Material surface high-precision directional irradiation grafting method based on synchrotron radiation

Abstract

The invention provides a material surface high-precision directional irradiation grafting method based on synchrotron radiation, and the method comprises the steps: S1, constructing a high-precision directional irradiation grafting system which comprises a KB mirror, a four-knife slit assembly, an attenuation assembly and a sample control assembly which are connected through a vacuum pipeline and are sequentially arranged along an axis; s2, the high-precision directional irradiation grafting system is used in cooperation with a synchrotron radiation scattered ray station system, photon beams are restrained to be within a very small space range, and then precise micron-order directional irradiation based on synchrotron radiation is achieved on the surface of the material. On the basis of the existing equipment of the synchrotron radiation scattered ray station, the high-precision directional irradiation grafting system is constructed through the KB mirror, the four-knife slit assembly, the attenuation assembly and the sample control assembly, and is matched with a synchrotron radiation scattered ray station system for use, so that the irradiation grafting requirements of local customization such as crosslinking area, crosslinking dosage rate and crosslinking type are met, and the irradiation grafting efficiency is improved. Therefore, the method has a good application prospect.

Description

Technical Field

[0001] The invention relates to the field of material surface radiation grafting, and more specifically to a material surface high-precision directional radiation grafting method based on synchrotron radiation. Background Art

[0002] Radiation surface grafting is an important means of polymer processing. The polymer absorbs ionizing radiation energy and undergoes a series of chemical reactions through ionization, excitation and initiation. The radiation effects of polymers mainly include radiation crosslinking, radiation cracking, changes in the content of unsaturated bonds, and the generation of some trapped free radicals. These changes lead to changes in the physical properties of polymer materials. Since polymer molecules are composed of thousands or even tens of thousands of monomer units, small chemical changes induced by radiation can cause significant changes in the physical properties of polymers, and small chemical changes can cause significant changes in the physical and mechanical properties of polymers. Therefore, it is also widely used in important fields such as wires and cables, artificial joints, etc. However, at present, due to the characteristics of the equipment, it is impossible to perform customized radiation grafting on small areas in a sample.

[0003] At present, the mainstream technology is mainly the functionalized irradiation grafting route for irradiation grafting of different materials, and its applicability to samples is single, such as CN201910505531.9 "A method for preparing antibacterial fabrics based on γ-ray irradiation grafting technology", CN201910482720.9 "A method for preparing lignin adsorbent by irradiation grafting", etc., which are only characterized by the corresponding materials. On the other hand, the invention patents CN202311662315.8 "A perfluorosulfonic acid ion exchange membrane modified by irradiation grafting of anions and cations and its preparation method and application", CN201510238937.7 "A method for preparing polypropylene toughening modifier by irradiation grafting", and CN202010177732.3 "A method for irradiation grafting modification of cotton fabrics" respectively use ion beams, gamma rays, and electron beams for irradiation grafting, and no related cases of synchrotron radiation grafting have been found. There has been no report on high-precision irradiation grafting in the prior art. Summary of the invention

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

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] Provided is a method for high-precision directional irradiation grafting of a material surface based on synchrotron radiation, the method comprising: S1: constructing a high-precision directional irradiation grafting system, which comprises: a KB mirror, a four-blade slit assembly, an attenuation assembly and a sample control assembly connected in sequence along an axis by a vacuum pipe; S2: using the high-precision directional irradiation grafting system in conjunction with a synchrotron radiation scattering beam station system to constrain a photon beam to a very 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 focuses the synchrotron radiation light through the KB mirror, and can converge the irradiation spot to micrometers.

[0008] According to the present invention, the method controls the light spot shape 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 through the sample control component so that the beam irradiates to a required range.

[0011] Preferably, the high-precision directional irradiation grafting system further comprises a scattering detector, which functions to monitor the light spot shape 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 micron-sized or submicron-sized.

[0013] According to the present invention, the synchrotron radiation scattering beam station system is the Shanghai Light Source synchrotron radiation scattering beam station system.

[0014] Traditional radiation sources such as electron accelerators and Co sources are all radial irradiation. If the common physical shielding method is used to converge the radiation area, there will be defects such as low radiation dose rate, difficult to control the radiation area, and activation of shielding equipment. If an ordinary X-ray aging machine is used as a radiation source, the dose rate will be insufficient and the accuracy will not be high. However, thanks to the high-flux (the light flux is much greater than that of X-ray machines on the market) and highly collimated synchrotron radiation light of the Shanghai Synchrotron Radiation Source, the irradiation spot can be focused to microns through the KB mirror, and the spot shape is controlled by the subsequent four-blade slit assembly. The irradiation dose is controlled by the attenuation component and changing the irradiation time, and the irradiation position is controlled by the sample stage system, achieving precise micron-level irradiation cross-linking control without affecting the surrounding areas that do not need to be irradiated.

[0015] The present invention is applicable to a wide range of samples, and is applicable to all materials that can be irradiated and grafted, including ultra-high molecular weight polyethylene (UHMWPE), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyimide (PI), polypropylene (PP) and other polymer materials, and also includes some natural polymer materials such as silk protein, cellulose and the like.

[0016] The underlying scientific principle of the present invention is to utilize the particle characteristics of high-flux photons in synchrotron radiation and adopt a series of control systems to confine the photon beam to an extremely small spatial range (micrometer level), bombard the sample without affecting the photon flux or with little impact on the photon flux, induce the material to produce free radicals, and then trigger the radiation grafting reaction on the sample surface.

[0017] It should be understood that the KB mirror, four-blade slit assembly, attenuation assembly and sample control assembly are all commercial equipment or have been disclosed in patent applications and belong to the prior art. Among them, the KB mirror can be specifically referred to in Chinese invention patent CN201910062560.2. The function of the KB mirror is to constrain a larger photon beam to a smaller spatial range with less impact on the beam flux. The four-blade slit assembly is to further cut the projection area of ​​the beam to further reduce it, and this system will affect the beam flux. The function of the attenuation assembly is to match the beam flux (irradiation absorption dose rate) of different samples and different irradiation grafting reactions by adding different layers of attenuation sheets to a reasonable range. The function of the sample control assembly is to place and move the sample so that the beam is irradiated to the required range. The function of the scattering detector is to monitor the spot shape online and monitor the grafting reaction.

[0018] The main inventive point of the present invention is that the high collimation and high brightness characteristics of synchrotron radiation are utilized, and the irradiation spot size and energy are adjustable through the KB mirror, the four-knife slit assembly, the attenuation assembly, and the sample control console. Without changing the overall structure of the material, the micron-level precise directional irradiation grafting effect on the surface of the sample is adapted. Through the combination of existing equipment, the precise irradiation grafting on the micron scale of the material surface is creatively realized, especially meeting the local customization, such as the irradiation grafting requirements of the cross-linking area, the cross-linking dose rate, and the cross-linking type.

[0019] In summary, based on the existing equipment of the synchrotron radiation scattering beam station, the present invention constructs a high-precision directional irradiation grafting system through the KB mirror, the four-knife slit assembly, the attenuation assembly and the sample control assembly. When used in conjunction with the synchrotron radiation scattering beam station system, the photon beam is constrained to an extremely small spatial range, thereby realizing precise micron-level directional irradiation of the material surface based on synchrotron radiation without affecting the surrounding areas that do not need to be irradiated. The system has high scientific research value and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A schematic diagram of a high-precision directional irradiation grafting system based on a synchrotron radiation scattering beam station according to the present invention;

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

[0022] Figure 3 This is a free radical ESR signal spectrum of the sample in Example 1 after being irradiated and grafted by the method of the present invention;

[0023] Figure 4 FTIR infrared scans of the sample in Example 1 before and after irradiation grafting treatment by the method of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. Unless otherwise specified, the technical means used in the examples are conventional operations in the art, or according to the experimental methods recommended by the instrument and equipment manufacturers. The reagents and materials used in the examples can be obtained from commercial sources unless otherwise specified.

[0025] Three-dimensional ultra-high molecular weight polyethylene (UHMWPE) materials have always been the best choice for bioimplants such as acetabular liners and tibial inserts. UHMWPE has been used in medical clinical treatment since 1998, and early medical studies have shown that the wear rate of cross-linked UHMWPE is significantly lower than that of conventional UHMWPE. Therefore, cross-linked UHMWPE has become the main choice for load-bearing and joint contact components in total joint replacement. However, particulate debris caused by bone resorption around the implant (periprosthetic osteolysis) is still the main factor limiting the long-term service of artificial joints. Generally speaking, artificial joints can be used continuously for 15-25 years. However, if "long-term failure" occurs, the service life of the implant may be less than 5 years. In addition, in addition to higher costs, the severely shortened service life of artificial joints also means that patients may suffer secondary damage and pain when re-implanted. Surface lubrication modification of stress concentration points (main wear points, micrometer level) of three-dimensional UHMWPE materials will help solve this problem. However, the chemical inertness of UHMWPE hinders the grafting to a certain extent.

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

[0027] like Figure 1 As shown in the existing synchrotron radiation scattering beam station system (such as Figure 1Based on the left side of the figure, this embodiment constructs a high-precision directional irradiation grafting system (as shown in FIG. Figure 1 As shown on the right side of the figure, the high-precision directional irradiation grafting system includes: a KB mirror, a four-knife slit assembly, an attenuation assembly, a sample control assembly, and a scattering detector, wherein the KB mirror, the four-knife slit assembly, the attenuation assembly, the sample control assembly, and the scattering detector are connected by a vacuum pipe and are arranged in sequence along an axis.

[0028] The function of the KB mirror is to constrain a larger photon beam to a smaller spatial range with less impact on the beam flux. The four-blade slit assembly is to further cut the projection area of ​​the beam to further reduce it (the system will affect the beam flux). The attenuation assembly is to add different layers of attenuation sheets to match the beam flux (irradiation absorption dose rate) of different samples and different irradiation grafting reactions to a reasonable range. The sample control assembly is used to place and move samples so that the beam irradiates to the required range. The scattering detector is used to monitor the spot shape and grafting reaction online.

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

[0030] The following steps are involved:

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

[0032] 2) Place the UHMWPE film on the sample stage of the sample control component. Through the KB mirror focusing, the irradiation spot can be converged to microns. Then the spot shape is controlled by the subsequent four-blade slit component. The irradiation dose is controlled by the attenuation component and changing the irradiation time. The irradiation position is controlled by the sample stage system, and the irradiation exposure begins.

[0033] 3) Control the exposure time, such as 20min, 40min, 60min. Then remove the sample and soak it in acrylic acid solution for 2 hours.

[0034] 4) Take out the sample and conduct relevant characterization. Or use the surface grafted acrylic acid as a bridge to further combine related substances, such as silver (antibacterial), copper, etc.

[0035] The reaction mechanism of the irradiation grafting is that high-flux synchrotron radiation strikes the UHMWPE material, breaking the C-C and C-H covalent bonds in the UHMWPE material to form free radicals (such as alkyl free radicals), which then combine with cross-linking substances (such as acrylic acid in the example). This mechanism has been applied to electron beams and gamma rays, so this article only gives a brief explanation for easy understanding.

[0036] UHMWPE material is not very hydrophilic, so after grafting acrylic acid (hydrophilic material), the hydrophilicity of the material is improved. Figure 2 As shown, the contact angle of the material surface changes significantly before and after the irradiation grafting treatment by the method of the present invention, which proves that the grafting by the 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 by the method of the present invention is as follows Figure 3 As shown in the figure, the ESR signal reflects the type of free radicals, which is a typical alkyl free radical signal. This shows that this method successfully triggered the generation of free radicals in UHMWPE materials.

[0038] The FTIR infrared scanning image after the irradiation grafting treatment by the method of the present invention is as follows Figure 4 As shown, the FTIR scan proves that the grafting area is micrometer-sized, and the test peak is 1716 cm where C=O is located. -1 The characteristic peak of acrylic acid is under this beam. The upper picture is before irradiation, and it can be seen that there is no obvious characteristic peak at this place. The lower picture is the surface scan after irradiation, and an obvious infrared characteristic area (red) can be seen. This area is consistent with the shape of the light spot (the middle blue picture), which proves that this method has successfully carried out irradiation grafting with micron-level precision.

[0039] In summary, acrylic acid is successfully grafted onto the surface of UHMWPE through the high-precision directional radiation grafting method provided by the present invention.

[0040] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiments of the present invention can also be modified in various ways. All simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A high-precision directional irradiation grafting method for material surface based on synchrotron radiation, characterized in that: The method comprises: S1: Construct a high-precision directional irradiation grafting system, which includes: a KB mirror, a four-knife slit assembly, an attenuation assembly and a sample control assembly connected in sequence along an axis by a vacuum pipeline; S2: The high-precision directional irradiation grafting system is used in conjunction with a synchrotron radiation scattering beam station 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.

2. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The method focuses the synchrotron radiation light through the KB mirror to converge the irradiation spot to micrometers.

3. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The method controls the light spot shape through the four-blade slit assembly.

4. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The method controls the irradiation dose by adjusting the attenuation component and changing the irradiation time.

5. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The method places and moves the sample through the sample control component so that the beam irradiates a required range.

6. The method for high-precision directional radiation grafting of a material surface 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.

7. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The grafting range of the method is adjustable, and the size of the grafting area is micron-level or submicron-level.

8. The method for high-precision directional radiation grafting of a material surface according to claim 1, characterized in that: The synchrotron radiation scattering beam station system is the Shanghai Light Source synchrotron radiation scattering beam station system.

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