagent Co., Ltd., CP;

[0051] KOH: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥95%; TiO2: Sinopharm Chemical Reagent Co., Ltd., 99.9%;

[0052] Dimethylformamide: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99.5%;

[0053] Anhydrous ethanol: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99.5%;

[0054] Citric acid: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥99.5%;

[0055] Ethylene glycol: Shanghai Aladdin Biochemical Technology Co., Ltd., ≥98%;

[0056] H2O2: Shanghai Aladdin Biochemical Technology Co., Ltd., 30wt% aqueous solution;

[0057] Hexadecyltrimethoxysilane: Sinopharm Chemical Reagent Co., Ltd., 96%;

[0058] Octyltriethoxysilane: Sinopharm Chemical Reagent Co., Ltd., 97%;

[0059] Phenylacetoxysilane: Sinopharm Chemical Reagent Co., Ltd., 99%.

[0060] Example 1

[0061] This invention provides a method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use, comprising the following steps:

[0062] Li 0.6 Mg 0.2 NbO3 preparation: 3.3640 g of CH3COOLi·2H2O, 8.9151 g of NbCl5, and 3.1418 g of MgCl2 were weighed according to stoichiometric ratios. CH3COOLi·2H2O was dissolved in deionized water to obtain solution A. NbCl5 was dissolved in H2O2 in a sealed beaker to obtain solution B. MgCl2 was dissolved in deionized water to obtain solution C. Solutions A, B, and C were mixed, and 38.016 g of citric acid was added with continuous stirring. The mixture was heated in an 80°C water bath and magnetically stirred until a sol was formed. The sol was dried to obtain a gel, which was then calcined at 600°C for 6 hours to obtain Li. 0.6 Mg 0.2 NbO3 material.

[0063] Pr 0.5 Bi 0.5 The preparation of FeO3 / Bi2O2Se composite material includes the following steps:

[0064] (1) Weigh 18.7011g Pr(NO3)3·6H2O, 20.8541g Bi(NO3)3·5H2O and 17.3653g Fe(NO3)3·9H2O according to the stoichiometric ratio and dissolve them in ethylene glycol to obtain solutions D, E and F; mix solutions D, E and F, add 16.512g citric acid under continuous stirring, and stir magnetically until a sol is formed; dry the sol to obtain a gel, and calcine the gel at 550℃ for 4h to obtain Pr 0.5 Bi 0.5 FeO3 materials.

[0065] (2) Dissolve KOH completely in deionized water to prepare a KOH solution with a molar concentration of 3 mol / L; weigh 3.435 g of C6H according to the stoichiometric ratio. 13 BiN2O7·H2O and 1.3144g Na2SeO3 were added to KOH solution and magnetically stirred to form a uniform milky white suspension. The suspension was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set to 180℃ and the reaction time was 24h. After the reaction was completed, the product was taken out and washed several times with deionized water and ethanol alternately to remove impurities. After drying, Bi2O2Se material was obtained.

[0066] (3) Weigh 8g of Pr according to a 5:1 ratio. 0.5 Bi 0.5FeO3 and 1.6 g of Bi2O2Se were dispersed in deionized water, and the solvent was sonicated to ensure uniform dispersion and mixing. The pH was adjusted to 6-8, and the dispersion was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set to 180℃, and the reaction time was 10 h. After the reaction, the product was removed and washed several times alternately with deionized water and ethanol to remove impurities, and then dried. The dried product was then subjected to low-temperature annealing at 200℃ for 2 h to enhance interfacial bonding, yielding Pr. 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material.

[0067] S1: Dissolve 16.5g of PVDF powder in 100ml of dimethylformamide, stir until completely dissolved, then add 3.3g of Li... 0.6 Mg 0.2 NbO3 and 0.2 g of nitrogen-doped graphene were ultrasonically dispersed to obtain a core-layer spinning solution. The PVDF matrix accounted for 82.5% of the total mass of the core layer, and Li... 0.6 Mg 0.2 NbO3 accounts for 16.5% of the total mass of the core layer, nitrogen-doped graphene accounts for 1% of the total mass of the core layer, and the solid mass concentration in the core layer spinning solution is 20%. 6g of Pr 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material was ultrasonically dispersed in 100 ml of dimethylformamide to obtain a shell spinning solution. The solids concentration in the shell spinning solution was 6%.

[0068] S2: The core spinning solution is loaded into the inner shaft injector of the coaxial electrospinning apparatus, and the shell spinning solution is loaded into the outer shaft injector. Coaxial electrospinning is then performed with the inner shaft feed rate at 0.8 ml / h and the outer shaft feed rate at 1.44 ml / h. Composite fibers are then collected. The ratio of the inner shaft to the outer shaft feed rate is 1:1.8.

[0069] S3: The fiber surface solvent was removed by holding the hot-pressed fiber at 80℃ / 5MPa for 30 min, and then the fiber was held at 150℃ / 10MPa for 1 h to promote PVDF crystallization. The hot-pressed composite fiber was then immersed in an ethanol solution of hexadecyltrimethoxysilane for 1 h for surface modification, and then dried at 60℃ for 2 h to obtain piezoelectric-photocatalytic synergistic composite fiber for road use.

[0070] The piezoelectric-photocatalytic synergistic composite fiber for road use prepared above is applied to the anti-skid thin layer of asphalt pavement, and the specific application scheme is as follows:

[0071] The composite fibers were cut into 6mm short fibers and evenly dispersed in the anti-skid aggregate. A tack coat of emulsified asphalt was evenly sprayed onto the surface of the polished asphalt mixture rutting specimen to provide an adhesion base for subsequent aggregate application. Before the tack coat emulsified asphalt broke down, the anti-skid aggregate with the composite fibers was evenly spread and compacted. After removing excess aggregate, a top seal coat of emulsified asphalt was sprayed. The anti-skid aggregate was 5mm basalt; the piezoelectric-photocatalytic synergistic composite fiber for road use was added at 0.4% of the anti-skid aggregate.

[0072] Example 2

[0073] This invention provides a method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use, comprising the following steps:

[0074] Li 0.6 Mg 0.2 NbO3 preparation: 3.3640 g of CH3COOLi·2H2O, 8.9151 g of NbCl5, and 3.1418 g of MgCl2 were weighed according to stoichiometric ratios. CH3COOLi·2H2O was dissolved in deionized water to obtain solution A. NbCl5 was dissolved in H2O2 in a sealed beaker to obtain solution B. MgCl2 was dissolved in deionized water to obtain solution C. Solutions A, B, and C were mixed, and 38.016 g of citric acid was added with continuous stirring. The mixture was heated in a 75°C water bath and magnetically stirred until a sol was formed. The sol was dried to obtain a gel, which was then calcined at 500°C for 7 hours to obtain Li. 0.6 Mg 0.2 NbO3 material.

[0075] Pr 0.5 Bi 0.5 The preparation of FeO3 / Bi2O2Se composite material includes the following steps:

[0076] (1) Weigh 18.7011g Pr(NO3)3·6H2O, 20.8541g Bi(NO3)3·5H2O and 17.3653g Fe(NO3)3·9H2O according to the stoichiometric ratio and dissolve them in ethylene glycol to obtain solutions D, E and F; mix solutions D, E and F, add 16.512g citric acid under continuous stirring, and stir magnetically until a sol is formed; dry the sol to obtain a gel, and calcine the gel at 500℃ for 5h to obtain Pr 0.5 Bi 0.5 FeO3 materials.

[0077] (2) Dissolve KOH completely in deionized water to prepare a KOH solution with a molar concentration of 3 mol / L; weigh 3.435 g of C6H according to the stoichiometric ratio. 13BiN2O7·H2O and 1.3144g Na2SeO3 were added to KOH solution and magnetically stirred to form a uniform milky white suspension. The suspension was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set to 175℃ and the reaction time was 26h. After the reaction was completed, the product was taken out and washed several times with deionized water and ethanol alternately to remove impurities. After drying, Bi2O2Se material was obtained.

[0078] (3) Weigh 5g of Pr according to a 4:1 ratio. 0.5 Bi 0.5 FeO3 and 1.25 g of Bi2O2Se were dispersed in deionized water, and the solvent was sonicated to ensure uniform dispersion and mixing. The pH was adjusted to 6-8, and the dispersion was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set to 185℃, and the reaction time was 9 h. After the reaction, the product was removed and washed several times alternately with deionized water and ethanol to remove impurities, and then dried. The dried product was then subjected to low-temperature annealing at 250℃ for 1.5 h to enhance interfacial bonding, yielding Pr. 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material.

[0079] S1: Dissolve 16g of PVDF powder in 100ml of dimethylformamide, stir until completely dissolved, then add 3.5g of Li... 0.6 Mg 0.2 NbO3 and 0.5 g of nitrogen-doped graphene were ultrasonically dispersed to obtain a core-layer spinning solution. The PVDF matrix accounted for 80% of the total mass of the core layer, and Li... 0.6 Mg 0.2 NbO3 accounts for 17.5% of the total mass of the core layer, nitrogen-doped graphene accounts for 2.5% of the total mass of the core layer, and the solid mass concentration in the core layer spinning solution is 20%. 4g of Pr 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material was ultrasonically dispersed in 100 ml of dimethylformamide to obtain a shell spinning solution. The solids concentration in the shell spinning solution was 4%.

[0080] S2: The core spinning solution is loaded into the inner shaft injector of the coaxial electrospinning apparatus, and the shell spinning solution is loaded into the outer shaft injector. Coaxial electrospinning is performed with the inner shaft feed rate at 0.8 ml / h and the outer shaft feed rate at 1.2 ml / h. Composite fibers are then collected. The ratio of the inner shaft to the outer shaft feed rate is 1:1.5.

[0081] S3: The fiber surface solvent was removed by holding the hot-pressed fiber at 70℃ / 6MPa for 35 min, and then held at 140℃ / 11MPa for 1.5 h to promote PVDF crystallization. The composite fiber after hot pressing was immersed in an ethanol solution of octyltriethoxysilane for 1.5 h for surface modification, and then dried at 60℃ for 2 h to obtain piezoelectric-photocatalytic synergistic composite fiber for road use.

[0082] The application method is the same as in Example 1.

[0083] Example 3

[0084] This invention provides a method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use, comprising the following steps:

[0085] Li 0.6 Mg 0.2 Preparation of NbO3: 3.3640 g of CH3COOLi·2H2O, 8.9151 g of NbCl5, and 3.1418 g of MgCl2 were weighed according to stoichiometric ratios. CH3COOLi·2H2O was dissolved in deionized water to obtain solution A. NbCl5 was dissolved in H2O2 in a sealed beaker to obtain solution B. MgCl2 was dissolved in deionized water to obtain solution C. Solutions A, B, and C were mixed, and 38.016 g of citric acid was added with continuous stirring. The mixture was heated in an 85°C water bath and magnetically stirred until a sol was formed. The sol was dried to obtain a gel, which was then calcined at 700°C for 5 hours to obtain Li. 0.6 Mg 0.2 NbO3 material.

[0086] Pr 0.5 Bi 0.5 The preparation of FeO3 / Bi2O2Se composite material includes the following steps:

[0087] (1) Weigh 18.7011g Pr(NO3)3·6H2O, 20.8541g Bi(NO3)3·5H2O and 17.3653g Fe(NO3)3·9H2O according to the stoichiometric ratio and dissolve them in ethylene glycol to obtain solutions D, E and F; mix solutions D, E and F, add 16.512g citric acid while stirring continuously, and stir magnetically until a sol is formed; dry the sol to obtain a gel, and calcine the gel at 600℃ for 3h to obtain Pr 0.5 Bi 0.5 FeO3 materials.

[0088] (2) Dissolve KOH completely in deionized water to prepare a KOH solution with a molar concentration of 3 mol / L; weigh 3.435 g of C6H according to the stoichiometric ratio. 13BiN2O7·H2O and 1.3144g Na2SeO3 were added to KOH solution and magnetically stirred to form a uniform milky white suspension. The suspension was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set to 185℃ and the reaction time was 24h. After the reaction was completed, the product was taken out and washed several times with deionized water and ethanol alternately to remove impurities. After drying, Bi2O2Se material was obtained.

[0089] (3) Weigh 10g of Pr according to the ratio of 6:1 0.5 Bi 0.5 FeO3 and 2g Bi2O2Se were dispersed in deionized water, and the solvent was sonicated to ensure uniform dispersion and mixing. The pH was adjusted to 6-8, and the dispersion was transferred to a reaction vessel and placed in a forced-air drying oven. The reaction temperature was set at 175℃, and the reaction time was 11h. After the reaction, the product was removed and washed several times alternately with deionized water and ethanol to remove impurities, and then dried. The dried product was then subjected to low-temperature annealing at 300℃ for 1h to enhance interfacial bonding, yielding Pr. 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material.

[0090] S5: Dissolve 17.5g of PVDF powder in 100ml of dimethylformamide, stir until completely dissolved, then add 2g of Li... 0.6 Mg 0.2 NbO3 and 0.5 g of nitrogen-doped graphene were ultrasonically dispersed to obtain a core-layer spinning solution. The PVDF matrix accounted for 87.5% of the total mass of the core layer, and Li... 0.6 Mg 0.2 NbO3 accounts for 10% of the total mass of the core layer, nitrogen-doped graphene accounts for 2.5% of the total mass of the core layer, and the solid mass concentration in the core layer spinning solution is 20%. 10g of Pr 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material was ultrasonically dispersed in 100 ml of dimethylformamide to obtain a shell spinning solution. The solids concentration in the shell spinning solution was 10%.

[0091] S6: Load the core spinning solution into the inner shaft injector of the coaxial electrospinning apparatus, and load the shell spinning solution into the outer shaft injector. Perform coaxial electrospinning with the inner shaft feed rate at 0.8 ml / h and the outer shaft feed rate at 1.6 ml / h. Collect the composite fibers. The ratio of the inner shaft to the outer shaft feed rate is 1:2.

[0092] S7: The solvent on the fiber surface was removed by holding the hot-pressed fiber at 90℃ / 4MPa for 25 min, and then held at 160℃ / 9MPa for 1.5 h to promote PVDF crystallization. The composite fiber after hot pressing was immersed in an ethanol solution of phenyltriethoxysilane for 1 h for surface modification, and then dried at 60℃ for 2 h to obtain piezoelectric-photocatalytic synergistic composite fiber for road use.

[0093] The application method is the same as in Example 1.

[0094] Example 4

[0095] The only difference from Example 1 is that the piezoelectric-photocatalytic synergistic composite fiber for road use accounts for 0.3% of the mass of the anti-skid aggregate.

[0096] Comparative Example 1

[0097] Compared with Example 1, the only difference is that the piezoelectric-photocatalytic synergistic composite fiber for road use is not prepared; the application does not include the piezoelectric-photocatalytic synergistic composite fiber for road use, and the rest of the application steps are the same as those in Example 1.

[0098] Comparative Example 2

[0099] Compared with Example 1, the only difference is that the raw material for preparing the core layer is PVDF fiber, the raw material for the shell layer is TiO2 nanoparticles, the mass of the core layer is the same as that of the core layer in Example 1, and the mass of the shell layer is the same as that of the shell layer in Example 1; the remaining preparation steps and application methods are the same as those in Example 1.

[0100] Comparative Example 3

[0101] Compared with Example 1, the only difference is that the raw materials for the core layer are PVDF and Li. 0.6 Mg 0.2 NbO3, the shell material is TiO2, the mass of the core layer is the same as that of the core layer in Example 1, Li 0.6 Mg 0.2 The mass of NbO3 and the Li in Example 1 0.6 Mg 0.2 The total mass of NbO3 and nitrogen-doped graphene is the same, and the mass of the shell is the same as that of the shell in Example 1; the remaining preparation steps and application methods are the same as those in Example 1.

[0102] Comparative Example 4

[0103] Compared with Example 1, the only difference is that the raw material for the shell is TiO2, and the mass of the shell is the same as that of the shell in Example 1; the remaining preparation steps and application methods are the same as those in Example 1.

[0104] Comparative Example 5

[0105] Compared with Example 1, the only difference is that the raw material of the shell is Pr. 0.5 Bi 0.5 The FeO3 shell was prepared using the same method as that used in Example 1; the remaining steps and methods of preparation were identical to those used in Example 1.

[0106] Performance testing

[0107] For the Li prepared in Example 1 0.6 Mg 0.2 NbO3 materials, Pr 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material was subjected to transmission electron microscopy, and the results were obtained as follows: Figure 1 , Figure 2 . Figure 1 For Li 0.6 Mg 0.2 TEM image of NbO3 material. Figure 2 For Pr 0.5 Bi 0.5 TEM image of FeO3 / Bi2O2Se composite material.

[0108] Depend on Figure 2 It can be seen that the flake-shaped Bi₂O₂Se and the granular Pr 0.5 Bi 0.5 FeO3 composite, Bi2O2Se length: Pr 0.5 Bi 0.5 The FeO3 particle size ratio is 1:20.

[0109] To test the Li prepared in Example 1 0.6 Mg 0.2 The piezoelectric properties of NbO3 material were demonstrated by pressing five circular Li-containing sheets, each 15 mm in diameter and 1.2 mm thick. 0.6 Mg 0.2 NbO3 ceramics, designated S1 to S5, were sintered, silver-plated, and polarized before their piezoelectric constants (d) were measured. 33 ) and electromechanical coupling coefficient (k p Test results can be found in [link / reference]. Figure 3 .

[0110] Depend on Figure 3 It is known that Li with high piezoelectric activity has been synthesized. 0.6 Mg 0.2 NbO3 material, and the piezoelectric properties are well consistent.

[0111] Test Example 1 prepared Pr 0.5 Bi 0.5 The absorption spectrum of the FeO3 / Bi2O2Se composite material was obtained. Figure 4 .

[0112] Depend on Figure 4 It can be seen that for light in the 300-800nm ​​wavelength range, Pr 0.5 Bi 0.5 The FeO3 / Bi2O2Se composite material has a high absorption capacity.

[0113] Accelerated polishing was performed on paved anti-skid thin-layer rutting specimens using a road material friction performance testing system. The static pressure of the test wheel was 250 N, the loading linear speed was 30 km / h, the test temperature was 20-25℃, and the total wheel load duration was 12 hours. To ensure accelerated polishing, sand was added every 40 minutes. The exhaust gas degradation efficiency evaluation device was used to detect the vehicle exhaust gas degradation efficiency before and after simulated wear in Examples 1-4 and Comparative Examples 2-5. The rutting test machine was modified into a sealed, non-transparent reaction chamber. Vehicle exhaust gas generated by a gasoline engine was introduced into the reaction chamber through a vent. After the gas concentration stabilized, simulated vehicle load by wheel rolling and simulated illumination conditions by turning on a 20W full-spectrum lamp were provided. Another vent in the reaction chamber was connected to a nitrogen oxide analyzer. After stabilizing the reaction for 1 hour, NO was measured. X Degradation efficiency. The crack resistance of Examples 1-4 and Comparative Examples 1-5 before and after wear was investigated using a three-point bending test. The pendulum friction coefficients of Examples 1-4 and Comparative Examples 1-5 before and after wear were obtained using a pendulum friction meter. The test results are shown in Tables 1-3.

[0114] Table 1. Degradation efficiency of automobile exhaust before and after simulated wear in Examples 1-4 and Comparative Examples 2-5.

[0115]

[0116] Table 2. Bending tensile strength before and after wear in Examples 1-4 and Comparative Examples 1-5.

[0117]

[0118] Table 3. Pendulum friction coefficients (BPN) before and after wear in Examples 1-4 and Comparative Examples 1-5.

[0119]

[0120] Based on the test results in Tables 1, 2 and 3, it can be seen that the piezoelectric-photocatalytic synergistic composite fiber of the present invention, when applied to the anti-skid thin layer of asphalt pavement, can significantly improve the crack resistance and anti-skid performance of the anti-skid thin layer, while introducing a real-time and efficient vehicle exhaust degradation function to the asphalt pavement.

[0121] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a piezoelectric-photocatalytic synergic composite fiber for road use, characterized by, The method comprises the following steps: S1, dissolving PVDF in an organic solvent, adding Li 0.6 Mg 0.2 NbO3 and nitrogen-doped graphene to obtain a mixed solution, ultrasonic dispersion of the mixed solution to obtain a core layer spinning solution; Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material is ultrasonically dispersed in an organic solvent to obtain a shell layer spinning solution; S2, the core layer of the spinning solution is loaded into the inner shaft injector of the coaxial electrospinning device, the shell layer of the spinning solution is loaded into the outer shaft injector of the coaxial electrospinning device, coaxial electrospinning is carried out, and a composite fiber is collected; S3, the composite fiber is subjected to heat pressing treatment, and then is subjected to surface modification of a silane coupling agent to obtain the piezoelectric-photocatalytic synergistic composite fiber.

2. The method for preparing a piezoelectric-photocatalytic synergic composite fiber for road according to claim 1, characterized in that, The Li 0.6 Mg 0.2 NbO3 was prepared by sol-gel method, The method comprises the following steps: respectively weighing CH3COOLi·2H2O, NbCl5 and MgCl2 according to stoichiometric ratios; dissolving CH3COOLi·2H2O in deionized water to obtain solution A; dissolving NbCl5 in H2O2, and the dissolving process is in a sealed beaker to obtain solution B; dissolving MgCl2 in deionized water to obtain solution C; mixing solutions A, B and C, and adding citric acid under continuous stirring; heating the mixed solution in a water bath, and magnetically stirring until a sol is formed; drying the sol to obtain a gel, and calcining the gel to obtain Li 0.6 Mg 0.2 NbO3 material.

3. The method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use according to claim 1, characterized in that, The Pr 0.5 Bi 0.5 The preparation of the FeO3 / Bi2O2Se composite material comprises the following steps: (1), Pr 0.5 Bi 0.5 FeO3: Pr(NO3)3·6H2O, Bi(NO3)3·5H2O and Fe(NO3)3·9H2O were weighed according to the stoichiometric ratio, dissolved in ethylene glycol to obtain solutions D, E and F; solutions D, E and F were mixed, and citric acid was added under continuous stirring, and magnetic stirring was performed until a sol was formed; the sol was dried to obtain a gel, and the gel was calcined to obtain Pr 0.5 Bi 0.5 FeO3nanomaterials; (2) Bi2O2Se is prepared by hydrothermal method: KOH is fully dissolved in deionized water; C6H 13 BiN2O7·H2O and Na2SeO3 are added into KOH solution, and stirred to form a uniform milky white suspension; the suspension is transferred into a reaction container, and placed in a blast drying oven for hydrothermal reaction; after the hydrothermal reaction is completed, the product is taken out, washed with deionized water and ethanol alternately for several times to remove impurities, and dried to obtain Bi2O2Se material; (3) Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material: Pr 0.5 Bi 0.5 FeO3 and Bi2O2Se are dispersed in deionized water, and ultrasonic is used to make the solvent disperse and mix uniformly; the PH is adjusted, the dispersion liquid is transferred to a reaction container, and is placed in a blast drying oven for hydrothermal reaction; after the hydrothermal reaction is completed, the product is taken out and washed with deionized water and ethanol alternately for several times to remove impurities, and is dried; the dried product is subjected to low-temperature annealing to enhance the interface bonding, and a Pr 0.5 Bi 0.5 FeO3 / Bi2O2Se composite material is obtained.

4. The method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use according to claim 1, characterized in that, The Pr 0.5 Bi 0.5 Pr in the FeO3 / Bi2O2Se composite material 0.5 Bi 0.5 The mass ratio of FeO3 to Bi2O2Se is (4-6):

1.

5. The method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use according to claim 1, characterized in that, The PVDF accounts for 70-90% of the total mass of the core layer spinning solution; the Li 0.6 Mg 0.2 The NbO3 accounts for 10-25% of the total mass of the core layer spinning solution; the nitrogen-doped graphene accounts for 0.5-5% of the total mass of the core layer spinning solution.

6. The method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use according to claim 1, characterized in that, The solid mass concentration in the core layer of the spinning solution is 18%-25%; the solid mass concentration in the shell layer of the spinning solution is 4%-10%; and the pushing speed ratio of the inner shaft injector to the outer shaft injector is 1: (1.5-2).

7. The method for preparing piezoelectric-photocatalytic synergistic composite fibers for road use according to claim 1, characterized in that, The heat pressing treatment is step-by-step heat pressing, which comprises the following steps: first, heat preservation at 70-90 DEG C, 4-6 MPa for 25-35 min to remove residual solvent, and then heating to 140-160 DEG C, 9-11 MPa for 1-1.5 h to promote PVDF crystallization.

8. The piezoelectric-photocatalytic synergic composite fiber for road use according to any one of claims 1 to 7, wherein the piezoelectric-photocatalytic synergic composite fiber for road use is produced by the production method according to any one of claims 1 to 7. The piezoelectric-photocatalytic synergistic composite fiber comprises a core layer and a shell layer wrapping the core layer.

9. The application of piezoelectric-photocatalytic synergic composite fiber in asphalt pavement anti-skid thin layer according to claim 8, characterized in that, The use method comprises the following steps: the piezoelectric-photocatalytic synergistic composite fiber is cut and uniformly dispersed in anti-skid aggregate; tack coat emulsified asphalt is uniformly spread on the road surface to provide an adhesion base for subsequent aggregate; before the tack coat emulsified asphalt is demulsified, the anti-skid aggregate is uniformly spread, and is rolled and formed; after the excess anti-skid aggregate is cleaned, seal coat emulsified asphalt is spread.

10. The application of piezoelectric-photocatalytic synergistic composite fiber in asphalt pavement anti-skid thin layer according to claim 9, characterized in that, The anti-skid aggregate is basalt; the length of the anti-skid aggregate is 4-8 mm; the length of the piezoelectric-photocatalytic synergistic composite fiber after being cut is 3-10 mm; and the piezoelectric-photocatalytic synergistic composite fiber accounts for 0.1-0.6% of the mass of the anti-skid aggregate. The method comprises the following steps:

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