Holographic storage material and method for producing the same

Abstract

The present application relates to the technical field of holographic storage material, in particular to a new type of holographic storage material and a preparation method thereof.The raw materials of the material include PETA, MMA, PQ and AIBN.The material is modified by introducing dendritic molecular material PETA, and after modification, the modified material not only has the air bubble-free characteristic compared with the traditional PQ / PMMA material, but also has improved photosensitive sensitivity of the material system, can significantly shorten the response time of the material, and the introduction of PETA can improve the grating diffraction efficiency uniformity and holographic performance of the material system.

Description

Technical Field

[0001] This invention relates to the field of holographic storage materials technology, specifically to a holographic storage material and its preparation method. Background Technology

[0002] Photopolymers are a potential storage medium for volume holographic permanent memories, offering high-density storage, low cost, and negligible shrinkage.

[0003] The photophysical and photochemical mechanisms of traditional PQ / PMMA polymer storage media have been studied in detail. For example, the PQ / PMMA photopolymer material disclosed in Chinese invention patent CN112812210A uses MMA (methyl methacrylate), AIBN (azobisisobutyronitrile), and PQ (phenanthrenequinone) to prepare a photopolymer with stable performance, allowing for multiple reads from a single recording, and exhibiting very low photo-shrinkage. However, due to the use of ordinary MMA material as the substrate, it performs poorly in terms of molding and physical properties, resulting in a large number of bubbles in the prepared product and unsatisfactory photosensitivity. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a holographic storage material with few bubbles and good photosensitivity, and a method for preparing the same.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a holographic storage material, the raw materials of which include PETA (pentaerythritol tetraacrylate), MMA, PQ and AIBN.

[0006] Another technical solution adopted in this invention is: a method for preparing holographic storage material, comprising the following steps: adding PETA, MMA, PQ and AIBN, mixing them sequentially, prepolymerizing them, thermally polymerizing them and then cooling them to room temperature to obtain PETA-doped PQ / PMMA photopolymer holographic storage material.

[0007] The beneficial effects of the present invention are as follows: The holographic storage material of the present invention is modified by introducing dendritic molecular material PETA. Compared with the traditional PQ / PMMA material, the modified material not only has bubble-free characteristics, but also the photosensitivity of the material system is improved, which can significantly shorten the response time of the material. The introduction of PETA improves the uniformity of grating diffraction efficiency and holographic performance of the material system to a certain extent. Attached Figure Description

[0008] Figure 1 The image shown is a physical photograph of the sheet material according to Embodiment 2 of the present invention;

[0009] Figure 2 The image shown is a physical photograph of the sheet material of Comparative Example 1 of the present invention;

[0010] Figure 3 The figure shown is a diffraction efficiency test diagram of Embodiment 2 of the present invention;

[0011] Figure 4 The figure shown is a diffraction efficiency test diagram of Comparative Example 1 of the present invention.

[0012] Figure 5 The figure shown is a comparison of the diffraction efficiencies of Embodiment 2 and Comparative Example 1 of the present invention.

[0013] Figure 6 The figure shown is a test diagram of the optimal photosensitivity of Embodiment 2 and Comparative Example 1 of the present invention. Detailed Implementation

[0014] To explain in detail the technical content, objectives, and effects of the present invention, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0015] A holographic storage material made of PETA, MMA, PQ and AIBN.

[0016] As can be seen from the above description, the beneficial effects of the present invention are as follows: The holographic storage material of the present invention incorporates the dendritic monomer pentaerythritol tetraacrylate (PETA) for modification. The dendritic macromolecular structure formed after cross-linking makes the holographic material both aesthetically pleasing and its performance improved to a certain extent. The shape and number of functional groups of the dendritic macromolecular core and the shape and number of functional groups of the branching units determine the shape and size of the dendritic macromolecular. Introducing PETA to modify the polymer to form a dense three-dimensional cross-linked network structure can improve the rigidity and strength of the polymer substrate. PETA has ester groups and unsaturated double bonds similar to MMA, and the two have good compatibility, which is more conducive to increasing the cross-linked network density of the polymer.

[0017] This invention introduces dendritic molecular material PETA, which, compared to traditional PQ / PMMA materials, not only possesses bubble-free properties but also enhances the photosensitivity of the material system, significantly shortening the material's response time. The introduction of PETA also improves the uniformity of grating diffraction efficiency and holographic performance of the material system.

[0018] Furthermore, the mass ratio of PETA, MMA, AIBN, and PQ is 5~20:100:0.7~1:1~1.5.

[0019] As can be seen from the above description, materials with more than 5 wt% PETA have a similar appearance when molded, but have a significant impact on holographic performance.

[0020] Another technical solution adopted in this invention is: a method for preparing holographic storage material, comprising the following steps: adding PETA, MMA, PQ and AIBN, mixing them sequentially, prepolymerizing them, thermally polymerizing them and then cooling them to room temperature to obtain PETA-doped PQ / PMMA photopolymer holographic storage material.

[0021] Furthermore, the specific steps for mixing are: ultrasonic vibration for 3-8 minutes.

[0022] Furthermore, the specific steps for prepolymerization are as follows: stirring at 55~60℃ for 30~40 min.

[0023] As described above, compared to conventional materials, the prepolymerization and ultrasonic oscillation times of this invention are shortened in order to control the gelation time of multifunctional polymers. The polymerization characteristics of the material after adding PETA differ from ordinary materials. If the ultrasonication and stirring times are not controlled, it will instantly gel and become a jelly-like state, which is highly unfavorable for material filling and molding.

[0024] Furthermore, the stirring speed is 580~620 r / min.

[0025] As can be seen from the above description, stirring accelerates the reaction rate, but excessive stirring speed will cause the monomer viscosity to be too high and may also lead to explosive polymerization.

[0026] Furthermore, the specific steps of thermal polymerization are as follows: place at 55~60℃ for 2~20 hours.

[0027] As can be seen from the above description, the key to controlling parameters during polymerization is temperature. The polymerization and molding of polymer materials are closely related to temperature, and proper temperature control should be ensured during experiments.

[0028] Embodiment 1 of the present invention is: a holographic storage material made of PETA, MMA, AIBN and PQ in a mass ratio of 10:100:1:1.

[0029] Embodiment 2 of the present invention is: a method for preparing a holographic storage material, comprising the following steps:

[0030] S1: Weigh PETA, MMA, AIBN and PQ in a mass ratio of 10:100:1:1, mix the weighed solution by ultrasonic vibration at 60℃ for 5 minutes to obtain a solution containing photosensitizer.

[0031] S2: Place the solution containing the photosensitizer into a thermostatic magnetic stirrer and stir in a 58 ℃ water bath for 35 min for prepolymerization. During prepolymerization, the speed should be controlled at 600 r / min to maintain the solution state and prevent it from forming a jelly-like substance, keeping it as fluid as possible.

[0032] S3: The prepolymerized solution is injected into the mold to a height of 2 mm. After baking in an oven at 58 ℃ for 20 h, it is removed and cooled to stop polymerization and demold, thus obtaining a sheet-like holographic storage material.

[0033] Embodiment 3 of the present invention is as follows:

[0034] A method for preparing a holographic storage material includes the following steps:

[0035] S1: Weigh PETA, MMA, AIBN and PQ in a mass ratio of 5:100:0.7:1.2, mix the weighed solution by ultrasonic vibration at 60℃ for 3 min to obtain a solution containing photosensitizer;

[0036] S2: Place the solution containing the photosensitizer into a thermostatic magnetic stirrer and stir in a 55 ℃ water bath for 40 min for prepolymerization. During prepolymerization, the speed should be controlled at 580 r / min to maintain the solution state and prevent it from forming a jelly-like substance, keeping it as fluid as possible.

[0037] S3: The prepolymerized solution is injected into the mold to a height of 2 mm. After baking in an oven at 55 ℃ for 10 h, it is removed and cooled to stop polymerization and demold, thus obtaining a sheet-like holographic storage material.

[0038] Embodiment four of the present invention is as follows:

[0039] A method for preparing a holographic storage material includes the following steps:

[0040] S1: Weigh PETA, MMA, AIBN and PQ in a mass ratio of 20:100:0.9:1.5, mix the weighed solution by ultrasonic vibration at 60℃ for 8 minutes to obtain a solution containing photosensitizer;

[0041] S2: Place the solution containing the photosensitizer into a thermostatic magnetic stirrer and stir in a 60 ℃ water bath for 30 min for prepolymerization. During prepolymerization, the speed should be controlled at 620 r / min to maintain the solution state and prevent it from forming a jelly-like substance, keeping it as fluid as possible.

[0042] S3: The prepolymerized solution is injected into the mold to a height of 2 mm. After baking in an oven at 60 ℃ for 2 hours, it is removed and cooled to stop polymerization and demold, thus obtaining a sheet-like holographic storage material.

[0043] Comparative Example 1 of the present invention is:

[0044] S1: Weigh MMA, AIBN and PQ in a mass ratio of 100:1:1, mix the weighed solution by ultrasonic vibration at 60℃ for 5 min to obtain a solution containing photosensitizer.

[0045] S2: Place the solution containing the photosensitizer into a thermostatic magnetic stirrer and stir in a 58 ℃ water bath for 70 min for prepolymerization. During prepolymerization, the speed should be controlled at 600 r / min to maintain the solution state and prevent it from forming a jelly-like substance, keeping it as fluid as possible.

[0046] S3: The prepolymerized solution is injected into the mold to a height of 2 mm. After baking in an oven at 58 ℃ for 20 h, it is taken out and cooled to stop polymerization and demold, thus obtaining a sheet-like holographic storage material.

[0047] The sheet materials prepared in Example 2 and Comparative Example 1 are respectively Figure 1 and Figure 2 ,Depend on Figure 1 and Figure 2 It is evident that the preparation method described in this application can effectively reduce air bubbles in the material.

[0048] The diffraction efficiencies of Example 2 (PETA-PQ / PMMA) and Comparative Example 1 (PQ / PMMA) were tested, and the results were as follows: Figure 3 and Figure 4 The comparison results of the diffraction efficiencies of the two are shown in [the original text]. Figure 5 .Depend on Figure 5 It can be seen that, compared with PQ / PMMA, PETA-PQ / PMMA has a diffraction efficiency of over 80%, which accelerates the photoresponse speed and improves the uniformity of the material.

[0049] The optimal photosensitivity of Example 2 (PETA-PQ / PMMA) and Comparative Example 1 (PQ / PMMA) was tested, and the test results are shown in [the table below]. Figure 6 ;Depend on Figure 6 It can be seen that the photosensitivity of PETA-PQ / PMMA has been improved.

[0050] The above test methods are described in the reference: Po Hu, Jinhong Li, Junchao Jin, Xiao Lin, & Xiaodi Tan. Highly Sensitive Photopolymer for Holographic Data Storage Containing Methacryl Polyhedral Oligomeric Silsesquioxane [J]. ACS Appl. Mater. Interfaces 2022, 14, 18, 21544–21554.

[0051] In summary, the holographic storage material provided by this invention, by introducing dendritic molecular material PETA, not only possesses the bubble-free characteristics of the material compared to traditional PQ / PMMA materials, but also improves the photosensitivity of the material system, significantly shortening the material's response time. The introduction of PETA also enhances the uniformity of grating diffraction efficiency and the holographic performance of the material system.

[0052] The dendritic monomer pentaerythritol tetraacrylate (PETA) was introduced to modify PQ / PMMA. The resulting dendritic macromolecular structure after crosslinking not only enhances the aesthetics of the holographic material but also improves its performance. The shape and size of the dendritic macromolecular structure are determined by the shape and number of functional groups in the core and the branching units. Introducing PETA to modify the polymer and form a dense three-dimensional crosslinked network structure can improve the rigidity and strength of the polymer substrate. PETA has ester groups and unsaturated double bonds similar to MMA, and the two have good compatibility, which is more conducive to increasing the crosslinked network density of the polymer.

[0053] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent modifications made based on the content of the present invention's specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A holographic storage material, characterized by PETA, MMA, PQ and AIBN, The mass ratio of the PETA, MMA, AIBN and PQ is 5-20:100:0.7-1:1-1.

5.

2. A method of preparing a holographic storage material, characterized in that The method comprises the following steps: PETA, MMA, PQ and AIBN are added, and mixing, prepolymerization, thermal polymerization and cooling to room temperature are sequentially carried out to obtain a PETA-doped PQ / PMMA photopolymer holographic storage material. The mass ratio of the PETA, MMA, AIBN and PQ is 5-20:100:0.7-1:1-1.

5.

3. A method of preparing a holographic storage material according to claim 2, characterized in that The specific step of the mixing is ultrasonic oscillation for 3-8 min.

4. The method for preparing holographic storage material according to claim 2, characterized in that, The specific step of the pre-polymerization is stirring at 55-60 ℃ for 30-40 min.

5. A method of producing a holographic storage material according to claim 4, characterized in that The stirring speed is 580-620 r / min.

6. The method for preparing holographic storage material according to claim 2, characterized in that, The specific step of the thermal polymerization is placing at 55-60 ℃ for 2-20 h.

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