A high-precision directional irradiation grafting method for material surfaces based on synchrotron radiation

Abstract

This invention provides a high-precision directional irradiation grafting method for material surfaces based on synchrotron radiation. The method includes: S1: constructing a high-precision directional irradiation grafting system, which includes a KB mirror, a four-slit assembly, an attenuation assembly, and a sample control assembly arranged sequentially along an axis via a vacuum conduit; S2: using the high-precision directional irradiation grafting system in conjunction with a synchrotron radiation scattering beamline system to confine the photon beam to an extremely small spatial range, thereby achieving precise micron-level directional irradiation of the material surface based on synchrotron radiation. Based on existing synchrotron radiation scattering beamline equipment, this invention constructs a high-precision directional irradiation grafting system using a KB mirror, a four-slit assembly, an attenuation assembly, and a sample control assembly. When used in conjunction with a synchrotron radiation scattering beamline system, it meets the requirements for localized customization, such as crosslinking area, crosslinking dose rate, and crosslinking type, thus showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of irradiation grafting of material surfaces, and more specifically to a high-precision directional irradiation grafting method for material surfaces based on synchrotron radiation. Background Technology

[0002] Radiation-induced surface grafting is an important technique in polymer processing. Polymers absorb ionizing radiation energy, triggering a series of chemical reactions through ionization, excitation, and initiation. The radiation effects on polymers mainly include radiation crosslinking, radiation cracking, changes in the content of unsaturated bonds, and the generation of trapped free radicals. These changes lead to alterations in the physical properties of the polymer material. Because polymer molecules are composed of thousands or even tens of thousands of monomer units, even small chemical changes induced by radiation can cause significant changes in the physical and mechanical properties of the polymer. Therefore, it is widely used in important fields such as wires and cables, and artificial joints. However, currently, due to equipment limitations, it is not possible to perform customized irradiation grafting on a small area within a sample.

[0003] Currently, mainstream technologies mainly focus on functionalized irradiation grafting routes targeting different materials, resulting in limited applicability to a single sample. For example, CN201910505531.9 "A method for preparing antibacterial fabrics based on gamma-ray irradiation grafting technology" and CN201910482720.9 "A method for preparing lignin adsorbents by irradiation grafting" are specific to their respective materials. On the other hand, invention patents such as CN202311662315.8 "Anion and cation irradiation grafting modified perfluorosulfonic acid ion exchange membrane and its preparation method and application," CN201510238937.7 "A method for preparing polypropylene toughening modifiers by irradiation grafting," and CN202010177732.3 "An irradiation grafting modification method for cotton fabrics" utilize ion beams, gamma rays, and electron beams for irradiation grafting, respectively; no cases of synchrotron radiation grafting have been found. Furthermore, there are no reports of high-precision irradiation grafting in existing technologies. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision directional irradiation grafting method for material surfaces based on synchrotron radiation, thereby solving the problem that the prior art lacks a method for localized customized irradiation grafting of materials.

[0005] To solve the above problems, the present invention adopts the following technical solution:

[0006] A method for high-precision directional irradiation grafting of material surfaces based on synchrotron radiation is provided. The method includes: S1: constructing a high-precision directional irradiation grafting system, which includes: a KB mirror, a four-blade slit assembly, an attenuation assembly, and a sample control assembly arranged sequentially along an axis by a vacuum pipe; S2: using the high-precision directional irradiation grafting system in conjunction with a synchrotron radiation scattering beamline system to confine the photon beam to an extremely small spatial range, thereby achieving precise micron-level directional irradiation of the material surface based on synchrotron radiation.

[0007] According to the present invention, the method can focus the synchrotron radiation light to a micrometer by using the KB mirror.

[0008] According to the present invention, the method controls the shape of the light spot through the four-blade slit assembly.

[0009] According to the present invention, the method controls the irradiation dose by adjusting the attenuation component and changing the irradiation time.

[0010] According to the present invention, the method places and moves the sample by means of the sample control assembly, so that the beam irradiates the desired area.

[0011] Preferably, the high-precision directional irradiation grafting system further includes a scattering detector, which is used to monitor the shape of the light spot and the grafting reaction online.

[0012] According to the present invention, the grafting range of the method is adjustable, and the size of the grafting area is at the micrometer or submicrometer level.

[0013] According to the present invention, the synchrotron radiation scattering beamline system is the Shanghai Synchrotron Radiation Scattering Beamline System.

[0014] Traditional irradiation sources, such as electron accelerators and Co sources, irradiate radially. If common physical shielding methods are used to concentrate the radiation area, drawbacks include low dose rates, difficulty in controlling the irradiated area, and activation of the shielding equipment. Using ordinary X-ray aging machines as the radiation source results in insufficient dose rates and low precision. However, thanks to the high-throughput (significantly higher than commercially available X-ray machines) and highly collimated synchrotron radiation from the Shanghai Synchrotron Radiation Facility, the irradiation spot can be focused to micrometers using a KB mirror. The spot shape is then controlled by a four-slit assembly, the dose is controlled by attenuation components and irradiation time, and the irradiation position is controlled by the sample stage system. This achieves precise micrometer-level irradiation crosslinking control without affecting surrounding areas that do not require irradiation.

[0015] This invention is applicable to a wide range of samples, including all irradiable graftable materials, such as ultra-high molecular weight polyethylene (UHMWPE), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyimide (PI), polypropylene (PP), and other polymer materials, as well as some natural polymer materials such as silk protein and cellulose.

[0016] The underlying scientific principle of this invention is to utilize the particle characteristics of high-flux photons in synchrotron radiation and employ a series of control systems to confine the photon beam to an extremely small spatial range (micrometer scale). While not affecting the photon flux or having a minimal impact on the photon flux, the sample is bombarded, inducing the material to generate free radicals, which in turn triggers an irradiation grafting reaction on the sample surface.

[0017] It should be understood that the KB mirror, four-slit assembly, attenuation assembly, and sample control assembly are all commercially available devices or have been disclosed in patent applications, and are therefore prior art. Specifically, the KB mirror can be found in Chinese invention patent CN201910062560.2. The KB mirror's function is to confine a large photon beam to a smaller spatial area while minimizing its impact on beam flux. The four-slit assembly further reduces the projected area of ​​the beam, and this system does affect beam flux. The attenuation assembly uses different numbers of attenuator layers to match the beam flux (irradiated absorbed dose rate) to the dose rates of different samples and irradiation grafting reactions, achieving a reasonable range. The sample control assembly is used to place and move the sample, ensuring the beam irradiates the required area. The scattering detector monitors the spot shape and grafting reaction online.

[0018] The main inventive point of this invention lies in utilizing the high collimation and high brightness characteristics of synchrotron radiation. By using a KB mirror, a four-blade slit assembly, an attenuation assembly, and a sample control console, the size and energy of the irradiation spot can be adjusted. Without changing the overall structure of the material, it adapts to the micron-scale precise directional irradiation grafting effect on the sample surface. Through the combination of existing equipment, it creatively realizes precise irradiation grafting on the micron-scale of the material surface, especially meeting the needs of local customization, such as the crosslinking area, crosslinking dose rate, and crosslinking type of irradiation grafting.

[0019] In summary, this invention, based on existing equipment at synchrotron radiation scattering beamlines, constructs a high-precision directional irradiation grafting system using a KB mirror, a four-blade slit assembly, an attenuation assembly, and a sample control assembly. When used in conjunction with the synchrotron radiation scattering beamline system, it confines the photon beam to an extremely small spatial range, thereby achieving precise micron-level directional irradiation of material surfaces based on synchrotron radiation without affecting surrounding areas that do not require irradiation. This system possesses high scientific research value and promising application prospects. Attached Figure Description

[0020] Figure 1This is a schematic diagram of a high-precision directional irradiation grafting system based on a synchrotron radiation scattering beamline according to the present invention.

[0021] Figure 2 This is a diagram showing the change in surface contact angle of the sample in Example 1 before and after irradiation grafting treatment using the method of the present invention;

[0022] Figure 3 The free radical ESR signal spectrum of the sample in Example 1 after irradiation grafting treatment by the method of the present invention;

[0023] Figure 4 The images shown are FTIR infrared scans of the sample in Example 1 before and after irradiation grafting treatment using the method of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, the techniques used in the embodiments are conventional practices in the art, or experimental methods recommended by the instrument manufacturer. Unless otherwise specified, the reagents and materials used in the embodiments are commercially available.

[0025] Three-dimensional ultra-high molecular weight polyethylene (UHMWPE) has long been the preferred choice for bio-implants such as acetabular liners and tibial inserts. UHMWPE has been used in clinical medicine since 1998, and early medical studies showed that cross-linked UHMWPE has a significantly lower wear rate than conventional UHMWPE. Therefore, cross-linked UHMWPE has become the primary choice for weight-bearing and joint contact components in total arthroplasty. However, microparticle debris (peripheral prosthesis osteolysis) caused by bone resorption around the implant remains a major factor limiting the long-term service life of artificial joints. Generally, artificial joints can be used continuously for 15-25 years. However, if "long-term failure" occurs, the implant's lifespan may be less than 5 years. Furthermore, in addition to higher costs, the severely shortened service life of artificial joints means that patients may suffer secondary damage and pain during reimplantation. Surface lubrication modification of stress concentration points (major wear points, micron-level) in three-dimensional UHMWPE materials can help address this problem. However, the chemical inertness of UHMWPE hinders grafting to some extent.

[0026] Example 1: Construction of a high-precision directional irradiation grafting system

[0027] like Figure 1 As shown, in existing synchrotron radiation scattering beamline systems (such as...) Figure 1Based on the example shown on the left, this embodiment constructs a high-precision directional irradiation grafting system (as shown on the left) for use in conjunction with a synchrotron radiation scattering beamline system. Figure 1 As shown on the right side of the middle section, the high-precision directional irradiation grafting system includes: a KB mirror, a four-slit assembly, an attenuation assembly, a sample control assembly, and a scattering detector. The KB mirror, the four-slit assembly, the attenuation assembly, the sample control assembly, and the scattering detector are connected by vacuum pipes and arranged sequentially along an axis.

[0028] The KB mirror confines a large photon beam to a smaller spatial area with minimal impact on beam flux. The four-slit assembly further reduces the projected area of ​​the beam (this system affects beam flux). The attenuation assembly uses different layers of attenuators to match the beam flux (irradiated absorbed dose rate) to the dose rates of different samples and irradiation grafting reactions, achieving a reasonable range. The sample control assembly positions and moves the sample to ensure the beam irradiates the desired area. The scattering detector monitors the spot shape and grafting reaction online.

[0029] Example 2: High-precision directional irradiation grafting on the surface of three-dimensional ultra-high molecular weight polyethylene material

[0030] Includes the following steps:

[0031] 1) According to Figure 1 As shown, behind the existing synchrotron radiation scattering beamline system, the KB mirror, four-blade slit assembly, attenuation assembly, sample control assembly, and scattering detector are placed sequentially in the optical path, and the relevant equipment is adjusted so that the optical path can reach the sample stage in a straight line and perpendicularly.

[0032] 2) Place the UHMWPE film on the sample stage of the sample control assembly. Focus the irradiation spot to a micrometer using the KB lens. Then, control the spot shape using the subsequent four-slit assembly. Control the irradiation dose by using the attenuation assembly and changing the irradiation time. Control the irradiation position using the sample stage system and start the irradiation exposure.

[0033] 3) Control the exposure time, such as 20 min, 40 min, or 60 min. After that, remove the sample and immerse it in acrylic solution for 2 hours.

[0034] 4) Remove the sample and perform relevant characterization. Alternatively, use surface-grafted acrylic acid as a bridge to further bind relevant substances, such as silver (antibacterial) and copper.

[0035] The reaction mechanism of this irradiation grafting involves high-flux synchrotron radiation striking the UHMWPE material, causing the C-C and C-H covalent bonds in the UHMWPE material to break, forming free radicals (such as alkyl free radicals). The generated free radicals then combine with cross-linking substances (such as acrylic acid in the example). This mechanism has been applied in electron beams and gamma rays, so this article will only provide a brief explanation for ease of understanding.

[0036] UHMWPE material has poor hydrophilicity, so grafting with acrylic acid (a hydrophilic material) improves its hydrophilicity. Figure 2 As shown, the contact angle of the material surface changed significantly before and after irradiation grafting treatment using the method of the present invention. This proves that the grafting method of the present invention is successful, and the grafting amount increases with time.

[0037] The free radical ESR signal spectrum after irradiation grafting treatment using the method of this invention is shown below. Figure 3 As shown, the ESR signal reflects the type of free radicals, and this is a typical alkyl free radical signal. This indicates that the method successfully induced the generation of free radicals in the UHMWPE material.

[0038] The FTIR infrared scan image after irradiation grafting treatment using the method of this invention is shown below. Figure 4 As shown, the Fourier Transform Infrared (FTIR) surface scan confirms that the grafted region is on the micrometer scale, and the test peak is located at 1716 cm⁻¹ where C=O is located. -1 At this location, the characteristic peak of acrylic acid is visible below the beam. The upper image shows the area before irradiation, where no obvious characteristic peak is visible. The lower image shows the surface scan after irradiation, where a distinct infrared characteristic region (red) can be seen. This region is consistent with the shape of the light spot (blue in the middle), thus proving that this method has successfully performed micron-level precision irradiation grafting.

[0039] In summary, acrylic acid was successfully grafted onto the surface of UHMWPE using the high-precision directional irradiation grafting method provided by this invention.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. All simple and equivalent changes and modifications made in accordance with the claims and description of this application fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A high-precision directional irradiation grafting method for material surfaces based on synchrotron radiation, characterized in that, The method includes: S1: Construct a high-precision directional irradiation grafting system, comprising: a KB mirror, a four-slit assembly, an attenuation assembly, and a sample control assembly arranged sequentially along an axis via a vacuum conduit; focusing synchrotron radiation light using the KB mirror to narrow the irradiated spot to micrometers; controlling the spot shape using the four-slit assembly; and controlling the irradiation dose by adjusting the attenuation assembly and changing the irradiation time. S2: The high-precision directional irradiation grafting system is used in conjunction with the synchrotron radiation scattering beamline system to confine the photon beam to an extremely small spatial range, thereby achieving precise micron-level directional irradiation of the material surface based on synchrotron radiation. While not affecting the photon flux or having a minimal impact on the photon flux, the sample is bombarded, inducing the material to generate free radicals, which in turn triggers the irradiation grafting reaction on the sample surface, allowing the generated free radicals to combine with the cross-linking material. The synchrotron radiation scattering beamline system is the Shanghai Synchrotron Radiation Facility scattering beamline system.

2. The high-precision directional irradiation grafting method for material surfaces according to claim 1, characterized in that, The method uses the sample control component to place and move the sample, thereby irradiating the desired area with a beam.

3. The high-precision directional irradiation grafting method for material surfaces according to claim 1, characterized in that, The high-precision directional irradiation grafting system also includes a scattering detector, which is used to monitor the shape of the light spot and the grafting reaction online.

4. The high-precision directional irradiation grafting method for material surfaces according to claim 1, characterized in that, The grafting range of the method is adjustable, and the size of the grafting area is in the micrometer or submicrometer range.

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