WO2020252967A1 - Method for preparing hyperbranched polysulfide - Google Patents

Abstract

A method for preparing a hyperbranched polysulfide based on selective mercapto-ene and mercapto-epoxy click chemistry. A difunctional glycidyl acrylate monomer and a trifunctional mercaptan are used as raw materials, and a one-pot method is used to synthesize the hyperbranched polysulfide, of which the skeleton and end groups are adjustable. The raw materials are easily obtainable, the steps are simple, the polymerization rate is fast and the controllability is good. The skeleton of the prepared hyperbranched polysulfide may be adjusted, and by using a monomer molar ratio, the end groups may be effectively controlled as mercapto or epoxy, both of which may be further subjected to functionalization modifications, thereby preparing hyperbranched polysulfides having specific properties.

Description

Method for preparing hyperbranched polysulfide Technical field

The invention relates to the field of organic polymers, in particular to a method for preparing hyperbranched polysulfide.

Background technique

Due to the existence of sulfur atoms, sulfur-containing hyperbranched polymers have special functions that conventional hyperbranched polymers (HBP) do not possess, and have received more and more attention. The sulfhydryl click chemistry reaction has gradually become the main reaction for the preparation of sulfur-containing hyperbranched polymers due to its high reactivity, mild and efficient reaction, and wide monomer applicability. At present, the preparation methods of hyperbranched polymers mainly include two methods, AB ₂ and A ₂ +B ₃ , and the synthesis of sulfur-containing hyperbranched polymers is mainly based on the AB ₂ method. Among them, Gao Chao of Zhejiang University (Han J, Zhao B, Tang A, et al. Polymer Chemistry, 2012, 3(7): 1918-1925.) used 3,6-dioxaoctane-1,8- Dimercapto and propargyl bromide were used as raw materials to prepare AB ₂ monomer with one end of mercapto group and one end of alkyne, and then the AB ₂ monomer was polymerized by mercapto-alkynes click chemistry to prepare hyperbranched polysulfide with end groups alkyne Ethers can be used in the fields of metal ion adsorption, oil resistance, and oxidation resistance resins; Gadwal et al. (Gadwal I, Binder S, Stuparu MC, et al. Macromolecules, 2014, 47(15): 5070-5080.) passed the series An AB ₂ monomer containing two epoxy groups and a mercapto group was prepared by organic synthesis, and then a hyperbranched polysulfide with epoxy end groups was prepared by the mercapto-epoxy click chemistry reaction; but due to the AB ₂ type monomer There are very few species and the monomer preparation process is cumbersome. However, the A ₂ + B ₃ polymerization system lacks selectivity and has the risk of gelation during the polymerization process, which severely limits the preparation and application of hyperbranched polysulfide. In addition, limited by the monomer structure and polymerization system, most of the currently reported AB ₂ and A ₂ +B ₃ systems can only prepare hyperbranched polysulfides with specific backbones and end groups, and it is difficult to simultaneously control the hyperbranched polysulfides. The backbone and terminal groups limit the functions and application fields of hyperbranched polysulfide.

Summary of the invention

In order to solve the above problems, the present invention provides a method for preparing hyperbranched polysulfide:

Using difunctional glycidyl acrylate monomers and trifunctional thiols as raw materials, a one-pot method is used to prepare hyperbranched polythioethers. The trifunctional trithiol monomers and difunctional glycidyl acrylate monomers The volume molar ratio is 1:0.8 to 2.4, preferably 1:2.0 to 2.4.

Further, the method is to mix a trifunctional trithiol monomer, a difunctional glycidyl acrylate monomer, a catalyst and a solvent, react for 2 to 48 hours and then purify to obtain a hyperbranched polysulfide.

Further, the added amount of the catalyst is 0.5-5 mol% of the monomer amount; the purification includes rotary evaporation and concentration, dissolution-precipitation operation, and vacuum drying of the precipitate.

Further, the concentration of the trifunctional trithiol monomer and the difunctional glycidyl acrylate monomer is in the range of 0.1-1.0 g mL ^-1 .

Further, the solvent includes tetrahydrofuran, dioxane, dimethyl sulfoxide and N,N-dimethylformamide; the catalyst includes triethylamine, dimethylaminopyridine, 1,8-bis Azabicyclo[5,4,0]undec-7-ene, 1,5,7-triazabicyclo[4.4.0]dec-5-ene; the temperature of the reaction is 20～ 100°C.

Further, the trifunctional trithiol monomer includes trimethylolpropane-tris(3-mercaptopropionate), 1,3,5-benzenetrithiol, tris(2-hydroxyethyl) iso Cyanurate-tris(3-mercaptopropionate), diethanolamine-tris(3-mercaptopropionate); difunctional glycidyl acrylate monomers include glycidyl methacrylate.

Another object of the present invention is to provide a hyperbranched polysulfide prepared according to any of the above methods.

Further, the hyperbranched polysulfide skeleton contains sulfide and hydroxyl, and the end groups can be effectively controlled to be mercapto groups or epoxy groups by the molar ratio of monomers, the number average molecular weight is 2.5-60 kDa, and the polydispersity index is 1.2-2.0. The Mark-Houwink index α is 0.2 to 0.5.

Further, the hyperbranched polysulfide has the following structure:

Further, the hyperbranched polysulfide has the following structure:

Advantages of the invention:

The present invention uses difunctional glycidyl acrylate compound as AC monomer (A represents acrylate group, C represents epoxy group), trifunctional thiol is B ₃ monomer, and one-pot synthesis of structural hyperbranched化polysulfide. The reactivity of acrylate double bond and mercapto group in AC monomer is much higher than epoxy group. By controlling the reaction conditions, at the beginning of the polymerization reaction, AC monomer and B ₃ monomer react to form CB ₂ or BC ₂ intermediate Then, it is further polymerized to obtain a hyperbranched polysulfide whose backbone and end groups can be controlled. The polymerization system is controllable and gelation is effectively avoided. The invention has easy-to-obtain raw materials, simple steps, fast polymerization rate and good controllability. By controlling the molar ratio of monomers, the end groups of the hyperbranched polymer can be adjusted to be mercapto groups or epoxy groups, and both can be further functionally modified. Compared with the traditional method, this method has the advantages of not easy to gel, simple and easy to operate, and high controllability.

Description of the drawings

Figure 1 is the infrared absorption spectrum of the mercapto-terminated hyperbranched polysulfide P3 and the monomer glycidyl methacrylate (GMA) prepared in Example 3.

Figure 2 is a hydrogen NMR spectrum of the mercapto-terminated hyperbranched polysulfide P3 and the monomer glycidyl methacrylate (GMA) prepared in Example 3.

Figure 3 is a GPC elution time curve of the mercapto-terminated hyperbranched polysulfide P3 prepared in Example 3.

4 is the infrared absorption spectrum of epoxy-terminated hyperbranched polysulfide P7 prepared in Example 7.

Figure 5 is a hydrogen nuclear magnetic spectrum of epoxy-terminated hyperbranched polysulfide P7 prepared in Example 7.

6 is the GPC elution time curve of epoxy-terminated hyperbranched polysulfide P7 prepared in Example 7.

Detailed ways

The present invention will be further described below in conjunction with specific implementation cases. It should be understood that the present invention is not limited to the following implementation cases, and the methods are regarded as conventional methods unless otherwise specified. The materials can be obtained from public commercial channels unless otherwise specified.

Cases 1-10 are the preparation cases of hyperbranched polysulfide.

Implementation case 1:

Combine 9.965g (25mmol) trimethylolpropane-tris(3-mercaptopropionate), 75mL tetrahydrofuran (THF), 3.56g (25mmol) glycidyl methacrylate and 0.1012g (1.0mmol) triethylamine once Add it to the reactor and react with N ₂ protection at room temperature for 24h; after the reaction, the reaction solution is concentrated by rotary evaporation, re-dissolved in chloroform and then precipitated in anhydrous ether. Repeat the dissolution-precipitation operation 3 times, and the precipitate is obtained after vacuum drying Colorless and viscous mercapto-terminated hyperbranched polysulfide P1 (9.50 g, yield 70.4%).

Implementation case 2:

Combine 9.965g (25mmol) trimethylolpropane-tris(3-mercaptopropionate), 75mL N,N-dimethylformamide (DMF), 3.56g (25mmol) glycidyl methacrylate and 0.1222g (1.0mmol) N,N-lutidine was added to the reactor at one time, and the reaction was protected by N ₂ at room temperature for 24h; after the reaction, the reaction solution was concentrated by rotary evaporation, re-dissolved in chloroform, and precipitated in anhydrous ether. Repeat The dissolution-precipitation operation was performed 3 times, and the precipitate was vacuum dried to obtain a colorless, viscous, mercapto-terminated hyperbranched polysulfide P2 (9.26 g, yield 68.5%).

Implementation case 3:

9.965g (25mmol) trimethylolpropane-tris(3-mercaptopropionate), 75mL DMF and 3.56g (25mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-bisaza Bicyclo[5,4,0]undec-7-ene (DBU) was added to the reactor at one time, and the reaction was protected by N ₂ at room temperature for 24h; after the reaction, the reaction solution was concentrated by rotary evaporation and re-dissolved in chloroform. After precipitation in anhydrous ether, the dissolution-precipitation operation was repeated 3 times, and the precipitate was vacuum dried to obtain a colorless viscous sulfhydryl-terminated hyperbranched polysulfide P3 (8.57 g, yield 63.4%).

Figure 1 is the infrared absorption spectrum of the mercapto-terminated hyperbranched polysulfide P3 and the monomer glycidyl methacrylate (GMA) prepared in Example 3, where the stretching vibration absorption peak of OH at 3505cm ^-1 in the P3 spectrum characteristic peaks, 2570cm ^-1 is a characteristic absorption peak at a mercapto group, 910cm ^-1 at the disappearance of epoxy, P3 is a proof of mercapto-terminated;

Figure 2 is the hydrogen NMR spectrum of the sulfhydryl-terminated hyperbranched polysulfide P3 and the monomer glycidyl methacrylate (GMA) prepared in Example 3. The proton signal peak of the double bond at 5.58-6.43 ppm disappears and at 1.65 ppm The proton signal of the sulfhydryl group is weakened, the characteristic absorption peak of epoxy at 3.28ppm disappears, and the proton signal of the methylene adjacent to the S atom at 2.48-2.85ppm increases, which further proves that the end group of P3 is a sulfhydryl group;

Figure 3 is the GPC elution time curve of the sulfhydryl-terminated hyperbranched polysulfide P3 prepared in Example 3. Using linear PS as a standard sample, the relative molecular weight of P3 was fitted from the GPC elution time curve M _w =7.6kDa, PDI=1.57 . Using light scattering-viscosity-GPC triple combination, combined with dn/dc value of 0.0580, the absolute molecular weight of P3 is 28.8kDa, Mark-Houwink index α is 0.342, which is within the range of 0.2-0.5 of hyperbranched polymer , Which proves that P3 has a highly branched structure.

Implementation case 4:

Combine 4.357g (25mmol) 1,3,5-benzenetrithiol, 40mL DMF, 3.56g (25mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-bisazabicyclo (5, 4,0] Undec-7-ene (DBU) was added to the reactor at a time, and the reaction was protected by N ₂ at room temperature for 24 hours; after the reaction, the reaction solution was concentrated by rotary evaporation and re-dissolved in chloroform Precipitating in anhydrous ether, repeating the dissolution-precipitation operation 3 times, the precipitate was vacuum dried to obtain a colorless viscous sulfhydryl-terminated hyperbranched polysulfide P4 (8.57 g, yield 63.4%).

Implementation case 5:

Combine 13.14g (25mmol) tris (2-hydroxyethyl) isocyanurate-tris (3-mercaptopropionate) (THMP), 83mL DMF, 3.56g (25mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) was added to the reactor at once, and the reaction was protected by N ₂ at room temperature for 24h; after the reaction, the reaction The liquid was concentrated by rotary evaporation, re-dissolved in chloroform, and precipitated in anhydrous ether. The dissolution-precipitation operation was repeated 3 times. After the precipitate was dried in vacuum, a colorless viscous sulfhydryl-terminated hyperbranched polysulfide P6 (10.80g, yield was 64.7). %).

Implementation case 6:

9.965g (25mmol) trimethylolpropane-tris(3-mercaptopropionate), 75mL tetrahydrofuran, 7.11g (50mmol) glycidyl methacrylate and 0.1012g (1.0mmol) triethylamine were added to the reaction at one time In the vessel, the reaction was protected by N ₂ at room temperature for 24 hours; after the reaction, the reaction solution was concentrated by rotary evaporation, re-dissolved in chloroform and precipitated in anhydrous ether. Repeated dissolution-precipitation operation 3 times, the precipitate was dried in vacuo to obtain colorless viscosity Epoxy-terminated hyperbranched polysulfide P5 (9.92 g, yield 58.3%).

Implementation case 7:

9.965g (25mmol) trimethylolpropane-tris(3-mercaptopropionate), 75mL DMF, 7.11g (50mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-bisaza Bicyclo[5,4,0]undec-7-ene was added to the reactor at one time, and the reaction was protected by N ₂ at room temperature for 24h; after the reaction, the reaction solution was concentrated by rotary evaporation, re-dissolved in chloroform, and then dissolved in anhydrous ether. In the middle of precipitation, the dissolution-precipitation operation was repeated 3 times, and the precipitate was vacuum dried to obtain colorless, viscous-terminated epoxy hyperbranched polysulfide P7 (10.14 g, yield 59.4%).

FIG 4 is an end P7 epoxidized hyperbranched polythioethers infrared absorption spectrum of FIG. 7 embodiment Case prepared, wherein absorption peak at 3505cm ^-1 is the stretching vibration of OH, 910cm ^-1 is a characteristic peak at an epoxy, 2540cm ^-1 The characteristic absorption peak of the sulfhydryl group disappeared, proving that P7 is epoxy-terminated;

Figure 5 is the hydrogen NMR spectrum of the epoxy-terminated hyperbranched polysulfide P7 prepared in Example 7. The proton signal peak of the double bond at 5.58-6.43 ppm disappears, the proton signal of the mercapto group at 1.65 ppm disappears, and the epoxy at 3.28 ppm The characteristic absorption peak of P7 is weakened, and the methylene proton signal adjacent to the S atom at 2.48-2.85ppm is strengthened, which further proves that P7 is epoxy-terminated;

Figure 6 is the GPC elution time curve of epoxy-terminated hyperbranched polysulfide P7 prepared in Example 7. Using linear PS as a standard sample, the relative molecular weight of P7 is fitted from the GPC elution time curve to M _w =6.0kDa, PDI = 1.50; using light scattering-viscosity-GPC triple combination, combined with dn/dc value of 0.0580, the absolute molecular weight of P7 is 25.3kDa respectively; Mark-Houwink index α is 0.394, which is 0.2-0.5 of hyperbranched polymer Within the range, it is proved that P7 has the expected highly branched structure.

Implementation case 8:

Combine 4.357g (25mmol) 1,3,5-benzenetrithiol, 57mL tetrahydrofuran, 7.11g (50mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-bisazabicyclo (5, 4,0] Undec-7-ene (DBU) was added to the reactor at one time, and the reaction was protected by N ₂ at room temperature for 24 hours; after the reaction, the reaction solution was concentrated by rotary evaporation, re-dissolved in chloroform and precipitated in anhydrous ether , The dissolution-precipitation operation was repeated 3 times, and the precipitate was vacuum dried to obtain a colorless, viscous epoxy-terminated hyperbranched polysulfide P8 (8.52 g, yield 74.3%).

Implementation case 9:

Combine 13.14g (25mmol) tris(2-hydroxyethyl) isocyanurate-tris(3-mercaptopropionate) (THMP), 100mL tetrahydrofuran, 7.11g (50mmol) glycidyl methacrylate and 0.1522g (1.0mmol) 1,8-bisazabicyclo[5,4,0]undec-7-ene was added to the reactor at one time, and the reaction was protected by N ₂ at room temperature for 24h; after the reaction, the reaction solution was evaporated Concentrate, re-dissolve in chloroform and precipitate in anhydrous ether. Repeat the dissolution-precipitation operation 3 times. After the precipitate is vacuum dried, a colorless and viscous epoxy-end hyperbranched polysulfide P9 (12.41g, yield 61.3%) ).

The structural parameters of the hyperbranched polysulfide P1-P9 prepared in Examples 1-9 are shown in the following table.

Table 1

Note:

The molar ratio is the molar ratio of the trifunctional trithiol monomer and the difunctional glycidyl acrylate monomer.

M _{w, GPC} (kg/mol) and M _{w, GPC} /M _{n, GPC} were measured by gel permeation chromatography (Waters GPC 486), using linear polystyrene (PS) as the standard sample and tetrahydrofuran (THF) as Eluent.

M _{w, MALLS} (kg/mol) and α (Mark-Houwink index) are measured by the gel permeation chromatography-multi-angle laser light scattering-viscosity triple system (GPC-MALLS, DAWN HELEOS II System). N,N-Dimethylformamide (DMF) is the eluent, and the specific refractive index increase (dn/dc) of the sample is measured by using the Wyatt Optilab refractive index detector (λ=658nm); the viscosity detector is used to characterize the polymerization The original data is processed with Astra VI software, the absolute weight average molecular weight M _w,MALLS (kg/mol) of the sample is fitted by dn/dc, and the mark is fitted by the intrinsic viscosity and absolute weight average molecular weight. Howenk Index α.

It can be seen from the above table that the hyperbranched polysulfide prepared by the method of the present invention has a highly branched structure, and according to the method of the present invention, the end group of the hyperbranched polymer can be adjusted to be a mercapto group by changing the molar ratio of monomers. Or epoxy groups.

Claims (10)

1. A method for preparing hyperbranched polysulfide, which is characterized in that, using difunctional glycidyl acrylate monomers and trifunctional mercaptan as raw materials, the hyperbranched polysulfide is prepared by a one-pot method. The molar ratio of the trithiol monomer and the difunctional glycidyl acrylate monomer is 1:0.8 to 2.4, preferably 1:2.0 to 2.4.
2. The method for preparing hyperbranched polysulfide according to claim 1, wherein the method is to mix a trifunctional trithiol monomer, a difunctional glycidyl acrylate monomer, a catalyst and a solvent After reaction for 2～48h, it is purified to obtain hyperbranched polysulfide.
3. The method for preparing hyperbranched polysulfide according to claim 2, wherein the added amount of the catalyst is 0.5-5 mol% of the monomer amount; the purification is after rotary evaporation and concentration, and then dissolving- Precipitation operation, the precipitate is vacuum dried.
4. The method for preparing hyperbranched polysulfide according to claim 1, wherein the concentration of the trifunctional trithiol monomer and difunctional glycidyl acrylate monomer is 0.1-1.0 g mL ^-1 range.
5. The method for preparing hyperbranched polysulfide according to claim 2, wherein the solvent includes tetrahydrofuran, dioxane, dimethyl sulfoxide and N,N-dimethylformamide; The catalysts described include triethylamine, dimethylaminopyridine, 1,8-bisazabicyclo[5,4,0]undec-7-ene, 1,5,7-triazabicyclo[4.4 .0] Dec-5-ene; The temperature of the reaction is 20-100°C.
6. The method for preparing hyperbranched polysulfide according to claim 1, wherein the trifunctional trithiol monomer comprises trimethylolpropane-tris(3-mercaptopropionate), 1 ,3,5-Benzenetrithiol, tris(2-hydroxyethyl)isocyanurate-tris(3-mercaptopropionate), diethanolamine-tris(3-mercaptopropionate); difunctional Glycidyl acrylate monomers include glycidyl methacrylate.
7. A hyperbranched polysulfide, which is characterized in that it is prepared according to any method of claims 1 to 6.
8. A hyperbranched polysulfide, characterized in that the hyperbranched polysulfide skeleton contains a sulfide and a hydroxyl group, and the end group can be effectively controlled to be a mercapto group or an epoxy group by the monomer molar ratio, and the number average molecular weight is 2.5-60kDa. The sex index is 1.2 to 2.0, and the Mark-Houwink index α is 0.2 to 0.5.
9. The hyperbranched polysulfide according to claim 7, wherein the hyperbranched polysulfide has the following structure:

   
10. The hyperbranched polysulfide according to claim 7, wherein the hyperbranched polysulfide has the following structure:

    

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