Styrene-methyl methacrylate copolymer foam material and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and particularly discloses a styrene-methyl methacrylate copolymer foam material and a preparation method thereof. The styrene-methyl methacrylate copolymer foaming material is prepared from the following raw materials in parts by weight: 50 to 80 parts of styrene-methyl methacrylate copolymer, 1 to 3 parts of azodicarbonamide and 0.5 to 1 part of polylactic acid microspheres. The compression strength and the tensile strength of the styrene-methyl methacrylate copolymer foaming material obtained by the invention can reach 0.29 Mpa and 0.39 Mpa at most, and the mechanical property of the styrene-methyl methacrylate copolymer foaming material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and more specifically, to a styrene-methyl methacrylate copolymer foaming material and a preparation method thereof. Background Art

[0002] Styrene-methyl methacrylate copolymer foaming material is a foaming material formed by free radical copolymerization of methyl methacrylate and styrene, and then adding a foaming agent to form a polymer. It combines the high transmittance, high heat resistance and good processability of methyl methacrylate with the high refractive index and low moisture absorption of styrene. Styrene-methyl methacrylate copolymer is widely used in various packaging products and can be used for food contact. However, the mechanical properties of styrene-methyl methacrylate copolymer foaming material are relatively low.

[0003] In the related art, therefore, it is very important to develop a styrene-methyl methacrylate copolymer foaming material with high mechanical properties. Summary of the invention

[0004] In order to improve the mechanical properties of a styrene-methyl methacrylate copolymer foam material, the present application provides a styrene-methyl methacrylate copolymer foam material and a preparation method thereof.

[0005] In a first aspect, the present application provides a styrene-methyl methacrylate copolymer foaming material, which adopts the following technical solution: A styrene-methyl methacrylate copolymer foaming material comprises the following raw materials in parts by weight: 50-80 parts of styrene-methyl methacrylate copolymer, 1-3 parts of azodicarbonamide, and 0.5-1 part of polylactic acid microspheres.

[0006] The styrene-methyl methacrylate copolymer foaming material of the present application can be made of 50-80 parts of styrene-methyl methacrylate copolymer, 1-3 parts of azodicarbonamide, and 0.5-1 part of polylactic acid microspheres. Any value within the respective ranges can be selected, and the mechanical properties of the styrene-methyl methacrylate copolymer foaming material can be improved.

[0007] By adopting the above technical solution, adding azodicarbonamide as a foaming agent can ensure that the foaming material generates a foaming material with uniform pore size and uniform pore distribution. Controlling its dosage can avoid the situation where too much foaming agent produces too many pores and the pores are compressed against each other and cause the pores to rupture. Adding polylactic acid microspheres as nucleating agents can regulate the pore structure, induce uniform nucleation, and increase the foaming ratio. At the same time, the uniformly distributed pores reduce stress concentration, thereby improving the mechanical properties. In addition, polylactic acid microspheres are biodegradable and can effectively avoid environmental pollution.

[0008] Preferably, a styrene-methyl methacrylate copolymer foaming material comprises the following raw materials in parts by weight: 55-65 parts of styrene-methyl methacrylate copolymer, 1.5-2.5 parts of azodicarbonamide, and 0.7-0.9 parts of polylactic acid microspheres.

[0009] The styrene-methyl methacrylate copolymer foaming material of the present application can be made of 55-65 parts of styrene-methyl methacrylate copolymer, 1.5-2.5 parts of azodicarbonamide, and 0.7-0.9 parts of polylactic acid microspheres. Any value within the respective ranges can be selected, and the mechanical properties of the styrene-methyl methacrylate copolymer foaming material can be improved.

[0010] Preferably, the raw materials of the styrene-methyl methacrylate copolymer foaming material further include the following raw materials in parts by weight: 0.5-1 part of sodium lauryl sulfate and 1-2 parts of alkylphenol polyoxyethylene ether.

[0011] By adopting the above technical solution, adding sodium dodecyl sulfate can improve the dispersibility of polylactic acid microspheres in the raw material of styrene-methyl methacrylate copolymer foaming material, thereby improving the mechanical properties of styrene-methyl methacrylate copolymer foaming material. Adding alkylphenol polyoxyethylene ether and sodium dodecyl sulfate in combination can further improve the dispersion stability of sodium dodecyl sulfate, thereby improving the mechanical properties of styrene-methyl methacrylate copolymer foaming material.

[0012] Preferably, the weight ratio of sodium lauryl sulfate to alkylphenol polyoxyethylene ether is 1:(2-3).

[0013] By adopting the above technical scheme and adjusting the weight ratio of alkylphenol polyoxyethylene ether and sodium dodecyl sulfate, the dispersion stability of polylactic acid microspheres in the styrene-methyl methacrylate copolymer foaming material raw material can be further improved, thereby further improving the mechanical properties of the styrene-methyl methacrylate copolymer foaming material.

[0014] As a preference, the styrene-methyl methacrylate copolymer is prepared by modification, specifically: S1. Mix polyvinyl alcohol and water, raise the temperature to 90°C, and stir for 20 minutes to obtain a mixed solution A; S2. Cool the mixed solution A to 70°C, add styrene, methyl methacrylate and methacrylic acid and mix well, then add initiator and stir to dissolve and react at a stirring rate of 450r / min. Heat to 90°C and react for 10min, then add basic magnesium carbonate and cross-linking agent and stir to react at a stirring rate of 450r / min. When colloidal particles appear, continue to react for 0.5-1h, and after hardening, ripen for 0.5-1h to stop the reaction, cool, wash, filter and dry to obtain styrene-methyl methacrylate copolymer.

[0015] Among them, the volume amount of polyvinyl alcohol and the mass amount of basic magnesium carbonate are both 0.1%-0.5% of the total volume amount of styrene and methyl methacrylate (total monomer amount); the volume amount of water is 2-3 times the total volume amount of styrene and methyl methacrylate (total monomer amount); the volume ratio of styrene, methyl methacrylate and methacrylic acid is 7:4:1; the volume amount of initiator and cross-linking agent are both 0.1%-0.5% of the total volume amount of styrene and methyl methacrylate (total monomer amount).

[0016] By adopting the above technical scheme, methacrylic acid is added when styrene and methyl methacrylate are added. Methacrylic acid has high reactivity and can promote the copolymerization reaction and improve the reaction rate and conversion rate. In addition, the carboxyl group of methacrylic acid can react chemically with other functional groups to improve the mechanical properties of the styrene-methyl methacrylate copolymer.

[0017] Polyvinyl alcohol is added as a dispersant to improve the dispersibility of raw materials such as methacrylic acid and basic magnesium carbonate and prevent the raw materials from agglomerating. Basic magnesium carbonate is added as a filler to improve the mechanical properties of styrene-methyl methacrylate copolymer, thereby improving the mechanical properties of styrene-methyl methacrylate copolymer foaming materials.

[0018] Preferably, the volume ratio of the basic magnesium carbonate to polyvinyl alcohol is 1:(1.5-2.5).

[0019] By adopting the above technical solution and controlling the volume ratio of basic magnesium carbonate and polyvinyl alcohol, the dispersibility of basic magnesium carbonate in the copolymerization process can be further improved, thereby further improving the mechanical properties of the styrene-methyl methacrylate copolymer foaming material.

[0020] Preferably, the initiator is dibenzoyl peroxide, and the volume usage is 6% of the volume usage of styrene.

[0021] By adopting the above technical solution, dibenzoyl peroxide is added as an initiator. Dibenzoyl peroxide has a high initiation efficiency and can effectively initiate polymerization at a lower concentration. By controlling its dosage, the purity of styrene-methyl methacrylate copolymer can be improved. In addition, dibenzoyl peroxide also has a certain cross-linking effect, which can promote the polymerization reaction between the copolymer molecular chains, thereby improving the mechanical properties of styrene-methyl methacrylate copolymer, thereby further improving the mechanical properties of styrene-methyl methacrylate copolymer foaming material.

[0022] In a second aspect, the present application provides a method for preparing any of the above-mentioned styrene-methyl methacrylate copolymer foaming materials.

[0023] A method for preparing a styrene-methyl methacrylate copolymer foaming material comprises the following steps: drying the styrene-methyl methacrylate copolymer at 50-65° C. for 3-5 hours, adding azodicarbonamide and other raw materials for foaming treatment, and obtaining the styrene-methyl methacrylate copolymer foaming material.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: (1) The present application controls the type and dosage of each raw material in the styrene-methyl methacrylate copolymer foam material so that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam material are 0.21-0.23 MPa and 0.32-0.33 MPa, respectively, thereby improving the mechanical properties of the styrene-methyl methacrylate copolymer foam material.

[0025] (2) The present application modifies the styrene-methyl methacrylate copolymer, adjusts the volume ratio of basic magnesium carbonate and polyvinyl alcohol, determines that the initiator is dibenzoyl peroxide, and controls the amount of the initiator, so that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam material are 0.29 MPa and 0.39 MPa respectively, thereby improving the mechanical properties of the styrene-methyl methacrylate copolymer foam material. DETAILED DESCRIPTION

[0026] The present application is further described in detail below in conjunction with specific embodiments.

[0027] The following raw materials in this application are all commercially available products, and are intended to make the raw materials of this application fully disclosed, and should not be understood as limiting the source of the raw materials. Specifically: azodicarbonamide, model AC foaming agent, effective substance content of 95%; polylactic acid microspheres, particle size of 200μm; alkylphenol polyoxyethylene ether, effective substance content of 99%; sodium dodecyl sulfate, industrial grade specification, model K12; styrene, chemically pure specification; methyl methacrylate, chemically pure specification; methacrylic acid, chemically pure specification; basic magnesium carbonate, analytical pure specification; polyvinyl alcohol, chemically pure specification; crosslinking agent selected divinylbenzene, effective substance content of 99%; initiator, selected azobisisobutyronitrile and dibenzoyl peroxide, among which azobisisobutyronitrile is industrial grade specification, effective substance content of 99.9%, and dibenzoyl peroxide is industrial grade specification, effective substance content of 99%.

[0028] The following is an example of the preparation of modified styrene-methyl methacrylate copolymer Preparation Example 1 The modified styrene-methyl methacrylate copolymer of Preparation Example 1 was prepared by the following steps: S1. Mix 33 mL of polyvinyl alcohol with 27.5 L of water, heat to 90°C, and stir for 20 min to obtain a mixed solution A; S2. Cool the mixed solution A to 70°C, add 7L styrene, 4L methyl methacrylate and 1L methacrylic acid and mix evenly, then add 33mL initiator and stir to dissolve and react at a stirring rate of 450r / min. Heat to 90°C and react for 10min, then add 33g basic magnesium carbonate and 33mL cross-linking agent and stir to react at a stirring rate of 450r / min. When colloidal particles appear, continue to react for 0.5h, and stop the reaction after hardening and ripening for 0.5h. Cool, wash, filter and dry to obtain a modified styrene-methyl methacrylate copolymer.

[0029] Preparation Example 2-5 The preparation methods of the modified styrene-methyl methacrylate copolymers of Preparation Examples 2-5 are the same as those of Preparation Example 1, except that the amounts of polyvinyl alcohol used are 49.5 mL, 66 mL, 82.5 mL and 99 mL, respectively, and the types and amounts of other raw materials are the same as those of Preparation Example 1.

[0030] Example 1 The styrene-methyl methacrylate copolymer foamed material of Example 1 is prepared by the following preparation method: According to the dosage in Table 1, the styrene-methyl methacrylate copolymer was dried at 50-65°C for 3-5h, and azodicarbonamide and polylactic acid microspheres were added for foaming to obtain a styrene-methyl methacrylate copolymer foam material. The styrene-methyl methacrylate copolymer was purchased directly, with a model of 4213, a grade of xm-001, and a particle size of 200μm.

[0031] Example 2-3 The preparation method of the styrene-methyl methacrylate copolymer foam material of Example 2-3 is the same as that of Example 1, except that the dosage of each raw material is different, as shown in Table 1 for details.

[0032] Table 1 Amount of each raw material in the degradable plastic bottle of Example 1-3 (kg)

[0033] Embodiment 4-8 The preparation method of the styrene-methyl methacrylate copolymer foam material of Examples 4-8 is the same as that of Example 2, except that the raw materials of the styrene-methyl methacrylate copolymer foam material also include sodium dodecyl sulfate and alkylphenol polyoxyethylene ether, and the amounts are shown in Table 2. The types and amounts of other raw materials are the same as those of Example 3.

[0034] Table 2 Amount of each raw material in Example 4-8 degradable plastic bottle (kg)

[0035] Examples 9-13 The preparation methods of the styrene-methyl methacrylate copolymer foaming materials of Examples 9-13 are the same as those of Example 6, except that the styrene-methyl methacrylate copolymer in the raw materials of the styrene-methyl methacrylate copolymer foaming materials is the modified styrene-methyl methacrylate copolymer prepared in Preparation Examples 1-5, and the types and amounts of other raw materials are the same as those of Example 6. Azobisisobutyronitrile is used as the initiator.

[0036] Examples 14-16 The preparation method of the styrene-methyl methacrylate copolymer foam material of Examples 14-16 is the same as that of Example 11, except that in the preparation process of the modified styrene-methyl methacrylate copolymer in the raw material of the styrene-methyl methacrylate copolymer foam material, dibenzoyl peroxide is selected as the initiator, and the amounts used are respectively. The types and dosages of other raw materials are the same as those of Example 11.

[0037] Comparative Example 1 The preparation method of the styrene-methyl methacrylate copolymer foam material of Comparative Example 1 is the same as that of Example 1, except that an equal amount of polylactic acid microspheres is replaced by polystyrene microspheres, and the other raw material types and dosages are the same as those of Example 1.

[0038] Performance Testing The performance of the styrene-methyl methacrylate copolymer foamed materials obtained in different Examples 1-16 and Comparative Example 1 was tested respectively. The test results are shown in Table 3.

[0039] Tensile strength: The tensile strength of styrene-methyl methacrylate copolymer foam material was tested according to ASTM D638-2014, see Table 3 for details; Compression strength: The compression strength of styrene-methyl methacrylate copolymer foaming material was tested according to GB / T 8813-2008, see Table 3 for details; Foaming ratio: The compressive strength of styrene-methyl methacrylate copolymer foaming material was tested according to GB / T 6343-2009, see Table 3 for details.

[0040] Table 3 Performance test results of different styrene-methyl methacrylate copolymer foaming materials

[0041] The test results in Table 3 show that the foaming ratio of the styrene-methyl methacrylate copolymer foam material obtained in the present application is 24.0-25.3 times, and the compression strength and tensile strength of the styrene-methyl methacrylate copolymer foam material can reach up to 0.29 MPa and 0.39 MPa, respectively, which improves the mechanical properties of the styrene-methyl methacrylate copolymer foam material.

[0042] Combined with the performance test data of styrene-methyl methacrylate copolymer foam materials in Examples 1-3, it can be seen that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam material in Example 2 are 0.19 MPa and 0.30 MPa, respectively, which are higher than those in Example 1 and Example 3, indicating that the amount of polylactic acid microspheres in the raw material of the styrene-methyl methacrylate copolymer foam material in Example 2 is more appropriate, which improves the mechanical properties of the styrene-methyl methacrylate copolymer foam material.

[0043] Combined with the performance test data of styrene-methyl methacrylate copolymer foam materials of Examples 4-8, it can be seen that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam materials of Examples 5-7 are 0.21-0.23 MPa and 0.32-0.33 MPa, respectively, which are higher than those of Examples 4 and 8, indicating that the weight ratio of sodium dodecyl sulfate to alkylphenol polyoxyethylene ether is 1: (2-3) which is more suitable, thereby improving the mechanical properties of the styrene-methyl methacrylate copolymer foam materials.

[0044] Combined with the performance test data of styrene-methyl methacrylate copolymer foam materials of Examples 9-13, it can be seen that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam materials of Examples 10-12 are 0.26-0.27 MPa and 0.35-0.36 MPa, respectively, which are higher than those of Example 9 and Example 13, indicating that the volume ratio of the mass of basic magnesium carbonate to polyvinyl alcohol is 1: (1.5-2.5) which is more suitable, thereby improving the mechanical properties of the styrene-methyl methacrylate copolymer foam materials.

[0045] Combined with the performance test data of styrene-methyl methacrylate copolymer foam materials of Examples 14-16, it can be seen that the compressive strength and tensile strength of the styrene-methyl methacrylate copolymer foam material of Example 15 are 0.29 MPa and 0.39 MPa, respectively, which are higher than those of Example 14 and Example 16, indicating that the initiator is dibenzoyl peroxide, and the volume dosage is 6% of the volume dosage of styrene, which is more appropriate, thereby improving the mechanical properties of the styrene-methyl methacrylate copolymer foam material.

[0046] In addition, based on the performance test data of the styrene-methyl methacrylate copolymer foam material in Comparative Example 1 and Example 1, it was found that adding polylactic acid microspheres to the raw material of the styrene-methyl methacrylate copolymer foam material can improve the mechanical properties of the styrene-methyl methacrylate copolymer foam material to varying degrees.

[0047] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A styrene-methyl methacrylate copolymer foaming material, characterized in that: The method comprises the following raw materials in parts by weight: 50-80 parts of styrene-methyl methacrylate copolymer, 1-3 parts of azodicarbonamide and 0.5-1 part of polylactic acid microspheres.

2. The styrene-methyl methacrylate copolymer foam material according to claim 1, characterized in that: The method comprises the following raw materials in parts by weight: 55-65 parts of styrene-methyl methacrylate copolymer, 1.5-2.5 parts of azodicarbonamide and 0.7-0.9 parts of polylactic acid microspheres.

3. The styrene-methyl methacrylate copolymer foamed material according to claim 1, characterized in that: The raw materials of the styrene-methyl methacrylate copolymer foaming material also include the following raw materials in parts by weight: 0.5-1 parts of sodium lauryl sulfate and 1-2 parts of alkylphenol polyoxyethylene ether.

4. The styrene-methyl methacrylate copolymer foamed material according to claim 3, characterized in that: The weight ratio of the sodium lauryl sulfate to the alkylphenol polyoxyethylene ether is 1:(2-3).

5. The styrene-methyl methacrylate copolymer foamed material according to claim 1, characterized in that: The styrene-methyl methacrylate copolymer is prepared by modification, specifically: S1. Mix polyvinyl alcohol and water, raise the temperature to 90°C, and stir for 20 minutes to obtain a mixed solution A; S2. Cool the mixed solution A to 70°C, add styrene, methyl methacrylate and methacrylic acid and mix well, then add initiator and stir to dissolve and react at a stirring rate of 450r / min. Heat to 90°C and react for 10min, then add basic magnesium carbonate and cross-linking agent and stir to react at a stirring rate of 450r / min. When colloidal particles appear, continue to react for 0.5-1h, and after hardening, ripen for 0.5-1h to stop the reaction, cool, wash, filter and dry to obtain a modified styrene-methyl methacrylate copolymer.

6. The styrene-methyl methacrylate copolymer foamed material according to claim 5, characterized in that: The mass ratio of the basic magnesium carbonate to the volume ratio of the polyvinyl alcohol is 1:(1.5-2.5).

7. The styrene-methyl methacrylate copolymer foamed material according to claim 5, characterized in that: The initiator is dibenzoyl peroxide, and the volume usage is 6% of the volume usage of styrene.

8. A method for preparing the styrene-methyl methacrylate copolymer foam material according to any one of claims 1 to 7, characterized in that: The method comprises the following operating steps: drying the styrene-methyl methacrylate copolymer at 50-65° C. for 3-5 hours, adding azodicarbonamide and other raw materials for foaming treatment, and obtaining the styrene-methyl methacrylate copolymer foaming material.

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