Method for preparing perfluorinated sulfonic acid resin dispersion liquid based on liquid phase laser ablation technology

Abstract

The invention belongs to the technical field of high polymer material processing, and particularly relates to a method for preparing perfluorinated sulfonic acid resin dispersion liquid based on a liquid phase laser ablation technology. According to the method, solid particles of the perfluorinated sulfonic acid resin are taken as raw materials, the solid particles are soaked in an organic alcohol-water mixed solution after being smashed, and then laser beams are regulated and controlled through a galvanometer control system, so that the laser beams conduct laser corrosion on the perfluorinated sulfonic acid resin soaked in a solvent; the transient high-temperature and high-pressure effect generated by laser in a liquid phase environment is utilized to promote the solid perfluorosulfonic acid resin to be dissolved and dispersed in a solvent to form dispersion liquid. And meanwhile, a water cooling device is adopted to carry out system heat management, and homogenization treatment is assisted, so that the uniformity of the perfluorinated sulfonic acid resin dispersion liquid prepared by the laser corrosion reaction is kept in the preparation process, and denaturation is avoided. The application performance of the finally prepared dispersion liquid is consistent with that of industrial mature products, and the dispersion liquid has excellent storage stability and can be applied to the fields of proton exchange membrane preparation, catalyst coating preparation and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer material processing technology, specifically relating to a method for preparing perfluorosulfonic acid resin dispersion based on liquid phase laser ablation technology. Background Technology

[0002] Perfluorosulfonic acid resin (PFSA), or Nafion-H, is a class of ionomers composed of a hydrophobic perfluorocarbon backbone and hydrophilic sulfonic acid groups (-SO3H) side chains. It is also currently known as the strongest solid superacid. Its internal hydrophilic ion clusters are dispersed within the resin matrix, and these clusters are interconnected through channels through which water molecules and ions can migrate. This unique structure endows PFSA with excellent heat resistance, outstanding chemical and electrochemical stability, high mechanical strength, and excellent high proton conductivity and selective ion transport properties.

[0003] Perfluorosulfonic acid resin dispersions are derivatives of perfluorosulfonic acid resins. These materials exist as submicron or nano-sized colloidal particles and can be stably dispersed in alcohol-water mixed solvents, belonging to a typical colloidal system. Perfluorosulfonic acid resin dispersions are commonly used as binders, suitable for the preparation of materials such as electrolyte membranes, proton exchange membranes, and catalyst coating membranes. Simultaneously, as ion conductors, they can effectively promote mass transfer processes and improve electrochemical reaction efficiency. Commercially available perfluorosulfonic acid resin dispersions are available in four concentrations: 5%, 10%, 15%, and 20%. The 5% concentration product, due to its excellent flowability and ease of preparation, is widely used in experimental research in universities and research institutions for electrode modification and catalyst slurry preparation. The 15% and 20% concentration products are more suitable for large-scale industrial production applications.

[0004] Currently, the mainstream preparation process for commercial perfluorosulfonic acid resin dispersions is the alcohol-water solvent high-temperature and high-pressure method. Perfluorosulfonic acid resins possess unique physicochemical properties and have extremely low solubility in water. Therefore, appropriate organic solvents must be added, along with a high-temperature and high-pressure environment, to form a stable dispersion system. This process typically uses a mixture of high-boiling-point alcohols and water as the solvent, reacting it in a reactor under high-temperature and high-pressure conditions (>200 °C) for several hours. Then, a complex process replaces the solvent with the target alcohol, ultimately yielding the perfluorosulfonic acid resin dispersion. However, this mainstream process has significant drawbacks: the high-temperature and high-pressure reaction conditions place stringent requirements on the material and safety performance of the reactor; prolonged high-temperature and high-pressure treatment can easily cause denaturation of the perfluorosulfonic acid resin, thus affecting product performance; the overall process is cumbersome, time-consuming, and has low production efficiency; simultaneously, the process energy consumption and production costs are both relatively high. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a method for preparing perfluorosulfonic acid resin dispersions based on laser liquid phase ablation technology. This method employs laser liquid phase ablation technology, using a galvanometer control system to regulate laser parameters during processing, and a water-cooling device to achieve thermal management of the system. Simultaneously, homogenization treatment is used to homogenize the perfluorosulfonic acid resin, thereby achieving efficient and rapid batch preparation of perfluorosulfonic acid resin dispersions under ambient temperature and pressure conditions. The resulting product not only has application performance comparable to mature products in the industry but also possesses excellent storage stability. Furthermore, this method can significantly reduce production energy consumption and costs, providing a better technical route for the preparation of perfluorosulfonic acid resin dispersions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention provides a method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology. Specifically, perfluorosulfonic acid resin solid particles are used as raw materials and dispersed in an organic alcohol-water mixed solvent. The laser path is precisely controlled by a galvanometer control system, and a water-cooling device is used for system thermal management to ensure the system temperature is stably maintained within the range of 20–25°C. Based on this, a stepwise laser ablation process is used to treat the perfluorosulfonic acid resin in the system: first, the resin particles are pretreated by irradiation using a non-focused low-to-medium energy medium-to-high frequency laser; then, the pretreated resin is homogenized, and the laser is switched to a medium-to-high energy medium-to-high frequency laser focusing ablation mode to deeply ablate the resin. Utilizing the high-temperature, high-pressure localized environment created when the laser acts on the liquid phase, the perfluorosulfonic acid resin solid particles are efficiently dissolved and dispersed in the mixed solvent, ultimately yielding a stable perfluorosulfonic acid resin dispersion.

[0007] Preferably, the method for preparing perfluorosulfonic acid resin dispersion based on liquid phase laser ablation technology includes the following steps: S1. Pulverize the perfluorosulfonic acid resin solid particles to millimeter-sized particles, and then disperse them in an organic alcohol-water mixed solvent; S2. Apply an external temperature field to the mixed system in S1 through a water cooling device to achieve thermal management, so that the temperature of the system is stabilized at 20-25℃ during the subsequent laser liquid phase ablation process. This temperature range is within the normal temperature and pressure conditions, that is, the macroscopic working environment of the entire reaction system is at normal temperature and pressure, and it does not need to be heated to above 200℃ and subjected to high pressure as in mainstream processes.

[0008] S3. Under the condition of laser scanning control implemented by the galvanometer control system, the resin in the mixed solvent is subjected to laser liquid phase ablation treatment: first, the resin in the mixed solvent is pretreated by low-to-medium energy medium-to-high frequency laser non-focused irradiation, and then the pretreated resin is homogenized (the homogenization treatment ensures the uniformity of resin dissolution, timely discharges the reaction heat to the outside of the resin system, and avoids local overheating caused by laser action, which would denature the resin), and then the medium-to-high energy medium-to-high frequency laser focusing mode is switched to ablate the pretreated resin; thereby, the perfluorosulfonic acid resin is dissolved under the action of high-energy focused laser ablation to form a perfluorosulfonic acid resin dispersion.

[0009] More preferably, the equivalent weight (EW) of the perfluorosulfonic acid resin solid particles is 800 to 1100.

[0010] More preferably, the organic alcohol used in the organic alcohol-water mixed solvent is n-propanol, isopropanol, or ethanol, and the volume content of the organic alcohol is 40-80%.

[0011] More preferably, the laser liquid phase ablation treatment in S3 is performed using a YAG high-energy laser (Spectra-Physics Laser), which is equipped with a 355 nm to 1064 nm nanosecond laser and a 355 nm to 1064 nm laser light guide system, or a 355 nm to 1064 nm picosecond laser and a 355 nm to 1064 nm laser light guide system, or a 355 nm to 1064 nm millisecond laser and a 355 nm to 1064 nm laser light guide system.

[0012] Furthermore, the laser liquid phase ablation treatment described in S3 is performed using a YAG high-energy laser (Spectra-Physics Laser), which is paired with a 532 nm nanosecond laser and a laser beam guiding system.

[0013] More preferably, in S3, the laser energy used in the pretreatment is 200~600mJ, the frequency is 10~50Hz, and the time is 5min~30min; the laser energy used in the laser ablation is 600mJ~1000mJ, the frequency is 10~50Hz, and the time is 15min~6h.

[0014] More preferably, in S3, the scanning mode of the galvanometer control system is full coverage or only outer diameter, the scanning trajectory is rectangular or circular (the trajectory size can be set according to the container size), and the scanning speed is 10mm / s to 100mm / s.

[0015] Furthermore, in S3, the trajectory of the galvanometer control system is set to an outer diameter circular trajectory with a trajectory radius of 5–50 mm and a scanning speed of 20–80 mm / s.

[0016] More preferably, S1 involves pulverizing the perfluorosulfonic acid resin solid particles to a particle size of millimeters by shearing or grinding.

[0017] More preferably, in S1, the volume of the added organic alcohol-water mixed solvent is 1.1 to 1.6 times that of the perfluorosulfonic acid resin dispersion of the target mass concentration.

[0018] More preferably, the mass concentration of the perfluorosulfonic acid resin dispersion is 5% to 20%, such as a series of perfluorosulfonic acid resin dispersion products with different specifications, such as 5%, 10%, 15%, and 20%.

[0019] More preferably, in step S1, the pulverized perfluorosulfonic acid resin solid particles are dispersed in an organic alcohol-water mixed solvent within a reaction vessel. The reaction vessel possesses high chemical stability, is compatible with the solvent and perfluorosulfonic acid resin, exhibits no chemical reaction, and prevents the leaching of impurities. The vessel also exhibits high tolerance to high-energy, high-frequency lasers and will not decompose or release particles due to laser irradiation. Furthermore, the reaction vessel has specific surface characteristics; its inner surface is as smooth as possible to facilitate material transfer and cleaning, preventing the adhesion of the high-concentration perfluorosulfonic acid resin dispersion.

[0020] More preferably, the homogenization device used in the homogenization process is a magnetic stirrer, a mechanical stirrer, or a high-speed separator.

[0021] The second aspect of the present invention also provides a perfluorosulfonic acid resin dispersion prepared by the method described in the first aspect.

[0022] The third aspect of this invention also provides the application of the perfluorosulfonic acid resin dispersion described in the second aspect in the fields of proton exchange membranes, catalyst coatings, and polymer material processing and treatment.

[0023] Compared with the prior art, the beneficial effects of the present invention are: This invention discloses a method for preparing perfluorosulfonic acid resin dispersions based on laser liquid-phase ablation technology. The method uses solid perfluorosulfonic acid resin particles as raw material. First, the particles are sheared and crushed into small particles using a mechanical crushing device. Then, the crushed particles are immersed in a specific ratio of organic alcohol-water mixed solution. A laser beam is controlled by a galvanometer control system to perform laser ablation on the perfluorosulfonic acid resin immersed in the solvent. The high temperature and high pressure effect generated by the laser in the liquid phase environment promotes the dissolution and dispersion of the solid perfluorosulfonic acid resin within the solvent. Simultaneously, a water-cooling device is used for thermal management of the system, supplemented by homogenization treatment, to ensure that the perfluorosulfonic acid resin dispersion prepared by the laser ablation reaction remains uniform during the preparation process and avoids denaturation. The final dispersion exhibits performance consistent with mature products in the industry and possesses excellent storage stability, making it widely applicable in fields such as proton exchange membrane preparation and catalyst coating preparation.

[0024] Specifically, the present invention has the following advantages: (1) The present invention implements system thermal management through water cooling device, supplemented by resin homogenization treatment, and relies on galvanometer control system for precise control, effectively overcoming the problem of heat accumulation and uneven energy distribution of resin during laser liquid phase ablation. (2) The method of the present invention has a simplified process, short time consumption, high efficiency and excellent integration. The preparation conditions are mild and production can be carried out under normal temperature and pressure. The equipment requirements are simple and can significantly reduce energy consumption and production costs, and realize continuous preparation. Among them, thermal management ensures that the reaction system is always in a suitable temperature range, homogenization treatment ensures that the perfluorosulfonic acid resin dispersion remains uniform during the preparation process, and the galvanometer control system realizes the uniform distribution and efficient utilization of laser energy. At the same time, by precisely controlling the laser parameters, the resin ablation process is ensured to be carried out within a safe window, and finally, the resin is efficiently dissolved while ensuring the integrity of the resin structure. (3) The present invention can flexibly adjust the type and amount of organic alcohol according to actual needs, thereby achieving precise control of the mass concentration of perfluorosulfonic acid resin dispersion. (4) The perfluorosulfonic acid resin dispersion prepared by the present invention based on laser liquid phase ablation technology has the application performance reaching the mature commercial standards of the industry, and at the same time has excellent storage stability.

[0025] In summary, this invention pioneered the use of laser-induced liquid-phase ablation technology to achieve rapid and environmentally friendly preparation of perfluorosulfonic acid resin dispersions under ambient temperature and pressure conditions. This technology leverages the rapid ablation effect induced by pulsed lasers in the liquid-phase environment to achieve efficient dissolution of perfluorosulfonic acid resins, overcoming the limitations of mainstream high-temperature and high-pressure preparation processes. It also boasts significant advantages such as precise controllability and continuous production, opening up a completely new technological path for the industrial production of perfluorosulfonic acid resin dispersions. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the equipment used in the embodiment; 1-laser, 2-high lens, 3-beam expander, 4-galvanometer control system, 5-galvanometer control module, 6-scanning galvanometer, 7-focusing field lens, 8-open reaction vessel, 9-magnetic stirrer, 10-magnetic stirrer, 11-water-cooled sleeve, 12-low-temperature cooling water circulation pump. The galvanometer control system 4 is composed of components such as the galvanometer control module 5 and the scanning galvanometer 6.

[0027] Figure 2 This is a schematic diagram illustrating the general workflow for preparing a perfluorosulfonic acid resin dispersion as an example.

[0028] Figure 3 The effect of laser scanning controlled by the galvanometer control system on the preparation of perfluorosulfonic acid resin dispersion is shown in Figure 1. (a) is the laser ablation effect of Comparative Example 1 using single-point laser action, and (b) is the laser ablation effect of Example 1 using the galvanometer control system.

[0029] Figure 4 The effect of applying an external temperature control system on the preparation of perfluorosulfonic acid resin dispersions is shown in Figure 2. (a) is the laser ablation effect of Comparative Example 2 without external temperature control, (b) is the laser ablation effect of Example 1 with external temperature control system at 20-25°C, and (c) is the laser ablation effect of Comparative Example 3 with external temperature control system at 10-15°C.

[0030] Figure 5 The Fourier transform infrared (FTIR) spectra of the 5% perfluorosulfonic acid resin dispersion prepared by laser liquid phase ablation technology under different laser parameters in Example 4 are compared with those of the LN05 dispersion prepared in Example 1.

[0031] Figure 6 The Fourier transform infrared (FTIR) spectra of the perfluorosulfonic acid resin dispersions (LN05, LN10) prepared by laser liquid phase ablation technology in Examples 1 and 2 and the commercial perfluorosulfonic acid resin dispersions are shown in the comparison diagram.

[0032] Figure 7 The Fourier transform infrared (FTIR) spectrum comparison of the perfluorosulfonic acid resin dispersion LN05 prepared by laser liquid phase ablation technology in Example 1 after standing for 1 month.

[0033] Figure 8 The figures show the micelle size statistics of perfluorosulfonic acid resin dispersions LN05 and LN10 prepared by laser liquid phase ablation technology in Examples 1 and 2, and commercial perfluorosulfonic acid resin dispersions; where (a) is the micelle size statistics of LN05, (b) is the micelle size statistics of LN10, and (c) is the micelle size statistics of commercial perfluorosulfonic acid resin dispersions.

[0034] Figure 9 This is a comparison chart of the IrO2 electrochemical oxygen evolution performance of the perfluorosulfonic acid resin dispersion LN05 prepared based on laser liquid phase ablation technology in Example 1 and a commercial perfluorosulfonic acid resin dispersion.

[0035] Figure 10 This is a comparison diagram of formate oxidation between the perfluorosulfonic acid resin dispersion LN05 prepared based on laser liquid phase ablation technology in Example 1 and a commercial perfluorosulfonic acid resin dispersion. Detailed Implementation

[0036] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0038] In this invention, the classification of laser energy and laser frequency is as follows: (1) Laser frequency: below 10Hz (excluding 10Hz) is classified as low frequency laser, 10 to 30Hz is classified as medium frequency laser, and above 30Hz (excluding 30Hz) is classified as high frequency laser; (2) Laser energy: below 400mj (excluding 400mj) is classified as low energy laser, 400 to 600mj is classified as medium energy laser, and above 600mj (excluding 600mj) is classified as high energy laser.

[0039] In the following embodiments, the laser light guiding system consists of four parts: a high-resolution lens, a beam expander, a galvanometer control system, and a focusing field lens. After the laser light is emitted from the laser, it is guided along the high-resolution lens, beam expander, galvanometer control system, and focusing field lens, ultimately acting on the material. The aforementioned laser light guiding system is a complete system purchased from Shaoke Laser Technology Co., Ltd.

[0040] In the following embodiments, the galvanometer control system in the laser beam guide system is a non-standard industrial customized galvanometer control system, including a customized high-reflectivity coated galvanometer and a galvanometer motion control program written in a programming language. The control of the galvanometer control system is realized by remote control by a control computer. Some standard accessories include: (1) scanning galvanometer, model: SCAN(532nm) P20XD201A; (2) galvanometer control module, model: MK-GMC-HANSCTR007A4; (3) switching power supply, model: HF150W-DL Hengfu; (4) 10M power signal line, model: SCANTXD-EW-02A5; the various components of the galvanometer control system operate as a whole system during the processing. The above-mentioned galvanometer control system is a complete system, assembled and provided by Shaoke Laser Technology Co., Ltd.

[0041] The galvanometer control system can control two aspects of the laser processing process: A. Control of laser scanning path: According to the preset program on the galvanometer control system, the laser focus can be controlled to perform spatial scanning along a preset geometric trajectory (such as rectangle or circle). It can perform scanning with only the outer diameter or full coverage as needed, so that the resin raw material can be uniformly melted under the action of laser. B. Control of laser scanning speed: The laser focus can be controlled to move along the above-mentioned path according to the preset program on the galvanometer control system, thereby directly regulating the residence time and energy input density of the laser on the resin.

[0042] The galvanometer control system aims to achieve the following process effects by controlling the laser scanning path and the laser scanning speed: A. The galvanometer control system controls the laser to perform dynamic scanning, so that the high-energy, high-frequency laser beam moves continuously in the material area, and the laser energy is evenly distributed in space and time. If the laser is statically and continuously focused on a point, it will cause extremely high heat accumulation in the action area. Even if a thermal management device and a homogenization device are introduced, the extremely high energy density and excessive heat accumulation will still cause irreversible chemical structure changes in the resin, resulting in oxidation, coking, and yellowing.

[0043] B. Improve laser energy utilization efficiency and ensure uniform resin ablation: The laser action controlled by the galvanometer control system enables the laser to act more uniformly on the surface of the resin raw material, increasing the interaction area between the laser and the resin, greatly improving the resin ablation efficiency, and giving the product dispersion better uniformity. C. Achieving process controllability: The setting of different scanning trajectories and different scanning processing speeds can meet the requirements for the preparation of perfluorosulfonic acid resin dispersions of different concentrations and scales.

[0044] In the following embodiments, the homogenization device consists of a magnetic stir bar and a magnetic stirrer. The magnetic stir bar is a B45 magnetic stir bar, model LG04-103-9B, brand Lige Youxuan; the magnetic stirrer is model 85-1, manufactured by Shanghai Yushen Instrument Co., Ltd.

[0045] In the following embodiments, the water-cooling device for thermal management of the system includes a water-cooled jacket (such as the liner of a hydrothermal synthesis reactor; model LC-KH-100PTFE, manufacturer: LICHEN) and a cryogenic cooling water circulation pump, model: CCA-20, manufacturer: Gongyi Yuhua Instrument Co., Ltd. The water-cooled jacket and the cryogenic cooling water circulation pump are connected by pipelines.

[0046] The schematic diagram of the equipment used in the following embodiments is shown below. Figure 1 As shown, the general workflow is as follows: Figure 2 As shown. The main workflow is as follows: (1) Put the resin, solvent and other raw materials into the open reaction vessel 8 and place the open reaction vessel 8 into the water-cooled sleeve 11 (such as the lining of the hydrothermal synthesis reactor); (2) Start the low temperature cooling water circulation pump 12 of the water-cooling device to apply the external temperature field, drive the cooling water in the water-cooled sleeve 11 to keep flowing continuously, and thus achieve precise control of the system temperature; (3) Irradiate the pretreated resin with high frequency laser. The pulsed laser is delivered according to the optical path arranged by the laser light guide system. The laser is emitted from the laser 1, passes through the high lens 2, the beam expander 3, the scanning galvanometer 6 and / or the focusing field lens (plano-convex lens) 7, and finally irradiates the open reaction vessel 8 containing the raw materials; (4) Start the homogenization device, which consists of a magnetic stir bar 9 and a magnetic stirrer 10; (5) During the homogenization process, the resin is ablated by high energy high frequency laser.

[0047] In the laser action of steps (3)-(5) above, the laser path is always controlled by the galvanometer control system 4. The galvanometer control system 4 is located directly above the open reaction vessel 8 and consists of components such as the scanning galvanometer 6, the galvanometer control module 5, and the focusing field mirror 7.

[0048] Example 1: A method for preparing a 5% (w / w) perfluorosulfonic acid resin dispersion (LN05) based on laser liquid phase ablation technology. The objective of this embodiment is to obtain 40 mL of a 5% (w / w) perfluorosulfonic acid resin dispersion (LN05). The specific steps are as follows: (1) Weigh 1.8 g of perfluorosulfonic acid resin solid particles (EW: 800) and place them in a ball mill, and ball mill them to the millimeter particle size; then transfer the ball-milled resin particles to an open container (i.e., the liner of the hydrothermal synthesis reactor in the water-cooling device), add 45 mL of n-propanol-water mixed solvent (n-propanol volume ratio is 70%), and mix thoroughly to form a homogeneous mixture; (2) A low-temperature cooling water circulation pump in the water-cooling device is used to apply an external temperature field to the mixing system in the open container to achieve thermal management. After the system temperature stabilizes at 20-25℃, a YAG high-energy laser from Spectra-Physics Laser (with a matching SGR type solid-state nanosecond laser, emitting a 532 nm pulsed laser) is used. After the optical path is controlled by the laser guide system, the laser is precisely applied to the raw material to perform liquid phase laser ablation treatment on the system. Specifically, the resin was pretreated by unfocused irradiation with a medium-energy, high-frequency laser without activating the homogenization device. The parameters were set to laser energy of 400 mJ, frequency of 50 Hz, and pretreatment time of 15 min. After pretreatment, the homogenization device was activated, and the rotation speed was adjusted to approximately 150 rpm. A 500 mm focal length focusing lens (plano-convex lens) was fixed 450 mm directly above the reaction vessel, switching the laser to a high-energy, high-frequency focused ablation mode for resin ablation. The parameters were adjusted to laser energy of 800 mJ, frequency of 50 Hz, and ablation time of 40 min. Throughout the laser irradiation and focused ablation processes, laser scanning control was implemented using a galvanometer control system. Based on the vessel specifications and resin feed rate, the galvanometer scanning trajectory was set to an outer diameter circular trajectory with a radius of 5 mm and a scanning speed of 40 mm / s. After high-energy laser liquid-phase ablation treatment, a 5% (by mass) perfluorosulfonic acid resin dispersion was obtained.

[0049] The two-step laser ablation operation in step (2) – “pretreatment with unfocused laser irradiation followed by focused laser ablation” – is performed because: when perfluorosulfonic acid resin solid particles come into contact with the organic alcohol-water mixed solvent, they quickly agglomerate into hard lumps. If the homogenization device (e.g., magnetic stirring) is started directly, the stir bar of the homogenization device will not operate normally. However, by first pretreating the resin particles with high-frequency laser irradiation, the hardening state can be alleviated, so that the stirring bar of the device can operate normally after the homogenization device is started, achieving homogenization and effective thermal management of the system in the subsequent ablation. In this way, after the first stage of laser irradiation pretreatment and system homogenization, the resin can be efficiently dissolved by high-energy high-frequency laser focused ablation.

[0050] Example 2: A method for preparing a 10% (w / w) perfluorosulfonic acid resin dispersion (LN10) based on laser liquid phase ablation technology. The objective of this embodiment is to obtain 40 mL of a 10% (w / w) perfluorosulfonic acid resin dispersion (LN10). The specific steps are as follows: (1) Weigh 3.6 g of perfluorosulfonic acid resin solid particles (EW: 800) and place them in a ball mill, and ball mill them to the millimeter particle size; then transfer the ball-milled resin particles to an open container (i.e., the liner of the hydrothermal synthesis reactor in the water-cooling device), add 45 mL of n-propanol-water mixed solvent (n-propanol volume ratio is 70%), and mix thoroughly to form a homogeneous mixture; (2) A low-temperature cooling water circulation pump in the water-cooling device is used to apply an external temperature field to the mixing system in the open container to achieve thermal management. After the system temperature stabilizes at 20-25℃, a YAG high-energy laser from Spectra-Physics Laser (with a matching SGR type solid-state nanosecond laser, emitting a 532 nm pulsed laser) is used. After the optical path is controlled by the laser guide system, the laser is precisely applied to the raw material to perform liquid phase laser ablation treatment on the system. Specifically, the resin was pretreated by unfocused irradiation with a medium-energy, high-frequency laser without activating the homogenization device. The parameters were set to a laser energy of 500 mJ, a frequency of 50 Hz, and a pretreatment time of 15 min. After pretreatment, the homogenization device was activated, and the rotation speed was adjusted to approximately 150 rpm. A focusing field lens with a focal length of 500 mm was fixed 450 mm directly above the reaction vessel. The process was then switched to a high-energy, high-frequency laser focused ablation mode for resin ablation. The laser parameters were adjusted to a laser energy of 1000 mJ, a frequency of 50 Hz, and an ablation time of 45 min. Throughout the laser irradiation and focused ablation processes, laser scanning control was implemented using a galvanometer control system. Based on the vessel specifications and resin feed rate, the galvanometer scanning trajectory was set to an outer diameter circular trajectory with a radius of 5 mm and a scanning speed of 50 mm / s. After high-energy laser liquid-phase ablation treatment, a perfluorosulfonic acid resin dispersion with a mass fraction of 20% was obtained.

[0051] Comparative Example 1: This comparative example is based on laser liquid phase ablation technology. It uses a single-point laser static action combined with a water cooling device to apply an external temperature field to prepare a 5% perfluorosulfonic acid resin dispersion.

[0052] Compared with Example 1, the difference is that in step (2), during the liquid phase laser ablation process, the galvanometer control system is not used to scan and control the laser, so that it always maintains a single-point static laser action. First, the resin is pretreated by medium-energy high-frequency laser unfocused irradiation without starting the homogenization device. The parameters are set as laser energy 400 mJ, frequency 50 Hz, and pretreatment time 15 min. After the pretreatment is completed, the homogenization device is started and switched to high-energy high-frequency laser focusing mode for resin ablation. The parameters are adjusted to laser energy 800 mJ and frequency 50 Hz. After the high-energy high-frequency laser ablates the resin for 1 min, the laser is paused to observe the resin state. It can be seen that the resin at the laser action point shows obvious scorching oxidation and denaturation phenomena, such as Figure 3 As shown in (a), in Example 1, a galvanometer control system was used to control the laser scanning, and the state of the ablated resin was as follows. Figure 3 As shown in (b), no obvious deformation was observed. It can be seen that because the laser continuously acts statically on a single point, heat continues to accumulate in the laser-affected area, resulting in excessively high temperature in the affected area, which ultimately leads to the resin oxidizing, turning yellow, or even charring and blackening.

[0053] Comparative Example 2: This comparative example is based on laser liquid phase ablation technology, using a galvanometer control system for regulation, but without applying an external temperature field to prepare a 5% perfluorosulfonic acid resin dispersion.

[0054] Compared with Example 1, the difference is that in step (2), during the liquid phase laser ablation process, a water-cooling device was not used to apply an external temperature field to the system for thermal management (i.e., a low-temperature cooling water circulation pump was not used to thermally manage the lining of the hydrothermal synthesis reactor). After the laser liquid phase ablation treatment, it was found that the perfluorosulfonic acid resin dispersion in this comparative example showed an overall yellowing phenomenon. Figure 4 As shown in (a), the dispersion of Example 1 is as follows: Figure 4 As shown in (b), no obvious deformation phenomenon was observed. It is speculated that the reason why the perfluorosulfonic acid resin dispersion in this comparative example turned yellow is that the heat generated by the continuous laser action could not be effectively and timely dissipated. Even with the introduction of a galvanometer control system to control the laser scanning, excessive heat accumulation in the laser action area still occurred, causing irreversible structural deformation of the perfluorosulfonic acid resin through oxidation and yellowing, ultimately resulting in the overall yellowing of the dispersion.

[0055] Comparative Example 3: This comparative example is based on laser liquid phase ablation technology, using a galvanometer control system for regulation, and combined with a water cooling device to apply an external temperature field to adjust the system temperature to below 20℃, to prepare a 5% perfluorosulfonic acid resin dispersion.

[0056] Compared with Example 1, the difference is that in step (2), the system temperature was stabilized at 10-15℃. After laser liquid phase ablation treatment was performed at the set temperature, it was found that the resin ablation efficiency was greatly reduced. Under the same ablation time of 40 min as in Example 1, more resin solid residue appeared in the dispersion, such as... Figure 4 As shown in (c). However, when the system temperature is too high, the heat generated by the laser cannot dissipate in time (see Comparative Example 2). Therefore, controlling the temperature range appropriately is key to ensuring efficient resin melting and product quality.

[0057] Comparative Example 4: This comparative example is based on laser liquid phase ablation technology. Different laser parameters were used to perform liquid phase laser ablation treatment to prepare a 5% perfluorosulfonic acid resin dispersion.

[0058] Step (1) is the same as in Example 1, but in this comparative example, three 1.8 g portions of perfluorosulfonic acid resin solid particles (EW: 800) are weighed.

[0059] Step (2) is basically the same as in Example 1, except that liquid phase laser ablation treatment with different laser parameters is applied to the three parts of perfluorosulfonic acid resin respectively: A. Under conditions where the homogenization device was not activated, the resin was initially pretreated using a medium-energy, high-frequency laser without focused irradiation. The parameters were set as follows: laser energy 400 mJ, frequency 50 Hz, and pretreatment time 15 min. After pretreatment, the homogenization device was activated, and the resin was ablated using a low-energy, high-frequency laser focused dissolution mode. The parameters were adjusted to laser energy 300 mJ and frequency 50 Hz. The experiment showed that the resin was completely ablated into a dispersion after 90 min of low-energy, high-frequency laser ablation. The resin dispersion obtained under condition A was named as control sample: LN05-Control Sample A.

[0060] B. Under conditions where the homogenization device was not activated, the resin was initially pretreated by unfocused irradiation with a medium-energy high-frequency laser. The parameters were set as follows: laser energy 400 mJ, frequency 50 Hz, and pretreatment time 15 min. After pretreatment, the homogenization device was activated, and the resin was ablated using the same medium-energy high-frequency laser, with the parameters adjusted to laser energy 600 mJ and frequency 50 Hz. The experiment showed that the resin was completely ablated into a dispersion after 60 min of medium-energy high-frequency laser ablation. The resin dispersion obtained under condition B was named as control sample: LN05-Control Sample B.

[0061] C. Under conditions where the homogenization device is not activated, a medium-energy high-frequency laser is used for preliminary pretreatment of the resin. The parameters are set as follows: laser energy 400 mJ, frequency 50 Hz, and pretreatment time 15 min. After pretreatment, the homogenization device is activated, and the resin is ablated using a high-energy low-frequency laser. The parameters are adjusted to laser energy 1000 mJ and frequency 10 Hz. The experiment showed that the resin was completely ablated into a dispersion after 30 min of high-energy low-frequency laser ablation. The resin dispersion obtained under condition C is named as control sample: LN05-Control Sample C.

[0062] Throughout the laser ablation process with the three different laser parameters described above, the laser was consistently controlled by a galvanometer control system. The galvanometer scanning trajectory was a circular trajectory with only the outer diameter, a radius of 5 mm, and a scanning speed of 40 mm / s. FTIR structural tests were performed on the LN05 samples from the three control samples and the example sample. The test results are as follows: Figure 5 As shown, the FTIR characteristic peaks of the three control samples are basically consistent with those of the examples, and the structures are basically the same, indicating that the magnitude of laser energy and the level of laser frequency mainly affect the speed of resin ablation efficiency.

[0063] Experimental Example 1: Characteristic Analysis of Perfluorosulfonic Acid Resin Dispersion The control used was a commercially available perfluorosulfonic acid resin dispersion, specifically a 5% Nafion dispersion manufactured by DuPont. This commercial product is a mature product in the industry, and its preparation process is the industry-leading "alcohol-water solvent high-temperature and high-pressure method," the publication number of the relevant patent: US4433082A.

[0064] (1) Fourier transform infrared (FTIR) analysis FTIR analysis was performed on the perfluorosulfonic acid resin dispersions (LN05, LN10) prepared in Examples 1 and 2, and on a commercially available perfluorosulfonic acid resin dispersion. The results are as follows: Figure 6 As shown. By Figure 6 As shown, the infrared absorption peaks of the three are highly consistent, mainly in the fingerprint area (1300–650 cm⁻¹). -1 The key peak positions are precisely matched, especially at 1230cm. -1 Characteristic absorption peak (CF2 stretching vibration) and 1050 cm⁻¹ -1 Characteristic absorption peaks (SO stretching vibration of the sulfonic acid group -SO3H). These precisely matching characteristic peaks indicate that after high-energy laser liquid-phase ablation treatment, the fluorocarbon backbone -CF2-CF2 and the sulfonic acid group -SO3H of the perfluorosulfonic acid resin are completely preserved, proving that the method of the present invention can strictly guarantee the structural integrity of the resin while promoting its full dissolution in the solvent. And in the functional group region 3500~3200 cm⁻¹... -1The characteristic absorption peaks of LN05 and LN20 show slight differences, which is attributed to the hydrogen bonding effect of the alcohol solvent in the dispersion. This is directly related to the type and content of the organic alcohol used, and not to any structural modification of the resin itself. Meanwhile, the peaks of LN05 and LN20 are highly consistent. This result further indicates that laser liquid phase ablation technology can effectively suppress resin modification and maintain its structural consistency within the 5–20% mass concentration range, thus confirming that the method of this invention possesses both excellent process stability and practical feasibility.

[0065] (2) Product storage stability verification The perfluorosulfonic acid resin dispersion LN05 prepared in Example 1 was stored in a dark environment at 15°C for one month. No sedimentation, stratification, or aggregation was observed in LN05; the macroscopic state of the dispersion remained uniform and transparent, exhibiting good flowability. Furthermore, FTIR structural testing of the dispersion after one month showed that its structure remained unchanged (e.g., ...). Figure 7 (As shown). This demonstrates that the perfluorosulfonic acid resin dispersion prepared using the method of the present invention can meet the basic requirements for practical storage and application.

[0066] (3) Micellar particle size test The samples LN05 and LN10 obtained in Examples 1 and 2, along with a commercially available perfluorosulfonic acid resin dispersion, were subjected to dynamic light scattering (DLS) testing using a Malvern Panalytical-Zetasizer Pro (UK). The test results are as follows: Figure 8 As shown, the micelle size of sample LN05 in the example is 182nm ± 0.6nm, and the polydispersity index (PI) is 0.086 ± 0.0002. Figure 8 a). The micelle size of the LN10 sample in the example was 227 nm ± 0.3 nm, and the polydispersity index (PI) was 0.11 ± 0.007 (a). Figure 8 b). The micelle size of the commercial control sample was 111 nm ± 0.4 nm, and the polydispersity index (PI) was 0.12 ± 0.005. Figure 8 c). The perfluorosulfonic acid resin dispersion prepared in this embodiment has a relatively large micelle size, but the micelle size distribution is narrow and the uniformity is good, which can also meet the requirements of practical applications.

[0067] Experimental Example 2: Verification of the Electrocatalytic Performance of Perfluorosulfonic Acid Resin Dispersion The control used was a commercially available perfluorosulfonic acid resin dispersion, specifically a 5% Nafion dispersion manufactured by DuPont. This commercial product is a mature product in the industry, and its preparation process is the industry-leading "alcohol-water solvent high-temperature and high-pressure method," which is covered by patent US4433082.

[0068] (1) Performance verification of oxygen evolution reaction (OER) The oxygen evolution reaction (OER) performance verification was conducted using a three-electrode system. The working electrode was a glassy carbon electrode, the counter electrode was a carbon rod, and the reference electrode was a mercury / mercury oxide reference electrode. The electrolyte was a 1M KOH solution.

[0069] Commercially available iridium black (Ir black) was selected as the catalyst for verification testing. 5 mg of Ir was weighed and prepared into a catalyst slurry with the following composition: 780 μL deionized water, 200 μL isopropanol, and 20 μL 5% Nafion dispersion. The selected 5% Nafion dispersions were LN05 and a commercially available 5% Nafion dispersion, named Ir-LN05 and Ir-c-nafion, respectively. After ultrasonically dispersing the slurry evenly, 5 μL was dropped onto the surface of a polished glassy carbon electrode (3 mm in diameter) and allowed to air dry at room temperature to obtain the working electrode.

[0070] The oxygen evolution reaction (OER) performance was tested in 1M KOH solution using linear voltammetry (LSV). The test results are as follows: Figure 9 As shown, the scan rate is 5 mV / s. From Figure 9 It can be seen that at 10mA / cm 2 The overpotential of the working electrode (Ir-LN05) prepared based on the LN05 dispersion was 293 mV, which is very close to the overpotential (298 mV) of the electrode (Ir-c-nafion) prepared using a commercial dispersion. These results indicate that the LN05 dispersion prepared using laser liquid phase ablation technology exhibits comparable performance in catalyst layer construction to commercial products in OER testing, demonstrating both excellent catalyst layer construction capability and electrochemical stability. This further verifies the feasibility and reliability of the method of this invention.

[0071] (2) Verification of the FAOR performance of formate oxidation The performance verification of FAOR oxidation of formate was carried out using a three-electrode system. The working electrode was a glassy carbon electrode, the counter electrode was a carbon rod, and the reference electrode was a silver / silver chloride reference electrode. The electrolyte was 1M KOH and 0.5M HCOOK solution.

[0072] Commercially available PdC was selected as the catalyst for verification testing. 5 mg of PdC was weighed and prepared into a catalyst slurry with the following composition: 780 μL deionized water, 200 μL isopropanol, and 20 μL 5% Nafion dispersion. The selected 5% Nafion dispersions were LN05 and a commercially available 5% Nafion dispersion, named PdC-LN05 and PdC-c-nafion, respectively. After ultrasonically dispersing the slurry evenly, 5 μL was dropped onto the surface of a polished glassy carbon electrode (3 mm in diameter) and allowed to air dry at room temperature to obtain the working electrode.

[0073] The formate oxidation FAOR performance was tested using linear voltammetry (LSV) in 1M KOH and 0.5M HCOOK solutions. The test results are as follows: Figure 10 As shown, the scan rate is 5 mV / s. From Figure 10 It can be seen that the curves of PdC-LN05 and PdC-c-nafion are similar. Among them, at a voltage of 0.62 V, the peak current of PdC-LN05 is... The peak current of PdC-c-nafion is The above results indicate that the dispersion LN05 prepared based on laser liquid phase ablation technology exhibits comparable catalyst layer construction performance to commercial products in FAOR tests, demonstrating both excellent catalyst layer construction capability and electrochemical stability. This further verifies the feasibility and reliability of the method of this invention.

[0074] In summary, this invention achieves efficient and rapid mass production of perfluorosulfonic acid resin dispersions at room temperature and pressure by using laser liquid phase ablation, employing a galvanometer control system to control the laser during processing, using a water-cooling device for thermal management of the system, and using a homogenizer to homogenize the perfluorosulfonic acid resin. This results in a dispersion product with performance consistent with mature products in the industry and good storage stability, significantly reducing energy consumption and production costs.

[0075] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology, characterized in that, Perfluorosulfonic acid resin solid particles were dispersed in an organic alcohol-water mixed solvent using perfluorosulfonic acid resin solid particles as raw material. The laser path was precisely controlled by a galvanometer control system, and a water-cooling device was used for system thermal management to ensure that the system temperature was maintained stably within the range of 20-25°C. Based on this, a stepwise laser ablation process was used to treat the perfluorosulfonic acid resin in the system: first, the resin particles were irradiated and pretreated using a non-focused low-to-medium energy medium-to-high frequency laser; then, the pretreated resin was homogenized and controlled, and the laser was switched to a medium-to-high energy medium-to-high frequency laser focusing ablation mode to deeply ablate the resin. With the help of the high temperature and high pressure local environment formed when the laser acts on the liquid phase, the perfluorosulfonic acid resin solid particles were efficiently dissolved and dispersed in the mixed solvent, and finally a stable perfluorosulfonic acid resin dispersion was obtained.

2. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology according to claim 1, characterized in that, Includes the following steps: S1. Pulverize the perfluorosulfonic acid resin solid particles to millimeter-sized particles, and then disperse them in an organic alcohol-water mixed solvent; S2. Apply an external temperature field to the mixed system in S1 using a water cooling device to achieve thermal management, so that the temperature of the system is stabilized at 20-25℃ during the subsequent laser liquid phase ablation process. S3. Under the condition of laser scanning control implemented by the galvanometer control system, the resin in the mixed solvent is subjected to laser liquid phase ablation treatment: first, the resin in the mixed solvent is pretreated by low-to-medium energy medium-to-high frequency laser non-focused irradiation, then the pretreated resin is homogenized, and then the pretreated resin is ablated by switching to medium-to-high energy medium-to-high frequency laser focusing mode; then the perfluorosulfonic acid resin is dissolved under the action of high-energy focused laser ablation to form a perfluorosulfonic acid resin dispersion.

3. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology according to claim 2, characterized in that, The EW of the perfluorosulfonic acid resin solid particles is 800-1100.

4. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid phase laser ablation technology according to claim 2, characterized in that, The organic alcohol used in the organic alcohol-water mixed solvent is n-propanol, isopropanol, or ethanol, and the volume content of the organic alcohol is 40-80%.

5. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology according to claim 2, characterized in that, The laser liquid phase ablation treatment described in S3 is performed using a YAG high-energy laser, which is paired with a 355 nm to 1064 nm nanosecond laser and a 355 nm to 1064 nm laser light guide system, or a 355 nm to 1064 nm picosecond laser and a 355 nm to 1064 nm laser light guide system, or a 355 nm to 1064 nm millisecond laser and a 355 nm to 1064 nm laser light guide system.

6. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology according to claim 2, characterized in that, In S3, the laser energy used for pretreatment is 200~600mJ, the frequency is 10~50Hz, and the time is 5min~30min; the laser energy used for laser focused ablation is 600mJ~1000mJ, the frequency is 10~50Hz, and the time is 15min~6h.

7. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid phase laser ablation technology according to claim 2, characterized in that, In S3, the scanning mode of the galvanometer control system is either full coverage or outer diameter only, the scanning trajectory is rectangular or circular, and the scanning speed is 10mm / s to 100mm / s.

8. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid phase laser ablation technology according to claim 2, characterized in that, S1 involves pulverizing perfluorosulfonic acid resin solid particles to millimeter-scale size through shearing or grinding.

9. The method for preparing a perfluorosulfonic acid resin dispersion based on liquid-phase laser ablation technology according to claim 2, characterized in that, The mass concentration of the perfluorosulfonic acid resin dispersion is 5% to 20%.

10. A perfluorosulfonic acid resin dispersion prepared by the method according to any one of claims 1 to 9.

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