A sulfur-containing intrinsic flame-retardant bismaleimide material and a preparation method thereof
Sulfur-containing intrinsically flame-retardant bismaleimide materials were prepared by copolymerizing elemental sulfur with bismaleimide monomers under mild conditions. This solved the problems of flammability and high production cost of existing materials, and achieved low-cost, high-efficiency flame retardant effect and processing performance.
Patent Information
- Application Number
- CN202310987181.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-07
- Publication Date
- 2025-11-25
- Estimated Expiration
- 2043-08-07
AI Technical Summary
Existing bismaleimide materials are flammable and have poor fire safety. Traditional modification methods suffer from problems such as high cost, high molding temperature, and long curing time.
A sulfur-rich polymer was synthesized in one step by anionic hybrid copolymerization of elemental sulfur and bismaleimide monomers under mild conditions, and sulfur-containing intrinsically flame-retardant bismaleimide materials were prepared.
It achieves low-cost, low-temperature synthesis, and the material has excellent flame-retardant properties and flexibility, shortening the production cycle.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of polymer synthesis, and particularly relates to a sulfur-containing intrinsic flame-retardant bismaleimide material and a preparation method thereof. BACKGROUND
[0002] Bismaleimide (BMI) is a typical thermosetting resin, which has a wide application in the field of organic chemical synthesis and material preparation due to its high reactivity and diverse reaction forms. The monomer can be homopolymerized at 180 DEG C to form a three-dimensional network, which has excellent high-temperature resistance, low-temperature resistance and radiation resistance, and is widely used in the fields of machinery, electronics and aerospace due to its outstanding dimensional stability and mechanical properties.
[0003] According to the structure of the BMI monomer, there are still problems of flammability and poor fire safety. Meanwhile, the high crosslinking density and strong polar carbonyl group of the BMI material make the material itself extremely brittle. At present, the modification of the BMI material can be generally divided into two types: intrinsic flame retardant and non-intrinsic flame retardant. The non-intrinsic flame retardant usually adds flame-retardant small molecules such as aluminum phosphate, cage polysilsesquioxane, two-dimensional sheet graphene and inorganic boron nitride hybrid to the BMI system to increase the flame-retardant performance; the intrinsic flame-retardant material is covalently bonded to the flame-retardant molecule and the BMI monomer, such as amino or allyl modified phosphate, isocyanurate, silsesquioxane, etc. The intrinsic flame-retardant material system has a low phase separation phenomenon and can provide better flame-retardant effect.
[0004] Although the existing methods can introduce various kinds of flame-retardant factors into the polymer, these methods have defects to some extent. For example, the halogen-containing BMI flame-retardant material will cause leakage pollution; the phosphorus-containing and nitrogen-containing BMI flame-retardant material has a low smoke generation rate, but the synthesis cost of the monomer is high. Meanwhile, the molding temperature of the traditional modified BMI material is generally high, the curing time is long, and the production cost is high. Therefore, it is always a key and difficulty to find a new intrinsic BMI material with low raw material price, simple process and short production cycle. SUMMARY
[0005] In order to solve the defects existing in the synthesis path of the existing BMI material, the present application proposes to synthesize a sulfur-rich polymer by using elemental sulfur and bismaleimide monomer under mild reaction conditions by adopting an anion hybrid copolymerization method. The sulfur-rich polymer synthesized by the present application has the characteristics of mild reaction conditions, simple processing and excellent flame-retardant effect.
[0006] In order to achieve the above purpose, the present application realizes the following technical scheme:
[0007] The application relates to a preparation method of a sulfur-containing intrinsic flame-retardant bismaleimide material.
[0008] Further, the copolymerization reaction environment is a dry environment protected by inert gas, the reaction temperature is 0-70 DEG C, and the reaction time is 3-24 h.
[0009] The feeding mass ratio of the synthesized sulfur-rich polymer monomer is 50-80 wt% of bismaleimide monomer and 20-50 wt% of elemental sulfur, and the material is formed through hot pressing.
[0010] The bismaleimide is 4,4'-bismaleimide diphenyl methane (BMI), bismaleimide polyethylene glycol (Bis-Mal-PEG1) or diphenyl methane bismaleimide (BMIDM).
[0011] The solvent is one of N,N-dimethylformamide (DMF), N,N-dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP), and the feeding amount is consistent with the mass of the monomer.
[0012] The hot pressing temperature is 130 DEG C, the hot pressing time is 30 min, and the pressure is 10 MPa.
[0013] Beneficial effects:
[0014] In the application, the raw material elemental sulfur S8 is a natural product, is environment-friendly and harmless, and is low in price.
[0015] The preparation method of the sulfur-containing intrinsic flame-retardant bismaleimide material provided by the application is a one-step synthesis, and no catalyst is required in the reaction.
[0016] The preparation method of the sulfur-containing intrinsic flame-retardant bismaleimide material provided by the application has relatively mild polymerization reaction conditions, and the polymerization can be carried out under a reaction condition of less than 70 DEG C.
[0017] In the product of the preparation method of the sulfur-containing intrinsic flame-retardant bismaleimide material provided by the application, a large amount of sulfur elements can rapidly undergo oxidation-reduction reaction in a combustion process to generate a sulfur oxide protective layer and non-combustible gas, thereby providing excellent flame-retardant performance for the material; meanwhile, the S-S chain segment with good flexibility improves the processing performance of the material, and greatly reduces the production cycle. DETAILED DESCRIPTION
[0018] Figure 1 It is the FTIR spectrum of the product P(S-BMI) of Example 1.
[0019] Figure 2TGA curve of the product P(S-BMI) of Example 1 and elemental sulfur.
[0020] Figure 3 FTIR spectrum of the product P(S-BMI) of Example 3.
[0021] Figure 4 DSC curve of the product P(S-BMI) of Example 3 and elemental sulfur.
[0022] Figure 5 HRR curve of the product Poly(S-BMI) of Example 1 and Example 6.
[0023] Figure 6 CCT test residual carbon content of the product Poly(S-BMI) of Example 1 and Example 6.
[0024] Figure 7 FTIR spectrum of the product Poly(S-BMIDM) of Example 4.
[0025] Figure 8 Actual figure of the secondary vertical combustion test of Example 6. DETAILED DESCRIPTION
[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the embodiments of the present application and the accompanying drawings. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor fall within the scope of protection of the present application.
[0027] Example 1
[0028] 2.867g of BMI, 1.024g of elemental sulfur powder and 4g of DMSO were weighed into a 50mL flask, mixed and stirred under inert gas protection at room temperature for 12h of reaction. After the reaction was completed, the mixture was ground and repeatedly precipitated and washed, and after drying in a vacuum oven, the yield reached 99.3wt%.
[0029] Comparative Example 1
[0030] 2.867g of BDDA (1,4-butanediol diacrylate), 1.024g of elemental sulfur powder and 4g of DMSO were weighed into a 50mL flask, mixed and stirred under inert gas protection at room temperature for 12h of reaction. After the reaction was completed, the mixture was ground and repeatedly precipitated and washed, and after drying in a vacuum oven, the yield reached 19.3wt%.
[0031] Example 2
[0032] Take 2.306g Bis-Ma1-PEG1, 0.512g elemental sulfur powder, 3g DMF in a 50mL flask, under inert gas protection, 40℃ mixing stirring reaction 6h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 96.7wt%.
[0033] Example 3
[0034] Take 2.150g BMI, 1.024g elemental sulfur powder, 3g DMSO in a 50mL flask, under inert gas protection, 50℃ mixing stirring reaction 3h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 98.1wt%.
[0035] Example 4
[0036] Take 1.333g BMIDM, 0.512g elemental sulfur powder, 2g NMP in a 50mL flask, under inert gas protection, 50℃ mixing stirring reaction 6h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 93.6wt%.
[0037] Example 5
[0038] Take 2.867g BMIDM, 1.024g elemental sulfur powder, 4g DMSO in a 50mL flask, under inert gas protection, room temperature mixing stirring reaction 12h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 93.3wt%.
[0039] Example 6
[0040] Take 1.433g BMI, 1.024g elemental sulfur powder, 3g DMSO in a 50mL flask, under inert gas protection, 35℃ mixing stirring reaction 12h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 94.3wt%.
[0041] Table 1 is the UV-94 standard flame retardant test results and mechanical property results of the relevant examples.
[0042] Table 1
[0043]
[0044] Example 7
[0045] Take 2.867 g BMI, 1.024 g elemental sulfur powder, 4 g NMP in a 50 mL flask, under inert gas protection, room temperature mixing stirring reaction 12 h, after the reaction, the mixture is ground and repeatedly precipitated and washed, and dried in a vacuum oven to give a yield of 95.6 wt%.
[0046] The above merely describes a preferred embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical scope disclosed by the present application according to the technical solutions and the inventive concept of the present application, which should be covered within the protection scope of the present application.
Claims
1. A process for the preparation of a sulfur-containing intrinsic flame retardant bismaleimide material, characterized in that, The preparation method is: under the condition of the existence of a solvent, bismaleimide monomer and elemental sulfur are combined into a self-catalytic copolymerization system under a mild heating environment, a sulfur-containing polymer is synthesized by one-step hybrid copolymerization reaction, and a sulfur-containing intrinsic flame-retardant bismaleimide material is obtained by hot pressing. The solvent is one of N,N-dimethylformamide, N,N-dimethyl sulfoxide or N-methyl pyrrolidone, and the feeding amount is consistent with the mass of the monomer. The sulfur-containing intrinsic flame-retardant bismaleimide material has a mass percentage composition of 50-80 wt% of bismaleimide monomer and 20-50 wt% of elemental sulfur.
2. The process for the preparation of a sulfur-containing intrinsic flame retardant bismaleimide material according to claim 1, characterized in that, The bismaleimide monomer is 4,4'-bismaleimide diphenyl methane BMI or bismaleimide polyethylene glycol Bis-Mal-PEG1.
3. The process for the preparation of a sulfur-containing intrinsic flame retardant bismaleimide material according to claim 1, characterized in that, The hybrid copolymerization reaction environment is a dry environment protected by inert gas.
4. The process for the preparation of a sulfur-containing intrinsic flame retardant bismaleimide material according to claim 1, characterized in that, The hybrid copolymerization reaction temperature is 0-70 DEG C, and the copolymerization reaction time is 3-24 h.
5. The process for preparing a sulfur-containing intrinsic flame retardant bismaleimide material according to claim 1, characterized in that, The molding temperature is 130 DEG C, the molding pressure is 10 MPa, and the molding time is 30 min.