A bionic lumbar spine bone with X-ray imaging function and its preparation method

Abstract

The present invention discloses a bionic lumbar spine bone with X-ray imaging and its preparation method, which relates to the field of bionic technology of medical polymer materials. The technical solution is to stir and mix the raw materials of rigid polyurethane foam and then pour them into a lumbar spine bone mold for foaming to prepare the cancellous bone material of the bionic lumbar spine bone; use the blend modification of styrene-acrylic emulsion and SAN emulsion to prepare the material for bionic cortical bone; and then use the spraying or dipping process to attach the prepared cortical bone to the outer surface of the cancellous bone to form a bionic lumbar spine bone with X-ray imaging. By adding a water-soluble imaging agent in the emulsion synthesis, the present invention realizes the fine distribution of the imaging agent, significantly improves the contrast and clarity of X-ray imaging. Compared with the traditional materials relying on high-concentration inorganic imaging agents, the water-soluble imaging agent not only improves the biocompatibility and environmental protection, but also strengthens the hardness and wear resistance of the material through SAN resin, is applicable to diversified medical and industrial applications, and shows broad market potential.

Description

Technical Field

[0001] The present invention relates to the field of biomimetic technology of medical polymer materials, and particularly to a biomimetic lumbar vertebra bone with X-ray imaging function and a preparation method thereof. Background Art

[0002] In recent years, with the progress of materials science and biomedical engineering, the field of medical bone biomimetic materials has been significantly developed. In particular, polymer materials such as polypropylene, polycarbonate, polylactic acid, and polyurethane have become popular research objects for in-vivo implantation and in-vitro simulation modeling due to their excellent biocompatibility and mechanical properties. These materials can simulate the modulus of real bone, providing new possibilities for 3D printing technology in customized implants and bone repair. However, the imaging ability of these materials under X-ray fluoroscopy has been a long-standing technical problem.

[0003] Although medical bone biomimetic materials have made progress in simulating real bone structures, one of the key problems encountered in their clinical applications is the insufficient X-ray fluoroscopy imaging performance. The density of polymer materials is generally lower than that of real bone. For example, the density of materials such as polypropylene is only about 0.9 g / cm 3 , much lower than the density of the lumbar vertebra bone of young male humans (about 1.228 g / cm 3 ). This significant density difference results in high X-ray transmittance, making it difficult to form effective contrast during imaging, thereby affecting the doctor's ability to identify bone structures and lesion details. In addition, existing imaging technologies mainly rely on adding inorganic imaging agents such as barium and iodine. These imaging agents often need to be used at relatively high concentrations to achieve ideal imaging effects, but at the same time, they also bring problems of biocompatibility and environmental friendliness. Therefore, developing a new imaging material that not only has good X-ray imaging performance but also meets environmental protection requirements has become an urgent technical problem to be solved.

[0004] The present invention aims to solve the problems of poor imaging effect and insufficient hardness of biomimetic bone materials in the prior art. By developing a new type of aqueous coating, not only the imaging effect under X-ray is improved, but also the hardness regulation can be conveniently implemented. In addition, existing imaging materials often ignore environmental impacts and biocompatibility problems while achieving high-contrast imaging, especially when using heavy metals or high-concentration inorganic imaging agents. The aqueous coating proposed in the present invention adopts an environmentally friendly and odorless formula, and achieves excellent imaging effects by introducing a water-soluble imaging agent KI, significantly improving the environmental protection and biocompatibility of the coating. In addition, the colorless and transparent characteristics of the coating and its flexibility to be adjusted by adding colors provide wider applicability for medical and industrial applications. For example, medical biomimetic bones can be white, while industrial non-destructive testing can choose eye-catching yellow or blue, thus meeting more extensive needs at the technical and application levels. Summary of the Invention

[0005] In order to achieve the above-mentioned invention object and address the above-mentioned technical problems,

[0006] the present invention provides a bionic lumbar spine bone with X-ray imaging function, and the bionic lumbar spine bone is prepared by the following preparation steps:

[0007] S1 Preparation of cancellous bone material: The raw materials (A and B materials) of rigid polyurethane foam are stirred and mixed, and then poured into the lumbar spine bone mold to foam and prepare the cancellous bone material of the bionic lumbar spine bone;

[0008] S2 Preparation of cortical bone material: The material of the bionic cortical bone is prepared by blending and modifying styrene-acrylic emulsion and SAN emulsion;

[0009] S3 Preparation of bionic lumbar spine bone: Then, the prepared cortical bone is attached to the outer surface of the cancellous bone by spraying or dipping process to form a bionic lumbar spine bone with X-ray imaging.

[0010] Preferably, the specific preparation steps of the cancellous bone are as follows:

[0011] a1 Premixing: 100 parts of polyether polyol, 1 part of polydimethylsiloxane (PDMS), 30 parts of 1,4-butanediol, 0.2 part of catalyst A33, 1 part of triethanolamine, 10 parts of trimethylolpropane, and 0.8 part of deionized water are stirred evenly in a mixing barrel, and the stirring speed is maintained at 1000 rpm and mixed evenly to obtain material A;

[0012] a2 Adding material B and foaming: While maintaining the stirring of material A, 170 parts of polyphenyl polymethylene polyisocyanate (material B) are slowly added, and the stirring speed needs to be adjusted to 500 rpm and stirred rapidly for 15 seconds;

[0013] a3 Foaming and molding: The mixed liquid material is quickly poured into the lumbar spine bone mold, and the reaction is sealed. The temperature inside the mold is controlled at 25°C, and the curing time is 24 hours.

[0014] Preferably, the specific preparation steps of the cortical bone are as follows:

[0015] b1 Premulsification of styrene-acrylic emulsion: In reactor A, 10 - 20 parts of styrene, 20 - 30 parts of acrylate monomers, 0.5 - 1.5 parts of emulsifier, 0.1 - 3.0 parts of chain transfer agent, and 10 - 40 parts of deionized water are mixed and stirred to form a pre-emulsion;

[0016] b2 Styrene-acrylic emulsion polymerization: Add 10 - 60 parts of deionized water, 0.5 - 3 parts of initiator, 0.5 - 1.0 part of emulsifier, and 1 - 30 parts of developer into reactor B, stir and heat up to 80 °C, and dropwise add the pre-emulsion from step a) under nitrogen protection, carry out emulsion polymerization for 1 - 2 hours. After the reaction is completed, cool down to room temperature to obtain the emulsion;

[0017] b3 Preparation of SAN resin emulsion: Add 30 parts of styrene (ST), 20 parts of acrylonitrile (AN), 1.0 part of emulsifier, 0.5 part of potassium persulfate (KSP), and 100 parts of deionized water into reactor C, and adopt the emulsion polymerization method at a suitable stirring speed to form a styrene-acrylonitrile copolymer (SAN resin) emulsion;

[0018] b4 Modification of mixed SAN resin: Keep the emulsion obtained in step b2 stirring at a constant temperature in reactor B, slowly add 5 - 40 parts of the SAN resin emulsion prepared in step b3 into it, stir evenly, cool the emulsion down to room temperature, add 0.1 - 1.0 part of pigment, and stir evenly to obtain a SAN resin-modified styrene-acrylic emulsion with X-ray imaging function.

[0019] Preferably, the acrylate monomers are selected from two or more of ethyl acrylate, butyl acrylate, and methyl methacrylate.

[0020] Preferably, the emulsifier is selected from one of sodium dodecylbenzenesulfonate, polyoxyethylene fatty alcohol ether, and polyoxyethylene alkylphenol ether, the initiator is ammonium persulfate, and the chain transfer agent is dodecyl mercaptan.

[0021] Preferably, the developer is selected from one or more combinations of potassium iodide (KI), sodium iodide (NaI), and calcium iodide (CaI2).

[0022] Preferably, the stirring speed in step b1 is 1000 - 2000 rpm, the temperature is controlled at 20 - 40 °C, and the time is 10 - 20 minutes; in step b2, the stirring speed is 300 - 500 rpm.

[0023] Preferably, in step b3, the mixing temperature is 40 °C, the stirring speed is 1000 - 2000 rpm, and the time is 10 - 20 minutes.

[0024] Preferably, in step b4, the constant temperature of reactor B is 40 °C, the stirring rate is 300 - 500 rpm, the SAN resin emulsion is slowly added at a rate that is completed in 15 minutes, and the stirring and mixing time after dropping is 30 minutes; after adding the pigment, the stirring rate is 300 - 500 rpm, and the stirring time is 10 minutes.

[0025] Preferably, the preparation steps of step S3 are as follows:

[0026] Attach the cortical bone material to the surface of the cancellous bone material by spraying or impregnation process:

[0027] The spraying process is to adopt a thin spraying process, with the coating thickness of each spraying being 0.3 mm. After drying, the next spraying is carried out, and the number of sprayings is 3 - 5 times;

[0028] The impregnation process is to pour the cortical bone material into a container, immerse all the cancellous bone material in the cortical bone material, slowly lift it out of the liquid surface after 30 seconds, and repeat the impregnation 2 times after the emulsion slowly dries to form a developing coating.

[0029] Beneficial effects brought by the technical solution provided by the present invention:

[0030] Significant improvement in the developing effect: By adding the water-soluble developer KI during the emulsion synthesis process, the present invention realizes the uniform mixing of the developer and the emulsion. This mixing method enables the developer to be distributed in the emulsion in a finer form. Compared with the traditional coarse-grained developer, this fine liquid distribution form significantly enhances the developing contrast and clarity under X-rays. Therefore, a more effective contrast can be formed during the imaging process, significantly improving the doctor's ability to identify bone structures and lesion details, which is crucial for accurate diagnosis and treatment planning.

[0031] Enhancement of environmental protection and biocompatibility: Compared with the traditional developing materials that rely on high-concentration inorganic developers (such as barium, iodine, etc.), the water-soluble developer KI used in the present invention has obvious advantages in terms of safety and biocompatibility. The low-toxic water-soluble developer poses less health risks to the environment and patients, meeting the strict requirements of modern medical materials for environmental protection and human safety.

[0032] Improvement of the mechanical properties of the coating: The addition of SAN resin in the present invention not only improves the developing performance of the emulsion, but also enhances the mechanical properties of the material by increasing the hardness and wear resistance. This makes the modified styrene-acrylic emulsion of the present invention particularly suitable for simulating bone materials of different age groups and different disease populations, such as the bones of children, adults, the elderly, and osteoporosis patients.

[0033] Wide range of applications and flexibility: In addition to the application in medical bionic bones, the colorless and transparent characteristics and adjustable color features of the SAN resin-modified styrene-acrylic emulsion also make it have broad application potential in fields such as industrial non-destructive testing. Different color options can be adjusted according to specific application requirements, providing more customized solutions.

[0034] In summary, through technological innovation, the present invention effectively solves the problem of insufficient performance of medical polymer materials in X-ray imaging. By introducing an environmentally friendly water-soluble imaging agent, the biocompatibility and environmental friendliness of the material are improved. At the same time, the mechanical properties of the material are enhanced, and its application scope is broadened. These beneficial effects give the present invention significant advantages at the technical and application levels and broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 For the X-ray imaging effect of real bone;

[0036] Figure 2 For the X-ray imaging effect of Example 1 of the present invention;

[0037] Figure 3 For the X-ray imaging effect of Example 7 of the present invention;

[0038] Figure 4 For the X-ray imaging effect of Example 8 of the present invention;

[0039] Figure 5 For the X-ray imaging effect of Comparative Example 1 of the present invention;

[0040] Figure 6 For the X-ray imaging effect of Comparative Example 3 of the present invention;

[0041] Figure 7 For the comparative photo of the emulsion appearance of Example 1 and Comparative Example 3 of the present invention;

[0042] Figure 8 For the X-ray imaging effect diagram, where a is Example 1, b is real bone, and c is without the imaging agent. DETAILED DESCRIPTION OF THE INVENTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments. Of course, the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] Example 1

[0045] A bionic lumbar spine bone with X-ray imaging function is prepared by the following preparation steps:

[0046] S1 Preparation of cancellous bone of bionic lumbar spine bone:

[0047] a1 Premixing: Mix 100 parts of polyether polyol with 1 part of polydimethylsiloxane (PDMS), 30 parts of 1,4-butanediol, 0.2 part of catalyst A33, 1 part of triethanolamine, 10 parts of trimethylolpropane, and 0.8 part of deionized water in a mixing bucket, stir evenly at a stirring speed of 1000 rpm, and mix evenly to obtain Material A;

[0048] Add component B to component A and mix: While maintaining the stirring of component A, slowly add 170 parts of component B (polyphenyl polymethylene polyisocyanate), adjust the stirring speed to 500 rpm, and stir for 15 seconds.

[0049] Foaming and molding: Quickly pour the mixed liquid material into the lumbar spine bone mold, and seal the reaction. Control the internal temperature of the mold at 25°C, and the curing time is 24 hours.

[0050] Preparation of cortical bone material:

[0051] Pre-emulsification of styrene-acrylic emulsion: In reactor A, mix 20 parts of styrene, 10 parts of butyl acrylate, 20 parts of methyl methacrylate, 1.0 part of sodium dodecylbenzenesulfonate, 0.3 part of ammonium persulfate, and 30 parts of deionized water. Heat to 40°C at a stirring speed of 500 rpm. After the temperature stabilizes, adjust the stirring speed to 2000 rpm and stir for 20 minutes to form a pre-emulsion.

[0052] Polymerization of styrene-acrylic emulsion: In reactor B, add 20 parts of deionized water, 0.5 part of initiator ammonium persulfate, 0.5 part of emulsifier sodium dodecylbenzenesulfonate, and 15 parts of developer KI. Stir and heat to 80°C at 400 rpm, and dropwise add the pre-emulsion from step b1 under nitrogen protection for emulsion polymerization for 1 hour. After the reaction ends, cool to room temperature to obtain an emulsion.

[0053] Preparation of SAN resin emulsion: First, dissolve 0.5 part of potassium persulfate (KSP) in 50 parts of deionized water to prepare a 1% concentration KSP aqueous solution for standby. Then, in reactor C, add 50 parts of deionized water and 1.0 part of sodium dodecylbenzenesulfonate, heat to 65°C at a stirring speed of 400 rpm. Subsequently, under nitrogen protection, simultaneously dropwise add the KSP aqueous solution and the monomer mixture (pre-mixed 30 parts of styrene and 20 parts of acrylonitrile) at the same dropping speed. After 1 hour of dropping, continue the reaction for 1 hour, and finally keep stirring and cool to room temperature to obtain the SAN resin emulsion.

[0054] Modification of mixed SAN resin: Keep the emulsion obtained in step b2 stirred at a constant temperature in reactor B, slowly add 30 parts of the SAN resin emulsion prepared in step b3, stir evenly, cool the emulsion to room temperature, add 0.5 part of pigment, and stir evenly to obtain a SAN resin-modified styrene-acrylic emulsion with X-ray imaging function.

[0055] Preparation of bionic lumbar spine cortical bone:

[0056] Coat the cortical bone material prepared in step S2 on the surface of the cancellous bone prepared in step S1 by spraying or dipping process:

[0057] The spraying process is as follows: the thin spraying process is adopted, the coating thickness for each spraying is 0.3 mm, the next spraying is carried out after drying, and the number of sprayings is 5 times.

[0058] Example 2

[0059] Prepared according to the same preparation method as in Example 1, except that 5 parts of SAN resin emulsion are added.

[0060] Example 3

[0061] Prepared according to the same preparation method as in Example 1, except that 10 parts of styrene are added in step b1.

[0062] Example 4

[0063] Prepared according to the same preparation method as in Example 1, except that the emulsifier is polyoxyethylene fatty alcohol ether.

[0064] Example 5

[0065] Prepared according to the same preparation method as in Example 1, except that the emulsifier is polyoxyethylene alkylphenol ether.

[0066] Example 6

[0067] Prepared according to the same preparation method as in Example 1, except that 10 parts of ethyl acrylate, 10 parts of butyl acrylate and 10 parts of methyl methacrylate are selected as the acrylate monomers.

[0068] Example 7

[0069] Prepared according to the same preparation method as in Example 1, except that 10 parts of potassium iodide KI and 5 parts of sodium iodide NaI are selected as the developers and used together.

[0070] Example 8

[0071] Prepared according to the same preparation method as in Example 1, except that 10 parts of potassium iodide KI, 3 parts of sodium iodide NaI and 2 parts of calcium iodide CaI 2 are used together as three developers.

[0072] Example 9

[0073] A bionic lumbar spine bone with X-ray imaging function is prepared by the following preparation steps:

[0074] S1 Preparation of cancellous bone of bionic lumbar spine bone:

[0075] a1 Premixing: Mix 10 parts of polyether polyol with 0.5 part of polydimethylsiloxane (PDMS), 10 parts of 1,4-butanediol, 0.1 part of catalyst A33, 0.5 part of triethanolamine, 0.1 part of trimethylolpropane, and 0.1 part of deionized water in a mixing tank and stir evenly. Keep the stirring speed at 1000 rpm until well mixed to obtain Material A.

[0076] a2 Adding and mixing with Material B: While keeping Material A stirred, slowly add 10 parts of Material B (polyphenyl polymethylene polyisocyanate), adjust the stirring speed to 300 rpm, and stir for 15 seconds.

[0077] a3 Foaming and molding: Quickly pour the mixed liquid material into the lumbar spine bone mold and seal for reaction. Control the internal temperature of the mold at 25°C and the curing time at 24 hours.

[0078] S2 Preparation of cortical bone material:

[0079] b1 Pre-emulsification of styrene-acrylic emulsion: In reactor A, mix 10 parts of styrene, 10 parts of ethyl acrylate, 19 parts of butyl acrylate, 0.5 part of emulsifier (polyoxyethylene fatty alcohol ether), 0.1 part of chain transfer agent (dodecyl mercaptan), and 10 parts of deionized water, and stir to form a pre-emulsion. Keep the stirring speed at 1000 rpm for 10 minutes.

[0080] b2 Polymerization of styrene-acrylic emulsion: In reactor B, add 10 parts of deionized water, 0.5 part of initiator (ammonium persulfate), 0.5 part of emulsifier, and 1 part of developer (sodium iodide NaI), stir and heat up to 80°C, and dropwise add the pre-emulsion from step b1 under nitrogen protection for emulsion polymerization for 1 hour. After the reaction, cool down to room temperature to obtain the emulsion.

[0081] b3 Preparation of SAN resin emulsion: In reactor C, add 30 parts of styrene (ST), 20 parts of acrylonitrile (AN), 0.5 part of polyoxyethylene fatty alcohol ether, 0.5 part of potassium persulfate (KSP), and 50 parts of deionized water, and use the emulsion polymerization method to form a styrene-acrylonitrile copolymer (SAN resin) emulsion at a suitable stirring speed. Keep the stirring speed at 1000 rpm for 10 minutes.

[0082] b4 Modification of mixed SAN resin: Keep the emulsion obtained in step b2 stirred at a constant temperature in reactor B, slowly add 5 parts of the SAN resin emulsion prepared in step b3, stir evenly, cool the emulsion down to room temperature, add 0.1 part of pigment, and stir evenly to obtain a SAN resin-modified styrene-acrylic emulsion with X-ray imaging function.

[0083] S3 Preparation of bionic lumbar spine cortical bone:

[0084] The dipping process is as follows: Pour the cortical bone material into a container, immerse all the cancellous bone material in the cortical bone material, slowly lift it out of the liquid surface after 30 seconds, and repeat the dipping 2 times after the emulsion has slowly dried to form a developer coating.

[0085] Example 10

[0086] A bionic lumbar spine bone with X-ray imaging function is prepared by the following preparation steps:

[0087] S1 Preparation of cancellous bone of bionic lumbar spine bone:

[0088] a1 Premixing: Stir 20 parts of polyether polyol, 1.5 parts of polydimethylsiloxane (PDMS), 40 parts of 1,4-butanediol, 0.5 part of catalyst A33, 1.5 parts of triethanolamine, 10 parts of trimethylolpropane, and 3.0 parts of deionized water evenly in a mixing bucket. Keep the stirring speed at 2000 rpm for 20 minutes as Material A.

[0089] a2 Add Material B and mix: While keeping Material A stirred, slowly add 170 parts of polyphenyl polymethylene polyisocyanate (Material B), and adjust the stirring speed to 500 rpm and keep stirring for 15 seconds.

[0090] a3 Foaming and molding: Quickly pour the mixed liquid material into the lumbar spine bone mold and seal the reaction. Control the temperature inside the mold at 55 °C and the curing time at 30 minutes.

[0091] S2 Preparation of cortical bone material:

[0092] b1 Pre-emulsification of styrene-acrylic emulsion: Mix 20 parts of styrene, 10 parts of ethyl acrylate, 20 parts of butyl acrylate, 1.5 parts of polyoxyethylene alkylphenol ether, 3.0 parts of chain transfer agent, and 40 parts of deionized water in Reactor A and stir to form a pre-emulsion. The stirring speed is 2000 rpm and the stirring time is 20 minutes.

[0093] b2 Polymerization of styrene-acrylic emulsion: Add 60 parts of deionized water, 3 parts of ammonium persulfate, 1.0 part of polyoxyethylene alkylphenol ether, and 30 parts of calcium iodide CaI 2 , stir and heat up to 80 °C, and dropwise add the pre-emulsion from step b1 under nitrogen protection for emulsion polymerization for 2 hours. After the reaction is completed, cool down to room temperature to obtain an emulsion.

[0094] Preparation of b3 SAN resin emulsion: Add 30 parts of styrene (ST), 20 parts of acrylonitrile (AN), 1.0 part of polyoxyethylene alkylphenol ether, 0.5 part of potassium persulfate (KSP), and 100 parts of deionized water into reactor C. Using the emulsion polymerization method, form a styrene-acrylonitrile copolymer (SAN resin) emulsion at a suitable stirring speed. The stirring speed is 2000 rpm, and the stirring time is 20 minutes.

[0095] Modification of b4 mixed SAN resin: Stir the emulsion obtained in step b2 at a constant temperature in reactor B. Slowly add 40 parts of the SAN resin emulsion prepared in step b3 into it and stir evenly. Cool the emulsion to room temperature, add 1.0 part of pigment, and stir evenly to obtain a modified styrene-acrylic emulsion with X-ray imaging function.

[0096] Preparation of S3 cortical bone of bionic lumbar spine

[0097] Impregnation process: Immerse all the cancellous bone materials in the cortical bone materials. Slowly lift them out of the liquid surface after 30 seconds. Repeat the impregnation 2 times after the emulsion dries slowly to form an imaging coating.

[0098] Comparative Example 1

[0099] Prepared according to the same preparation method as in Example 1, except that 5 parts of traditional imaging agent barium sulfate is used as the imaging agent.

[0100] Comparative Example 2

[0101] Prepared according to the same preparation method as in Example 1, except that no SAN resin emulsion is added for modification. The implementation steps are as follows:

[0102] a) Pre-emulsification: Mix 20 parts of styrene, 10 parts of butyl acrylate, 20 parts of methyl methacrylate, 1.0 part of sodium dodecylbenzenesulfonate, 0.3 part of ammonium persulfate, and 30 parts of deionized water in reactor A. Heat to 40 °C at a stirring speed of 500 rpm. After the temperature is stable, adjust the stirring speed to 2000 rpm and stir for 20 minutes to form a pre-emulsion.

[0103] b) Emulsion polymerization: Add 20 parts of deionized water, 0.5 part of initiator ammonium persulfate, 0.5 part of emulsifier sodium dodecylbenzenesulfonate, and 15 parts of imaging agent KI into reactor B. Heat to 80 °C at a stirring speed of 400 rpm, and dropwise add the pre-emulsion from step a) under nitrogen protection for emulsion polymerization for 1 hour. After the reaction ends, adjust the stirring speed to 300 rpm, cool to 40 °C, then add 0.5 part of white pigment (rutile titanium dioxide), and adjust the stirring speed to 500 rpm. After stirring for 10 minutes, obtain a white styrene-acrylic emulsion with X-ray imaging function.

[0104] c) Construction process: The thin spraying process is adopted, with the coating thickness of each spraying being 0.3 mm. The next spraying is carried out after drying, and the number of sprayings is 5 times.

[0105] Comparative Example 3

[0106] Prepared according to the same preparation method as in Example 1, except that the process of adding the developer is different. The implementation steps are as follows:

[0107] a) Pre-emulsification: In reactor A, 20 parts of styrene, 10 parts of butyl acrylate, 20 parts of methyl methacrylate, 1.0 part of sodium dodecylbenzenesulfonate, 0.3 part of ammonium persulfate and 30 parts of deionized water are mixed. The temperature is raised to 40 °C at a stirring speed of 500 rpm. After the temperature is stable, the stirring speed is adjusted to 2000 rpm, and the stirring time is 20 minutes to form a pre-emulsion.

[0108] b) Emulsion polymerization: In reactor B, 20 parts of deionized water, 0.5 part of initiator ammonium persulfate, 0.5 part of emulsifier sodium dodecylbenzenesulfonate are added. The temperature is raised to 80 °C at a stirring speed of 400 rpm, and the pre-emulsion from step a) is added dropwise under nitrogen protection. Emulsion polymerization is carried out for 1 hour. After the reaction is completed, the stirring speed is adjusted to 300 rpm, and the temperature is lowered to room temperature to obtain an emulsion;

[0109] c) Preparation of SAN resin emulsion: First, 0.5 part of potassium persulfate (KSP) is dissolved in 50 parts of deionized water to prepare a 1% concentration KSP aqueous solution for standby. Then, in reactor C, 50 parts of deionized water and 1.0 part of sodium dodecylbenzenesulfonate are added. The temperature is raised to 65 °C at a stirring speed of 400 rpm. Subsequently, under nitrogen protection, the KSP aqueous solution and the monomer mixture (30 parts of styrene and 20 parts of acrylonitrile premixed) are added dropwise at the same dropping rate. After 1 hour of dropping is completed, the reaction continues for 1 hour. Finally, the stirring is maintained and the temperature is lowered to room temperature to obtain the SAN resin emulsion;

[0110] d) Modification of mixed SAN resin: The emulsion obtained in step b) is heated to 40 °C in reactor B at a stirring rate of 300 rpm. 30 parts of the SAN resin emulsion prepared in step c) are slowly added to reactor B within 15 minutes. After the dropping is completed, stirring and mixing continue for 30 minutes; then 15 parts of developer KI and 0.5 part of white pigment (rutile titanium dioxide) are added, and the stirring speed is adjusted to 500 rpm. After stirring for 10 minutes, a white SAN resin-modified styrene-acrylic emulsion with X-ray imaging function is obtained.

[0111] e) Construction process: The thin spraying process is adopted, with the coating thickness of each spraying being 0.3 mm. The next spraying is carried out after drying, and the number of sprayings is 5 times.

[0112] Performance testing

[0113] 1. Hardness test:

[0114] The test of coating hardness is carried out according to the pencil method for measuring paint film hardness standard GB / T 6739-2022. After grinding, cleaning and drying the surface of a tinplate with a size of 120 mm × 50 mm × 0.3 mm, the prepared emulsion is evenly applied to the surface of the test plate with a paint brush. After drying at room temperature for 7 days, the test is carried out on a pencil scratch hardness tester. The scratch test is carried out three times with a pencil of the same hardness, and the damage of the sample is observed. The hardness of the hardest pencil that does not cause scratches on the coating is used to represent the pencil hardness of the coating.

[0115] 2. X-ray scanning test:

[0116] The Cios Select mobile C-arm X-ray machine of Shanghai Siemens Medical Devices Co., Ltd. was used to test the imaging effect of the prepared bionic lumbar vertebrae under the conditions of 60kV voltage, 10mA current and exposure for 0.2s.

[0117] Table 1 Hardness test data

[0118] Sample Pencil hardness Example 1 7H Example 2 4H Example 3 6H Example 6 5H Comparative Example 2 2H

[0119] The hardness in Example 1 is the highest, indicating that the hardness of the coating can be significantly enhanced by using the optimal ratio of SAN resin, which is very critical for the construction of cortical bone in the bionic human bone structure.

[0120] By comparing Example 2 with Example 1, it can be seen that the amount of SAN resin used has a direct effect on hardness. This is because both styrene and acrylonitrile monomers are "hard monomers". Therefore, the hardness of the bionic cortical bone can be regulated by adjusting the amount of SAN resin emulsion to match the modulus of bones in different age groups.

[0121] The data of Examples 3 and 6 further verify the effect of monomer composition on hardness and support the strategy of optimizing hardness by changing the monomer ratio.

[0122] All examples showed higher hardness compared to Comparative Example 2, which emphasizes the innovative use of SAN resin in improving the hardness and overall performance of the coating.

[0123] from Figures 1-6 It can be seen that compared with the real lumbar vertebrae X-ray image ( Figure 1 ) compared with the traditional developer BaSO 4 The developing effect (Comparative Example 1, Figure 5 ) is poor, which is due to BaSO 4 Insoluble in aqueous emulsion, resulting in BaSO 4Dispersed in the emulsion in the form of particles, its development effect depends on the particle size. BaSO 4 has a density of 4.50 g·cm -3 , and it is extremely easy to settle and delaminate in the emulsion, resulting in poor development effect.

[0124] Comparative Example 3 ( Figure 6 ) is to add a developer in reaction step d). At this time, the emulsion system has been stabilized. Adding salts such as potassium iodide and sodium iodide easily causes demulsification of the emulsion system. As shown in Figure 7 , the brushing process also brings about uneven film formation of the coating due to emulsion demulsification. Due to the gravitational effect, the developer is easily deposited at the bottom of the bone, resulting in uneven development.

[0125] Figure 7 The display shows that the white emulsion sample of Comparative Example 3 has a delamination phenomenon. The upper layer is a layer of clear water, and the lower layer is the precipitated emulsion. This delamination is a demulsification phenomenon caused by the instability of the emulsion preparation process. Demulsification refers to the aggregation and coalescence of the dispersed phase (oil droplets wrapped by emulsifiers) in the emulsion due to insufficient stability, and then the separation of the aqueous phase, resulting in the deposition of the emulsion components and the formation of delamination. This phenomenon indicates that the emulsification effect and long-term stability of the emulsion are not good.

[0126] Figure 8 Comparing the development of the bionic bone (a), real vertebra (b), and bionic bone without a sprayed development coating (c) of Spraying Example 1, it can be seen that (c) has almost no development effect, while the development effect of (a) is ideal and close to that of the real vertebra (b).

[0127] Based on the comprehensive hardness data and X-ray development effect, it can be concluded that this emulsion has hardness controllability and good X-ray development effect, and can be used as a bionic coating for bones. In addition, it can also be used as an industrial X-ray flaw detection coating.

[0128] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bionic lumbar vertebra skeleton with X-ray imaging function, characterized in that: The bionic lumbar vertebra skeleton is prepared by the following preparation steps: S1 Preparation of cancellous bone material: Mix the A and B materials of the hard polyurethane foam raw materials and pour them into a lumbar vertebrae bone mold for foaming to prepare a cancellous bone material of a bionic lumbar vertebrae bone. The specific preparation steps of the cancellous bone are as follows: a1 Premixing: Mix 100 parts of polyether polyol, 1 part of polydimethylsiloxane, 30 parts of 1,4-butanediol, 0.2 parts of catalyst A33, 1 part of triethanolamine, 10 parts of trimethylolpropane and 0.8 parts of deionized water in a mixing barrel and stir evenly at a stirring speed of 1000 rpm to obtain material A. a2 Add material B and foam: While stirring material A, slowly add 170 parts of material B polyphenyl polymethylene polyisocyanate, the stirring speed needs to be adjusted to 500 rpm, and stir quickly for 15 seconds; a3 Foaming molding: Pour the mixed liquid material into the lumbar vertebrae bone mold quickly and seal the reaction. The temperature inside the mold is controlled at 25°C and the curing time is 24 hours. Preparation of S2 cortical bone material: The bionic cortical bone material is prepared by blending and modifying styrene acrylic emulsion and SAN emulsion. The specific preparation steps of the cortical bone are as follows: b1 Pre-emulsification of styrene-acrylic emulsion: 10-20 parts of styrene, 20-30 parts of acrylic monomer, 0.5-1.5 parts of emulsifier, 0.1-3.0 parts of chain transfer agent and 10-40 parts of deionized water are mixed in reactor A and stirred to form a pre-emulsion; b2 Styrene-acrylic emulsion polymerization: add 10-60 parts of deionized water, 0.5-3 parts of initiator, 0.5-1.0 parts of emulsifier and 1-30 parts of developer into reactor B, stir and heat to 80°C, and dropwise add the pre-emulsion of step b1 under nitrogen protection, and carry out emulsion polymerization for 1-2 hours. After the reaction is completed, cool to room temperature to obtain an emulsion; b3 Preparation of SAN resin emulsion: 30 parts of styrene, 20 parts of acrylonitrile, 1.0 parts of emulsifier, 0.5 parts of potassium persulfate and 100 parts of deionized water were added to reactor C to form styrene-acrylonitrile copolymer (SAN resin) emulsion by emulsion polymerization at a suitable stirring speed. b4 Mixing SAN resin modification: The emulsion obtained in step b2 is stirred at a constant temperature in reactor B, 5-40 parts of the SAN resin emulsion prepared in step b3 are slowly added thereto, stirred evenly, the emulsion is cooled to room temperature, 0.1-1.0 parts of pigment are added, and stirred evenly to obtain a SAN resin modified styrene acrylic emulsion with X-ray development function, The developer is selected from one or more combinations of potassium iodide KI, sodium iodide NaI, and calcium iodide CaI2. Preparation of S3 bionic lumbar vertebrae: The prepared cortical bone is then attached to the outer surface of the cancellous bone using a spraying or dipping process to form a bionic lumbar vertebrae with X-ray imaging. The acrylic acid ester monomer is selected from two or more of ethyl acrylate, butyl acrylate and methyl methacrylate.

2. The bionic lumbar vertebra skeleton according to claim 1, characterized in that: The emulsifier is selected from one of sodium dodecylbenzene sulfonate, polyoxyethylene fatty alcohol ether and polyoxyethylene alkylphenol ether, the initiator is ammonium persulfate, and the chain transfer agent is dodecyl mercaptan.

3. The bionic lumbar vertebra skeleton according to claim 1, characterized in that: In the step b1, the stirring speed is 1000-2000 rpm, the temperature is controlled at 20-40° C., and the time is 10-20 minutes; in the step b2, the stirring speed is 300-500 rpm.

4. The bionic lumbar vertebra skeleton according to claim 1, characterized in that: In step b3, the mixing temperature is 40° C., the stirring speed is 1000-2000 rpm, and the time is 10-20 minutes.

5. The bionic lumbar vertebra skeleton according to claim 1, characterized in that: In the step b4, the constant temperature of the reactor B is 40° C., the stirring rate is 300-500 rpm, the SAN resin emulsion is slowly added dropwise for 15 minutes, and the stirring and mixing time after the addition is completed is 30 minutes; after the pigment is added, the stirring rate is 300-500 rpm, and the stirring time is 10 minutes.

6. The bionic lumbar vertebra skeleton according to claim 1, characterized in that: The preparation steps of step S3 are: The cortical bone material is attached to the surface of the cancellous bone material by spraying or dipping: The spraying process is to use a thin spraying process, with a coating thickness of 0.3 mm each time, and the next spraying is carried out after drying, and the number of spraying times is 3-5 times; The dipping process is as follows: pour the cortical bone material into a container, immerse all the cancellous bone material in the cortical bone material, slowly pull out of the liquid surface after 30 seconds, and repeat the dipping twice after the emulsion is completely dry to form a developing coating.

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