High-toughness, high-strength and high-temperature-resistant PMI foam

Abstract

The invention discloses high-toughness, high-strength and high-temperature-resistant PMI foam, and relates to the field of high polymer materials. The PMI foam is prepared by mixing methacrylic acid, methacrylonitrile, an initiator, a modifier, a foaming agent, a cross-linking agent and a nucleating agent according to a specific proportion, and carrying out mechanical stirring, water bath polymerization and heating foaming. By controlling the temperature and time of the polymerization reaction and completing the polymerization reaction under specific foaming conditions, the obtained PMI foam material shows excellent toughness, strength and high temperature resistance, and is suitable for the field of light high-strength structural materials.

Description

Technical Field

[0001] The invention relates to the field of polymer materials, in particular to a high-toughness, high-strength and high-temperature-resistant PMI foam. Background Art

[0002] With the advancement of science and technology and the continuous improvement of industrial demand, the application demand of high-performance foam materials in aerospace, automobile, electronics and construction is growing. However, traditional foam materials have great limitations in strength and toughness, and are usually difficult to withstand complex and variable external forces, especially in high temperature or high impact environments. They are more prone to damage. These limitations of traditional foam materials restrict their application in many harsh conditions.

[0003] In the field of aerospace, the structural components of aircraft need to withstand huge dynamic loads during high-speed flight, takeoff and landing, and encountering air turbulence. PMI (polymethacrylimide) foam has gradually been used in sandwich structures, thermal insulation layers and sound insulation materials of aircraft due to its excellent light weight and thermal insulation properties. However, traditional PMI foam materials still have deficiencies in toughness and strength, and it is difficult to cope with various severe loads during aircraft operation. For example, under high-speed flight and strong airflow, the structural components of aircraft need to withstand composite forces such as impact, tension and compression, and PMI foam, as one of the supporting structural materials, must provide reliable support and cushioning to ensure the stability of the aircraft structure and flight safety. Therefore, improving the toughness and strength of PMI foam and enhancing its ability to withstand complex external forces have become key directions for improving the performance of aerospace materials.

[0004] In addition, in the automotive industry, material stability in high temperature environments is crucial. Traditional foam materials are prone to softening, decomposition, or even burning in high temperature environments, resulting in performance degradation or material failure, and cannot meet the application requirements of high-temperature areas such as the engine compartment. The temperature in the engine compartment of a car can be as high as 100-150°C, requiring the material to maintain excellent thermal insulation, sound insulation, and structural support properties at high temperatures. Traditional PMI foam materials are prone to degradation at high temperatures and cannot adapt to the demanding requirements of high temperature environments. In contrast, high-toughness, high-strength, and high-temperature resistant PMI foam materials exhibit better thermal stability under high temperature conditions, are not easy to soften or decompose, and can remain stable in high-temperature areas such as the engine compartment, improving the overall reliability and durability of the vehicle.

[0005] In summary, developing a PMI foam material with high toughness, high strength and high temperature resistance has become an important direction to improve the application performance of this material in the aerospace and automotive fields. Summary of the invention

[0006] In order to solve the technical problems in the above-mentioned background technology, the present invention enhances the strength and toughness of the PMI foam material through a modifier, specific cross-linking and foaming conditions, so that it can still maintain the integrity of the structure when facing variable external forces and high temperature environments, solves the shortcomings of the prior art, and provides a more reliable and safe material choice for applications in the above-mentioned fields.

[0007] The technical solution adopted by the present invention to solve its technical problem is: A high-toughness, high-strength, and high-temperature-resistant PMI foam, characterized in that it comprises the following steps: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle according to the mass proportions, wherein the mass ratio of each component is: Methacrylic acid: 40-70 parts; Methacrylonitrile: 30-50 parts; Initiator: 1-5 parts; High temperature resistant modifier: 0.1-0.5 parts; Foaming agent: 1-10 parts; Cross-linking agent: 1-5 parts; Nucleating agent: 1-5 parts; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material.

[0008] Furthermore, the water bath polymerization reaction temperature is 25-120° C. and the time is 100-350 minutes.

[0009] Furthermore, the heating and foaming temperature is 140-250° C., and the foaming time is 0.5-10 hours.

[0010] Furthermore, when the material mixture is injected into the mold, the filling rate inside the mold is 40%-80%.

[0011] Furthermore, the initiator is selected from at least one of benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, and azobisisobutyronitrile.

[0012] Furthermore, the foaming agent is selected from at least one of nitrogen, carbon dioxide, n-pentane and isopentane.

[0013] Furthermore, the crosslinking agent is selected from at least one of divinylbenzene, trimethylolpropane triacrylate, bisphenol A diglycidyl ether, and isophthalic acid dienyl ester.

[0014] Furthermore, the nucleating agent is selected from at least one of silicon dioxide nanoparticles, aluminum oxide nanoparticles, boron nitride nanoparticles, and titanium dioxide nanoparticles.

[0015] Furthermore, the high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is: Slowly add 13-26 parts of 4-vinylbenzocyclobutene (CAS: 99717-87-0), 0.05-0.7 parts of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium (CAS: 12289-94-0), 25-50 parts of 4,4′-dimercaptostilbene (CAS: 614756-39-7), and 2-6 parts of sodium ethoxide into 200-300 parts of toluene, mix and stir at 65-75° C. for 40-100 minutes, and remove toluene by distillation to obtain a high temperature resistant modifier.

[0016] Reaction mechanism of high temperature resistant modifier: The 4-vinylbenzocyclobutene undergoes a thiol-vinyl addition reaction with a thiol group of 4,4'-dimercaptostilbene; the bis-(2-methylallyl)cyclooct-1,5-dieneruthenium undergoes a thiol-vinyl addition reaction with a thiol group of 4,4'-dimercaptostilbene; and the stilbene containing benzocyclobutene and cyclooct-1,5-dieneruthenium is obtained, which can participate in the polymerization reaction of methacrylic acid and methacrylonitrile, thereby improving the high temperature resistance of PMI foam.

[0017] Beneficial effects of high temperature resistant modifier: As specific functional groups, the introduction of benzocyclobutene and cyclooct-1,5-diene ruthenium into PMI foam may change the molecular structure of the material in the following ways, thereby enhancing the thermal stability of the material: the introduction of benzocyclobutene and cyclooct-1,5-diene ruthenium may increase the π-π interaction between molecules. These interaction forces help stabilize the molecular structure and reduce the movement and rearrangement of molecular chains at high temperatures, thereby improving the thermal stability of the material.

[0018] The introduction of benzocyclobutene and cyclooctane-1,5-diene ruthenium increases the glass transition temperature of PMI foam, allowing the material to maintain a solid structure at higher temperatures and not easily deform or flow. Benzocyclobutene and cyclooctane-1,5-diene ruthenium may reduce the thermal decomposition rate of the material at high temperatures by increasing the rigidity and stability of the molecular chain. This means that PMI foam can maintain its structure and performance for a longer time in a high temperature environment.

[0019] Technical effects: 1. High temperature stability: The PMI foam material prepared by the present invention still has good mechanical strength and toughness under high temperature conditions and is suitable for long-term high temperature environment.

[0020] 2. Excellent strength and toughness: The material exhibits high tensile strength and toughness, can withstand complex and changeable external forces, and is suitable for application scenarios with high strength requirements such as aerospace.

[0021] 3. Low density: Foam materials have low density, which helps to reduce the weight of the structure and is suitable for lightweight and high-strength structural needs.

[0022] 4. Good formability: The material has good formability and is easy to process into complex shapes to meet a variety of structural design requirements. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0024] Detection method: Apparent density shall comply with GB / T 6343-2009 Determination of apparent density of foam plastics and rubber; The tensile properties are measured according to "ASTM-D638-2010 Plastic Tensile"; The compression performance is in accordance with GB / T 8813-2008 Determination of compression performance of rigid foam plastics; The heat deformation temperature is in accordance with "DIN 53424 High temperature dimensional stability under bending and compressive stress".

[0025] Example 1 A high-toughness, high-strength, and high-temperature-resistant PMI foam, characterized in that it comprises the following steps: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle, wherein the mass ratio of each component is: Methacrylic acid: 40 g; Methacrylonitrile: 30g; Initiator: 1g; High temperature resistant modifier: 0.1g; Foaming agent: 1g; Cross-linking agent: 1g; Nucleating agent: 1g; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material.

[0026] The water bath polymerization reaction temperature is 25° C. and the reaction time is 350 minutes.

[0027] The heating and foaming temperature is 140° C., and the foaming time is 10 hours.

[0028] When the material mixture is injected into the mold, the filling rate inside the mold is 40%.

[0029] The initiator is selected from benzoyl peroxide.

[0030] The blowing agent is selected from nitrogen.

[0031] The crosslinking agent is selected from divinylbenzene.

[0032] The nucleating agent is selected from silica nanoparticles.

[0033] The high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is as follows: Slowly add 13 g of 4-vinylbenzocyclobutene (CAS: 99717-87-0), 0.05 g of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium (CAS: 12289-94-0), 25 g of 4,4′-dimercaptostilbene (CAS: 614756-39-7), and 2 g of sodium ethoxide into 200 g of toluene, mix and stir at 65° C. for 100 min, and distill to remove toluene to obtain a high temperature resistant modifier.

[0034] Example 2 A high-toughness, high-strength, and high-temperature-resistant PMI foam, characterized in that it comprises the following steps: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle, wherein the mass ratio of each component is: Methacrylic acid: 50 g; Methacrylonitrile: 45g; Initiator: 2.5g; High temperature resistant modifier: 0.2g; Foaming agent: 3.5g; Cross-linking agent: 2.5 g; Nucleating agent: 2g; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material.

[0035] The water bath polymerization reaction temperature is 60° C. and the reaction time is 250 minutes.

[0036] The heating and foaming temperature is 200° C., and the foaming time is 7.5 hours.

[0037] When the material mixture is injected into the mold, the filling rate inside the mold is 60%.

[0038] The initiator is selected from dicumyl peroxide.

[0039] The blowing agent is selected from carbon dioxide.

[0040] The crosslinking agent is selected from trimethylolpropane triacrylate.

[0041] The nucleating agent is selected from alumina nanoparticles.

[0042] The high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is as follows: Slowly add 17 g of 4-vinylbenzocyclobutene (CAS: 99717-87-0), 0.25 g of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium (CAS: 12289-94-0), 35 g of 4,4′-dimercaptostilbene (CAS: 614756-39-7), and 4 g of sodium ethoxide into 250 g of toluene, mix and stir at 70°C for 60 minutes, and distill to remove toluene to obtain a high temperature resistant modifier.

[0043] Example 3 A high-toughness, high-strength, and high-temperature-resistant PMI foam, characterized in that it comprises the following steps: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle, wherein the mass ratio of each component is: Methacrylic acid: 60 g; Methacrylonitrile: 45g; Initiator: 4g; High temperature resistant modifier: 0.35g; Foaming agent: 8g; Cross-linking agent: 4g; Nucleating agent: 4g; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material.

[0044] The water bath polymerization reaction temperature is 90° C. and the reaction time is 160 minutes.

[0045] The heating foaming temperature is 235° C., and the foaming time is 3 hours.

[0046] When the material mixture is injected into the mold, the filling rate inside the mold is 60%.

[0047] The initiator is selected from di-tert-butyl peroxide.

[0048] The blowing agent is selected from isopentane.

[0049] The crosslinking agent is selected from bisphenol A diglycidyl ether.

[0050] The nucleating agent is selected from boron nitride nanoparticles.

[0051] The high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is as follows: Slowly add 22g of 4-vinylbenzocyclobutene (CAS: 99717-87-0), 0.5g of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium (CAS: 12289-94-0), 45g of 4,4′-dimercaptostilbene (CAS: 614756-39-7), and 5g of sodium ethoxide into 250g of toluene, mix and stir at 70°C for 80min, and distill to remove toluene to obtain a high temperature resistant modifier.

[0052] Example 4 A high-toughness, high-strength, and high-temperature-resistant PMI foam, characterized in that it comprises the following steps: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle, wherein the mass ratio of each component is: Methacrylic acid: 70 g; Methacrylonitrile: 50g; Initiator: 5g; High temperature resistant modifier: 0.5g; Foaming agent: 10g; Cross-linking agent: 5g; Nucleating agent: 5g; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material.

[0053] The water bath polymerization reaction temperature is 120° C. and the time is 100 minutes.

[0054] The heating and foaming temperature is 250° C., and the foaming time is 1 hour.

[0055] When the material mixture is injected into the mold, the filling rate inside the mold is 80%.

[0056] The initiator is selected from azobisisobutyronitrile.

[0057] The blowing agent is selected from n-pentane.

[0058] The crosslinking agent is selected from isophthalic acid dienyl ester.

[0059] The nucleating agent is selected from titanium dioxide nanoparticles.

[0060] The high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is as follows: Slowly add 26g of 4-vinylbenzocyclobutene (CAS: 99717-87-0), 0.7g of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium (CAS: 12289-94-0), 50g of 4,4′-dimercaptostilbene (CAS: 614756-39-7), and 6g of sodium ethoxide into 300g of toluene, mix and stir at 75°C for 40min, and distill to remove toluene to obtain a high temperature resistant modifier.

[0061] Comparative Example 1 The difference from Example 1 is that no high temperature resistant modifier is used in the preparation process of PMI foam.

[0062] Comparative Example 2 The difference from Example 1 is that bis-(2-methylallyl)cyclooct-1,5-dieneruthenium is not used in the preparation process of the high temperature resistant modifier.

[0063] Comparative Example 3 The difference from Example 1 is that 4-vinylbenzocyclobutene is not used in the preparation process of the high temperature resistant modifier.

[0064] Test results: Table 1 Mechanical properties of foams in the examples Table 2 Mechanical properties of comparative foams It can be seen from the test results of the above examples and comparative examples that the strength, toughness and high temperature resistance of the PMI foam prepared in the examples are better than those of the PMI foam prepared in the comparative examples, which proves the excellent performance of the PMI foam prepared by the present invention.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-toughness, high-strength and high-temperature resistant PMI foam, characterized in that: The following steps are involved: Methacrylic acid, methacrylonitrile, initiator, high temperature resistant modifier, foaming agent, crosslinking agent and nucleating agent are added into the reaction kettle according to the mass proportions, wherein the mass ratio of each component is: Methacrylic acid: 40-70 parts; Methacrylonitrile: 30-50 parts; Initiator: 1-5 parts; High temperature resistant modifier: 0.1-0.5 parts; Foaming agent: 1-10 parts; Cross-linking agent: 1-5 parts; Nucleating agent: 1-5 parts; The mixture is mixed uniformly by mechanical stirring to obtain a material mixed liquid; The obtained material mixture is injected into a mold to carry out a water bath polymerization reaction; after the reaction is completed, it is heated and foamed to obtain a high-toughness, high-strength and high-temperature resistant PMI foam material; The high temperature resistant modifier is prepared by reacting 4-vinylbenzocyclobutene, bis-(2-methylallyl)cyclooctane-1,5-dieneruthenium and 4,4'-dimercaptostilbene.

2. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The water bath polymerization reaction temperature is 25-120° C. and the reaction time is 100-350 minutes.

3. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The heating and foaming temperature is 140-250° C., and the foaming time is 0.5-10 hours.

4. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: When the material mixture is injected into the mold, the filling rate inside the mold is 40%-80%.

5. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The initiator is selected from at least one of benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide and azobisisobutyronitrile.

6. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The foaming agent is selected from at least one of nitrogen, carbon dioxide, n-pentane and isopentane.

7. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The crosslinking agent is selected from at least one of divinylbenzene, trimethylolpropane triacrylate, bisphenol A diglycidyl ether, and isophthalic acid dienyl ester.

8. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The nucleating agent is selected from at least one of silicon dioxide nanoparticles, aluminum oxide nanoparticles, boron nitride nanoparticles, and titanium dioxide nanoparticles.

9. The high-toughness, high-strength, high-temperature-resistant PMI foam according to claim 1, characterized in that: The high temperature resistant modifier is benzocyclobutene-containing diphenylethylene, and its preparation method is as follows: Slowly add 13-26 parts of 4-vinylbenzocyclobutene, 0.05-0.7 parts of bis-(2-methylallyl)cyclooct-1,5-dieneruthenium, 25-50 parts of 4,4'-dimercaptostilbene, and 2-6 parts of sodium ethoxide into 200-300 parts of toluene, mix and stir at 65-75°C for 40-100 minutes, and remove toluene by distillation to obtain a high temperature resistant modifier.

Images