Method for preparing sulfur-containing polymer from sulfur, olefin and isocyanate ternary polymerization system

Abstract

The invention belongs to the field of polymer synthesis, and particularly relates to a method for preparing a sulfur-containing polymer from a sulfur, olefin and isocyanate ternary polymerization system. In a reaction system, polymerization is completed through addition reaction of double bonds and sulfur, and polymerization is completed through addition of isocyanate groups and sulfur and hydrogen abstracting reaction of the isocyanate groups and the double bonds. The polymerization reaction can be carried out only by a small amount of basic catalyst, the reaction condition is mild, and the monomer adaptability is high. The synthesized polymer has various dynamic bonds, such as polysulfide bonds, thionocarbamate and ester bonds, so that the polymer has good self-repairing capability. The prepared polymer can repair mechanical damage at a room temperature in an ultrafast manner, and the repaired material still has good mechanical properties. In addition, the polymer also has the advantages of ultraviolet resistance and high transmittance in a near-infrared region, and has a good application prospect in the fields of ultraviolet-resistant and infrared-resistant lenses and the like.

Description

Technical Field

[0001] The invention belongs to the field of polymer synthesis, and in particular relates to a method for preparing a sulfur-containing polymer by a ternary copolymerization system of sulfur, olefin and isocyanate. Background Art

[0002] Sulfur is a byproduct of oil refining. Every year, it is mined and stored in large quantities along with the production of oil. Elemental sulfur is flammable and can easily cause fires. At the same time, exposed elemental sulfur is easily oxidized into acid rain, causing serious environmental pollution and safety hazards. Using elemental sulfur as a sulfur source to prepare sulfur-containing polymers can not only solve the problem of excess sulfur, but also have the potential to prepare polymer materials with excellent performance.

[0003] At present, the preparation of sulfur-containing polymers directly using elemental sulfur as the sulfur source mainly includes the reverse vulcanization of elemental sulfur and olefin monomers, the multi-component copolymerization of elemental sulfur, alcohol and isonitrile, the ring-opening copolymerization of elemental sulfur and ring sulfur, and the anionic hybrid copolymerization of elemental sulfur and acrylate. Although these methods can introduce sulfur into the polymer network, they also have defects. For example, the price of isonitrile and ring sulfur monomers is expensive, the synthesis is difficult, and it is not conducive to large-scale production; the multi-component copolymerization of elemental sulfur, alcohol and isonitrile can only synthesize linear polymers containing C=S bonds, so the mechanical properties of such polymers are poor; the reverse vulcanization reaction of elemental sulfur needs to be carried out at a temperature above 130°C, and toxic gas H2S will be generated during the reaction; the mechanical properties of the materials prepared by the anionic hybrid copolymerization of sulfur and acrylate cannot meet the application requirements. Summary of the invention

[0004] The present invention provides a method for preparing a sulfur-containing polymer from a ternary copolymerization system consisting of sulfur, olefins and isocyanates. The present invention has discovered a completely new reaction mechanism: elemental sulfur reacts with olefins to generate polythioethers. Due to the unstable active α hydrogen on the polythioethers, the polythioethers can react with isocyanates to generate polythioethers with thiocarbamates. The groups that lose active hydrogen will be connected to another polythioether, thereby constructing a cross-linked network (see the specific process). Figure 1 ).

[0005] In order to achieve the above objectives, the present invention is implemented by the following technical solutions:

[0006] The method for preparing sulfur-based polymers by terpolymerization of sulfur, olefin and isocyanate is as follows: reacting olefin monomer, elemental sulfur and isocyanate monomer under the action of a small amount of alkaline catalyst.

[0007] The reaction temperature is room temperature-50°C and the reaction time is 12-24h.

[0008] The feed weight ratio of synthesizing sulfur-containing polymer monomers is 30-40wt% of olefin monomers, 20-30wt% of elemental sulfur, 30-40wt% of isocyanate monomers and 0.1-0.8wt% of catalysts.

[0009] The olefin monomers are 2-phenylethyl acrylate PEA, chloroethyl acrylate ClEA, isobornyl acrylate IBOA, and pentaerythritol triacrylate PETA.

[0010] The isocyanate monomers are n-butyl isocyanate BuI, cyclopentyl isocyanate CPI, benzyl isocyanate BnI, pentamethylene diisocyanate PDI, isophorone diisocyanate IPDI, diphenylmethane diisocyanate MDI, and meta-xylyl diisocyanate XDI.

[0011] The catalyst is 1,4-diazabicyclo[2.2.2]octane DABCO or 1,5-diazabicyclo[4.3.0]-5-nonene DBN.

[0012] Beneficial effects:

[0013] The raw material elemental sulfur in the present invention provides abundant SS bonds for the polymer, thereby enhancing the dynamic exchange capacity of the polymer and prolonging the service life of the polymer.

[0014] The invention has simple synthesis steps and can easily prepare highly cross-linked sulfur-based polymers.

[0015] The method for preparing sulfur-containing polymers based on a completely new mechanism provided by the present invention has a wide range of selectable monomers, and various active olefin monomers and isocyanate monomers can participate in the terpolymerization reaction.

[0016] The method for preparing sulfur-containing polymers based on a completely new mechanism provided by the present invention has mild polymerization reaction conditions.

[0017] The sulfur-containing polymer provided by the present invention is prepared based on a completely new mechanism. Due to the presence of polysulfide bonds and thiocarbamate bonds in the polymer, the material can ultra-fast repair mechanical damage at room temperature. In addition, the material has excellent mechanical properties, repeatable processing performance, UV resistance and high infrared transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the terpolymerization reaction of sulfur, olefin and isocyanate.

[0019] Figure 2 The product P(S-ClEA-BuI) of Example 2, the self-polymer of n-butyl isocyanate (PBuI) of Comparative Example 1 and the product of n-butyl isocyanate (BuI) 1 H-NMR spectrum.

[0020] Figure 3 The product P(S-ClEA-BnI) of Example 3, the benzyl isocyanate self-polymer (PBnI) of Comparative Example 2 and the benzyl isocyanate (BnI) 1 H-NMR spectrum.

[0021] Figure 4 FTIR spectra of the product P(S-ClEA-BuI) of Example 2 and the product P(S-ClEA-BnI) of Example 3.

[0022] Figure 5 DEPT-NMR spectra of the product P(S-ClEA-BuI) of Example 2 and the product P(S-ClEA) of Comparative Example 3.

[0023] Figure 6 DEPT-NMR spectra of the product P(S-ClEA-BnI) of Example 3 and the product P(S-ClEA) of Comparative Example 3.

[0024] Figure 7 The figure is a curve of the conversion rate of olefin and isocyanate in the product P(S-ClEA-BnI) of Example 3 over time.

[0025] Figure 8 1 and 1 , which are the tensile stress-strain curves of the product P (S-PETA-PDI) of Example 6 and the product P (S-PETA) of Comparative Example 4.

[0026] Fig. 9 The degradation test results of the product P (S-PETA-PDI) of Example 6 and the product P (S-PETA) of Comparative Example 4 in an aqueous solution at pH = 1 are shown.

[0027] Fig.10 FTIR spectra of the product P (S-PETA-PDI) and PDI monomer in Example 6.

[0028] Fig.11 The transmittance curves of the product P (S-PETA-PDI) of Example 6 and the product P (S-PETA) of Comparative Example 4 are shown.

[0029] Fig.12 Schematic diagram of the process of ultrafast self-repairing of the product P (S-PETA-PDI) of Example 6 at room temperature after shearing.

[0030] Fig.13 This is the stress-strain curve of the product P (S-PETA-PDI) in Example 6 before and after self-repair. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention and the accompanying drawings. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] Take 0.48g of elemental sulfur, 0.5608g of isobornyl acrylate (IBOA), 0.5957g of n-butyl isocyanate (BuI) and 20μL DABCO (2.1mg) in a 10mL flask, mix and stir at room temperature under inert gas protection for 24h. After the reaction, the mixture is precipitated and washed with methanol solvent until the methanol solvent is colorless and transparent. The yield after drying in a vacuum oven is 98.3wt%.

[0034] Example 2

[0035] Weigh 0.48 g of elemental sulfur, 0.6006 g of chloroethyl acrylate (ClEA), 0.5957 g of n-butyl isocyanate (BuI) and 10 μL of DBN into a 10 mL flask, and stir and react at 35 °C under inert gas protection for 20 h. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 98.5 wt%.

[0036] Comparative Example 1

[0037] Weigh 0.5957 g of n-butyl isocyanate (BuI) and 10 μL of DBN into a 10 mL flask, mix and stir at 35° C. for 20 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. After drying in a vacuum oven, the yield reaches 99.3 wt% to obtain n-butyl isocyanate self-polymer (PBuI).

[0038] Example 3

[0039] Weigh 0.48 g of elemental sulfur, 0.6006 g of chloroethyl acrylate (ClEA), 0.7658 g of benzyl isocyanate (BnI) and 10 μL of DBN into a 10 mL flask, and stir and react at 50 ° C under inert gas protection for 24 h. After the reaction, the mixture is precipitated and washed with methanol solvent until the methanol solvent is colorless and transparent. The yield after drying in a vacuum oven is 93.4 wt%.

[0040] Comparative Example 2

[0041] 0.7658 g of benzyl isocyanate (BnI) and 10 μL of DBN were weighed into a 10 mL flask, and the mixture was stirred and reacted at 50° C. for 24 h under inert gas protection. After the reaction, the mixture was precipitated and washed with methanol solvent until the methanol solvent was colorless and transparent. After drying in a vacuum oven, the yield reached 99.7 wt %, and benzyl isocyanate self-polymer (PBnI) was obtained.

[0042] Comparative Example 3

[0043] Weigh 0.48 g of elemental sulfur, 0.6006 g of chloroethyl acrylate (ClEA) and 10 μL of DABCO into a 10 mL flask, mix and stir at 35 °C for 24 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 96.4 wt%.

[0044] Example 4

[0045] Weigh 0.48 g of elemental sulfur, 0.6126 g of 2-phenylethyl acrylate (PEA), 0.7258 g of cyclopentyl isocyanate (CPI) and 10 μL of DBN into a 10 mL flask, and stir and react at 50 ° C under inert gas protection for 20 h. After the reaction, the mixture is precipitated and washed with methanol solvent until the methanol solvent is colorless and transparent. The yield after drying in a vacuum oven is 98.6 wt%.

[0046] Example 5

[0047] Weigh 0.48 g of elemental sulfur powder, 0.4904 g of pentaerythritol triacrylate (PETA), 0.7258 g of cyclopentyl isocyanate (CPI) and 10 μL of DBN into a 10 mL flask, and stir and mix at room temperature for 12 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 97.6 wt%.

[0048] Example 6

[0049] Weigh 0.48 g of elemental sulfur, 0.4904 g of pentaerythritol triacrylate (PETA), 0.38 g of pentamethylene diisocyanate (PDI) and 10 μL of DABCO into a 10 mL flask, mix and stir at room temperature under inert gas protection for 15 h, precipitate and wash the mixture with methanol solvent until the methanol solvent is colorless and transparent, and the yield after drying in a vacuum oven is 98.6 wt%.

[0050] Example 7

[0051] Weigh 0.48 g of elemental sulfur, 0.4904 g of pentaerythritol triacrylate (PETA), 0.4705 g of isophorone diisocyanate (IPDI) and 10 μL of DABCO into a 10 mL flask, and stir and react at room temperature for 12 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 94.6 wt%.

[0052] Example 8

[0053] Weigh 0.48 g of elemental sulfur, 0.4904 g of pentaerythritol triacrylate (PETA), 0.4174 g of diphenylmethane diisocyanate (MDI) and 10 μL of DABCO into a 10 mL flask, and stir and react at room temperature for 12 h under the protection of inert gas. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 98.6 wt%.

[0054] Example 9

[0055] Weigh 0.48 g of elemental sulfur, 0.4904 g of pentaerythritol triacrylate (PETA), 0.4136 g of meta-xylylene diisocyanate (XDI) and 10 μL of DABCO into a 10 mL flask, and stir and react at room temperature for 12 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 93.5 wt%.

[0056] Comparative Example 4

[0057] Weigh 0.48 g of elemental sulfur, 0.4904 g of pentaerythritol triacrylate (PETA) and 10 μL of DABCO into a 10 mL flask, and stir and react at room temperature for 12 h under inert gas protection. After the reaction, precipitate and wash the mixture with methanol solvent until the methanol solvent becomes colorless and transparent. The yield after drying in a vacuum oven is 98.8 wt%.

[0058] Performance test: tensile performance and self-repair efficiency tests were conducted at 25°C. The data are shown in Table 1.

[0059] Table 1 Tensile properties and self-repairing efficiency of the examples

[0060] Example Tensile strength(MPa) Elongation at break (%) Self-repair efficiency (%) 5 34.15±2.94 25.15±3.42 94 6 42.77±3.74 20.96±2.59 97 7 41.93±1.36 22.14±2.54 99 8 38.56±2.42 24.24±2.12 98 9 49.78±4.14 18.69±3.15 97 Comparative Example 4 7.59±3.13 96.78±4.12 20

[0061] Note: Three groups of control experiments were established in the test embodiment; the self-repairing efficiency test was shear and the ratio of mechanical properties before and after repair.

[0062] Performance test: The transmittance test was carried out at 25°C. The data is shown in Table 2.

[0063] Table 2 Ultraviolet and infrared transmittance of the examples

[0064] Example UV transmittance (%) Infrared transmittance (%) 5 <5 75 6 <5 82 7 <5 84 8 <5 81 9 <5 85 Comparative Example 4 <5 48

[0065] Note: Three groups of control experiments were established in the test examples.

[0066] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a sulfur-containing polymer by a ternary copolymerization system of sulfur, olefin and isocyanate, characterized in that: The method comprises the following steps: adding an organic base catalyst under a nitrogen atmosphere, and reacting an olefin monomer, elemental sulfur and isocyanate monomer to form a ternary copolymerization system to obtain a sulfur-containing polymer.

2. The method for preparing sulfur-containing polymers by the ternary copolymerization system of sulfur, olefin and isocyanate according to claim 1, characterized in that: The ternary copolymerization system is composed of 0.1-0.8 wt% of an organic base catalyst, 30-40 wt% of an olefin monomer, 20-30 wt% of elemental sulfur and 30-40 wt% of an isocyanate monomer in terms of mass percentage.

3. The method for preparing sulfur-containing polymers by the ternary copolymerization system of sulfur, olefin and isocyanate according to claim 1, characterized in that: The olefin monomers are: 2-phenylethyl acrylate PEA, chloroethyl acrylate CIEA, isobornyl acrylate IBOA, and pentaerythritol triacrylate PETA.

4. The method for preparing sulfur-containing polymers by using a ternary copolymerization system of sulfur, olefin and isocyanate according to claim 1, characterized in that: The isocyanate monomers are: n-butyl isocyanate BuI, cyclopentyl isocyanate CPI, benzyl isocyanate BnI, pentamethylene diisocyanate PDI, isophorone diisocyanate IPDI, diphenylmethane diisocyanate MDI, and meta-xylyl diisocyanate XDI.

5. The method for preparing sulfur-containing polymers by using a ternary copolymerization system of sulfur, olefin and isocyanate according to claim 1, characterized in that: The organic base catalyst is 1,4-diazabicyclo[2.2.2]octane DABCO or 1,5-diazabicyclo[4.3.0]-5-nonene DBN.

6. The method for preparing sulfur-containing polymers by using a ternary copolymerization system of sulfur, olefin and isocyanate according to claim 1, characterized in that: The reaction temperature is room temperature-50°C, and the reaction time is 12-24h.

Images