Photopolymer holographic storage material, holographic optical disc and preparation method thereof

Abstract

The present invention belongs to the technical field of holographic polymer materials, and specifically relates to a photopolymer holographic storage material, a holographic optical disc and a preparation method thereof. The photopolymer holographic storage material is prepared from raw materials in the following mass ratio: MMA: NMP: AIBN: PQ = 100: 5-25: 0.7-1: 1-1.5. The photopolymer holographic storage material is doped with NMP (N-methylpyrrolidone) in PQ / PMMA (phenanthrenequinone / polymethyl methacrylate) to significantly improve the optical properties of the material.

Description

Technical Field

[0001] The invention belongs to the technical field of holographic polymer materials, and in particular relates to a photopolymer holographic storage material, a holographic optical disc and a preparation method thereof. Background Art

[0002] With the advent of the big data era, the rapid development of social activities such as mobile Internet, e-commerce and social media, the amount of data generated by human society has exploded. The generation and dissemination of massive data urgently require high-density, ultra-long-term and low-cost information storage technology. Volume holographic storage technology has the characteristics of high storage density, fast transmission rate and good redundancy, and is considered to be a storage technology with great potential. Holographic storage uses light waves as the main body, and the optical storage density can be improved by adjusting parameters such as amplitude, phase and polarization. In recent years, the use of polarization information to improve the dimensionality of holographic recording has received widespread attention, but these materials have some inherent defects. For example, many polarization-sensitive materials such as photoinduced refractive index change crystals, azo materials and polymer dispersed liquid crystals cannot meet the requirements of holographic recording storage. The main disadvantages of these materials are that their production industry is complex, expensive, the grating is erasable and the material itself is unstable.

[0003] A Chinese invention patent with publication number CN112812210A discloses a thermal polymerization process for a PQ / PMMA photopolymer material and a PQ / PMMA photopolymer material and a holographic optical disc thereof. The invention uses MMA, AIBN and PQ to prepare a photopolymer with stable performance, can record once and read multiple times, is easy to process into a thick holographic material, and has very low photoinduced shrinkage. However, the diffraction efficiency of the PQ-PMMA (phenanthrenequinone-polymethyl methacrylate) photopolymer is not high, which limits its application in the field of high-density holographic storage. Summary of the invention

[0004] In order to overcome the defects of the prior art, the technical problem to be solved by the present invention is to provide a photopolymer holographic storage material, a holographic optical disc and a preparation method thereof, wherein the holographic storage material has higher diffraction efficiency, response efficiency and photosensitivity.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a photopolymer holographic storage material is prepared from the following raw materials in the following mass ratio:

[0006] MMA (methyl methacrylate): NMP (N-methylpyrrolidone): AIBN (azobisisobutyronitrile): PQ (phenanthrenequinone) = 100: 5-25: 0.7-1: 1-1.5.

[0007] Another technical solution adopted by the present invention is: the preparation method of the above-mentioned photopolymer holographic storage material comprises the following steps:

[0008] S1: MMA, NMP, AIBN and PQ are weighed and mixed in a mass ratio of 100:5-25:0.7-1:1-1.5, and then subjected to ultrasonic oscillation to obtain a mixed solution;

[0009] S2: placing the mixed solution in a water bath and heating and stirring to obtain a viscous substance;

[0010] S3: baking the adhesive and then cooling it to obtain a photopolymer holographic storage material.

[0011] Another technical solution adopted by the present invention is: a holographic optical disc, which is prepared by using the above-mentioned photopolymer holographic storage material.

[0012] The beneficial effects of the present invention are as follows: the NMP-doped PQ / PMMA photopolymer holographic storage material of the present invention significantly improves the optical properties of the material by doping NMP (N-methylpyrrolidone) in PQ / PMMA (phenanthrenequinone / polymethyl methacrylate). Compared with the traditional PQ / PMMA material, the material of the present invention has higher diffraction efficiency, refractive index modulation, response efficiency and photosensitivity, and is therefore more suitable for optical holographic storage; the preparation method of the present invention has a simple process and a low raw material cost, making it more competitive in holographic storage materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Shown are diffraction efficiency test diagrams of Examples 1 and 2 of the present invention and Comparative Example 1;

[0014] Figure 2 Shown are test diagrams of refractive index modulation of Examples 1 and 2 of the present invention and Comparative Example 1;

[0015] Figure 3 Shown are photosensitivity test diagrams of Examples 1 and 2 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0016] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0017] The key concept of the present invention is that the optical properties of the material are significantly improved by doping NMP (N-methylpyrrolidone) into PQ / PMMA (phenanthrenequinone / polymethyl methacrylate).

[0018] A photopolymer holographic storage material of the present invention is prepared from the following raw materials in the following mass ratio:

[0019] MMA (methyl methacrylate): NMP (N-methylpyrrolidone): AIBN (azobisisobutyronitrile): PQ (phenanthrenequinone) = 100: 5-25: 0.7-1: 1-1.5.

[0020] From the above description, it can be seen that the beneficial effect of the present invention is that by doping NMP (N-methylpyrrolidone) into PQ / PMMA (phenanthrenequinone / polymethyl methacrylate) for mixing, the optical properties of the material are significantly improved. Compared with traditional PQ / PMMA materials, the material of the present invention has higher diffraction efficiency, refractive index modulation, response efficiency and photosensitivity, and is therefore more suitable for optical holographic storage.

[0021] The NMP ratio will affect the photosensitivity and diffraction efficiency. Too little NMP content will not significantly improve the diffraction efficiency and photosensitivity; excessive NMP will prolong the polymerization time and may even prevent polymerization to the desired viscosity.

[0022] The proportion of AIBN will affect the stirring time in the water bath. Excessive AIBN will lead to severe polymerization and easy to produce implosion.

[0023] The proportion of PQ will affect the diffraction efficiency and photosensitivity. Excessive PQ will cause PQ residue and cannot be dissolved.

[0024] Another technical solution adopted by the present invention is: the preparation method of the above-mentioned photopolymer holographic storage material comprises the following steps:

[0025] S1: MMA, NMP, AIBN and PQ are weighed and mixed in a mass ratio of 100:5-25:0.7-1:1-1.5, and then subjected to ultrasonic oscillation to obtain a mixed solution;

[0026] S2: placing the mixed solution in a water bath and heating and stirring to obtain a viscous substance;

[0027] S3: The viscous material is baked and then cooled to obtain a photopolymer holographic storage material.

[0028] From the above description, it can be seen that the preparation method has a simple process and low raw material cost, making it more competitive in holographic storage materials.

[0029] Furthermore, during the heating and stirring in S2, the water bath temperature is 56-62° C. Preferably, the water bath temperature is 60° C.

[0030] From the above description, it can be seen that if the water bath temperature is too low, the reaction time will be too long or even the thermal polymerization reaction cannot be initiated. If the water bath temperature is too high, the reaction rate will be difficult to control and implosion will easily occur.

[0031] Furthermore, during heating and stirring, the stirring speed is 600 to 1000 r / min. Preferably, the stirring speed is 700 to 900 r / min.

[0032] Furthermore, when heating and stirring, the stirring time is 1 to 2 hours. Preferably, the stirring time is 1.5 to 1.7 hours.

[0033] From the above description, it can be seen that if the stirring time is too short, the viscosity of the monomer will be insufficient, affecting the forming after pouring into the mold. If the stirring time is too long, the viscosity of the monomer will be too high, affecting the operation of pouring into the mold.

[0034] Furthermore, during ultrasonic oscillation, the oscillation time is 10 to 20 minutes. Preferably, the oscillation time is 14 to 17 minutes.

[0035] From the above description, it can be seen that ultrasound will affect the chain length of the polymer. If the ultrasound time is too short, PQ will not be completely dissolved, and if the ultrasound time is too long, the internal monomers will have begun to polymerize.

[0036] Another technical solution adopted by the present invention is: a holographic optical disc, which is prepared by using the above-mentioned photopolymer holographic storage material.

[0037] Embodiment 1 of the present invention is:

[0038] A method for preparing a photopolymer holographic storage material comprises the following steps:

[0039] S1: MMA (methyl methacrylate), NMP (N-methylpyrrolidone), AIBN (azobisisobutyronitrile) and PQ (phenanthrenequinone) were weighed and mixed in a mass ratio of 100:5:1:1, and then ultrasonically vibrated for 15 min to obtain a mixed solution;

[0040] S2: The mixed solution is placed in a water bath and heated and stirred to obtain a viscous substance; during heating and stirring, the water bath temperature is set to 60°C, the stirring speed is 800 r / min, and the stirring time is 75 min.

[0041] S3: pouring the viscous material into a mold and baking it, then cooling and demoulding it to obtain a photopolymer holographic storage material.

[0042] Embodiment 2 of the present invention is:

[0043] The difference between Example 2 and Example 1 is that MMA (methyl methacrylate), NMP (N-methylpyrrolidone), AIBN (azobisisobutyronitrile) and PQ (phenanthrenequinone) are weighed and mixed in a mass ratio of 100:25:1:1.

[0044] Embodiment 3 of the present invention is:

[0045] A method for preparing a photopolymer holographic storage material comprises the following steps:

[0046] S1: MMA (methyl methacrylate), NMP (N-methylpyrrolidone), AIBN (azobisisobutyronitrile) and PQ (phenanthrenequinone) were weighed and mixed in a mass ratio of 100:20:0.7:1.5, and then ultrasonically vibrated for 10 min to obtain a mixed solution;

[0047] S2: Place the mixed solution in a water bath and heat and stir to obtain a viscous substance; during heating and stirring, the water bath temperature is set to 56°C, the stirring speed is 600 r / min, and the stirring time is 1 h.

[0048] S3: pouring the viscous material into a mold and baking it, then cooling and demoulding it to obtain a photopolymer holographic storage material.

[0049] Embodiment 4 of the present invention is:

[0050] A method for preparing a photopolymer holographic storage material comprises the following steps:

[0051] S1: MMA (methyl methacrylate), NMP (N-methylpyrrolidone), AIBN (azobisisobutyronitrile) and PQ (phenanthrenequinone) were weighed and mixed in a mass ratio of 100:25:0.8:1.2, and then ultrasonically vibrated for 20 min to obtain a mixed solution;

[0052] S2: The mixed solution is placed in a water bath and heated and stirred to obtain a viscous substance; during heating and stirring, the water bath temperature is set to 62°C, the stirring speed is 1000 r / min, and the stirring time is 2 h.

[0053] S3: pouring the viscous material into a mold and baking it, then cooling and demoulding it to obtain a photopolymer holographic storage material.

[0054] Comparative Example 1 of the present invention is:

[0055] The difference between Comparative Example 1 and Example 1 is that NMP (N-methylpyrrolidone) is not added, and the mass ratio of MMA:AIBN:PQ is =100:1:1.

[0056] The diffraction efficiency of Examples 1, 2 and Comparative Example 1 was tested, and the test results are shown in Figure 1 ;

[0057] The refractive index modulation of Examples 1, 2 and Comparative Example 1 was tested, and the test results are shown in Figure 2 ;

[0058] The photosensitivity of Examples 1, 2 and Comparative Example 1 was tested, and the test results are shown in Figure 3 ;

[0059] The above test method can be found 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.

[0060] The best diffraction efficiency, best refractive index modulation, best photosensitivity and exposure time corresponding to the best diffraction efficiency of Examples 1 and 2 and Comparative Example 1 are summarized in Table 1.

[0061] Table 1

[0062]

[0063] As shown in Table 1, MMA, AIBN, and PQ are the raw materials for preparing the existing PQ / PMMA photopolymer holographic storage material. When other substances are added, the content of the product-PQ / PMMA polymer will be reduced in theory, thereby reducing the optical properties of the material. However, by comparing the data of Examples 1 and 2 and Comparative Example 1 in Table 1, it can be seen that adding NMP can effectively improve the diffraction efficiency, refractive index modulation, and photosensitivity of PQ / PMMA, shorten the exposure time, and thus improve the response time. Among them, the best diffraction efficiency and refractive index modulation show peaks as the amount of NMP added increases.

[0064] In summary, the optical properties of the material are significantly improved by doping NMP (N-methylpyrrolidone) into PQ / PMMA (phenanthrenequinone / polymethyl methacrylate). Compared with traditional PQ / PMMA materials, the material of the present invention has higher diffraction efficiency, refractive index modulation, response efficiency and photosensitivity, and is therefore more suitable for optical holographic storage.

[0065] The preparation method has simple process and low raw material cost, making it more competitive in holographic storage materials. Among them, if the water bath temperature is too low, the reaction time will be too long or even the thermal polymerization reaction cannot be initiated. If the water bath temperature is too high, the reaction rate will be difficult to control and it will easily produce implosion. If the stirring time is too short, the viscosity of the monomer will be insufficient, which will affect the forming after pouring into the mold. If the stirring time is too long, the viscosity of the monomer will be too high, which will affect the operation of pouring into the mold. If the ultrasonic time is too short, PQ will not be completely dissolved. If the ultrasonic time is too long, the internal monomer will have begun to polymerize, and the ultrasound will affect the chain length of the polymer.

[0066] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a photopolymer holographic storage material, characterized in that: The following steps are involved: S1: MMA, NMP, AIBN and PQ are weighed and mixed in a mass ratio of 100:5~25:0.7~1:1~1.5, and then ultrasonically vibrated for 10~20 minutes to obtain a mixed solution; S2: placing the mixed solution in a water bath and heating and stirring to obtain a viscous substance; S3: baking the adhesive and then cooling it to obtain a photopolymer holographic storage material.

2. The preparation method according to claim 1, characterized in that: When heating and stirring in S2, the water bath temperature is 56~62℃.

3. The preparation method according to claim 1, characterized in that: During the heating and stirring, the stirring speed is 600-1000 r / min.

4. The preparation method according to claim 1, characterized in that: During the heating and stirring, the stirring time is 1 to 2 hours.

5. A holographic optical disc, characterized in that: The holographic optical disc is prepared by using a photopolymer holographic storage material, and the photopolymer holographic storage material is prepared by using the preparation method described in any one of claims 1-4.

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