Double-end arylamine comb-type polyether toughened epoxy resin and preparation method thereof

Abstract

The invention relates to the technical field of epoxy resin, and discloses double-end arylamine comb-type polyether toughened epoxy resin and a preparation method thereof.The preparation method comprises the steps that S, S '-di (alpha, alpha'-dimethyl-alpha ''-acetic acid) trithiocarbonate and oxycarbonyl-4-hydroxyaniline are reacted, a novel RAFT reagent is obtained, and the double-end arylamine comb-type polyether toughened epoxy resin is obtained; and finally, carrying out trifluoroacetic acid deprotection, so as to obtain the double-end arylamine comb-type polyether. According to the present invention, the epoxy resin is subjected to toughening modification, during the curing process, the active arylamine at the two ends can perform the ring-opening reaction with the epoxy resin so as to achieve the cross-linking curing of the polyether having the comb-type structure and the epoxy resin, and the flexible comb-type polyether chain segment can form the three-dimensional interpenetrating network cross-linking structure with the epoxy resin; the impact strength, the tensile property and the bending property of the epoxy resin are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resins, and specifically to a double-terminal arylamine-based comb-shaped polyether toughened epoxy resin and a preparation method thereof. Background Art

[0002] In recent years, the toughening modification of epoxy resins has been a research hotspot. Traditional toughening agents mainly include polyacrylic acid core-shell particles, carboxyl-terminated nitrile rubber, nanomaterials, etc. Modifying epoxy resins with flexible polyether polymers is a research hotspot. Introducing functional groups such as amino groups and carboxyl groups at the end groups of polyethers can cause curing cross-linking reactions between polyethers and epoxy resins, achieving good toughening effects.

[0003] Reversible addition-fragmentation chain transfer polymerization (RAFT) is a living and controllable free radical polymerization reaction, which can be used to prepare polymers with controllable molecular weights and has broad application prospects in the preparation of block copolymers, graft copolymers, star copolymers, etc. Patent CN113831455B discloses the synthesis of core-shell nanoparticles with styrene-acrylic copolymer as the shell and cross-linked polyacrylate as the core by reversible addition-fragmentation chain transfer free radical (RAFT) polymerization, which are used as additives to toughen epoxy resins. The purpose of the present invention is to prepare a novel double-terminal arylamine-based comb-shaped polyether, which undergoes cross-linking curing with epoxy resins to achieve the toughening modification of epoxy resins. Summary of the Invention

[0004] The technical problem solved by the present invention is: to prepare a double-terminal arylamine-based comb-shaped polyether to achieve the toughening modification of epoxy resins.

[0005] The technical solution provided by the present invention is: A preparation method of a double-terminal arylamine-based comb-shaped polyether toughened epoxy resin, comprising the following steps: S1. Add acrylate polyethylene glycol monomethyl ether and Boc-aminotrithiocarbonate to ethanol and water, add azobisisobutyronitrile under a nitrogen atmosphere, react at a temperature of 60-70 °C for 3-5 h, cool, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-terminal Boc-amino comb-shaped polyether.

[0006] S2. Add trifluoroacetic acid, double-terminal Boc-amino comb-shaped polyether and ethanol co-solvent to dichloromethane, react at room temperature for 3-6 h, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-terminal arylamine-based comb-shaped polyether.

[0007] S3. Add double-terminal arylamine-based comb-shaped polyether to epoxy resin, stir and disperse to obtain a double-terminal arylamine-based comb-shaped polyether toughened epoxy resin.

[0008]

[0009] Further, the masses of Boc-amino trithiocarbonate and azobisisobutyronitrile in S1 are (0.06 - 0.1)% and (0.012 - 0.02)% of poly(ethylene glycol) monomethyl ether acrylate, respectively.

[0010] Further, the volume of ethanol in S1 is 50 - 100% of that of water.

[0011] Further, the mass of trifluoroacetic acid in S2 is 2 - 5% of that of the double-ended Boc-amino comb-shaped polyether.

[0012] Further, the volume of ethanol in S2 is 30 - 60% of that of dichloromethane.

[0013] Further, the mass of the double-ended arylamine-based comb-shaped polyether in S3 is 5 - 30% of that of the epoxy resin.

[0014] Further, the preparation method of the Boc-amino trithiocarbonate includes the following steps: Add S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, carbobenzoxy-4-hydroxyaniline, and p-toluenesulfonic acid to toluene, react at 80 - 100 °C for 6 - 12 h, cool, distill under reduced pressure, and recrystallize the product with dichloromethane to obtain Boc-amino trithiocarbonate.

[0015]

[0016] Further, the masses of carbobenzoxy-4-hydroxyaniline and p-toluenesulfonic acid are (140 - 180)% and (12 - 15)% of that of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, respectively.

[0017] The technical effects of the present invention are as follows: Reacting S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate with carbobenzoxy-4-hydroxyaniline to obtain a novel RAFT reagent, Boc-amino trithiocarbonate. Initiating the polymerization of poly(ethylene glycol) monomethyl ether acrylate through a living and controllable reversible addition-fragmentation chain transfer polymerization reaction, and finally deprotecting with trifluoroacetic acid to obtain a double-ended arylamine-based comb-shaped polyether.

[0018] The present invention uses the double-ended arylamine-based comb-shaped polyether to toughen and modify the epoxy resin. During the curing process, the active arylamines at both ends can undergo a ring-opening reaction with the epoxy resin, realizing the cross-linking and curing of the polyether with a comb-shaped structure and the epoxy resin. Its flexible comb-shaped polyether chain segments can form a three-dimensional interpenetrating network cross-linked structure with the epoxy resin, playing a good toughening role and improving the impact strength, tensile properties, and flexural properties of the epoxy resin. Detailed Embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] 35 mL of triethylamine and 25 g of methoxypolyethylene glycol (average molecular weight 600) were added to 350 mL of toluene. Acryloyl chloride was added dropwise under an ice bath, and then the reaction was carried out at 25 °C for 36 h. After filtration, the filtrate was collected, precipitated with n-hexane, filtered, and dried to obtain methoxypolyethylene glycol acrylate, and the structural formula is 。

[0021] Example 1 50 mg of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, 70 mg of carbonyloxy-4-hydroxyaniline, and 6 mg of p-toluenesulfonic acid were added to 4 mL of toluene. The reaction was carried out at 90 °C for 12 h, cooled, and distilled under reduced pressure. The product was recrystallized from dichloromethane to obtain Boc-amino trithiocarbonate.

[0022] 30 g of methoxypolyethylene glycol acrylate and 18 mg of Boc-amino trithiocarbonate were added to 200 mL of ethanol and 400 mL of water. 3.6 mg of azobisisobutyronitrile was added under a nitrogen atmosphere, and the reaction was carried out at 70 °C for 5 h. After cooling, it was distilled under reduced pressure, washed with n-hexane, and dried to obtain a double-ended Boc-amino comb-shaped polyether.

[0023] 0.5 g of trifluoroacetic acid, 20 g of double-ended Boc-amino comb-shaped polyether, and 100 mL of ethanol cosolvent were added to 200 mL of dichloromethane. The reaction was carried out at room temperature for 3 h, distilled under reduced pressure, washed with n-hexane, and dried to obtain a double-ended aromatic amine-based comb-shaped polyether.

[0024] 5% of the double-ended aromatic amine-based comb-shaped polyether based on the mass of epoxy resin 51 was added to the epoxy resin 51, and stirred and dispersed to obtain a double-ended aromatic amine-based comb-shaped polyether toughened epoxy resin.

[0025] Example 2 50 mg of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, 90 mg of carbonyloxy-4-hydroxyaniline, and 7.5 mg of p-toluenesulfonic acid were added to 2 mL of toluene. The reaction was carried out at 80 °C for 12 h, cooled, and distilled under reduced pressure. The product was recrystallized from dichloromethane to obtain Boc-amino trithiocarbonate.

[0026] Add 30 g of acrylate polyethylene glycol monomethyl ether and 20 mg of Boc-amino trithiocarbonate to 250 mL of ethanol and 400 mL of water. Add 4.2 mg of azobisisobutyronitrile under a nitrogen atmosphere and react at 70 °C for 5 h. Cool, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-ended Boc-amino comb-shaped polyether.

[0027] Add 1 g of trifluoroacetic acid, 20 g of double-ended Boc-amino comb-shaped polyether, and 60 mL of ethanol cosolvent to 200 mL of dichloromethane. React at room temperature for 4 h, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-ended aromatic amine-based comb-shaped polyether.

[0028] Add 10% of the double-ended aromatic amine-based comb-shaped polyether by mass to epoxy resin 51, stir and disperse to obtain a toughened epoxy resin with a double-ended aromatic amine-based comb-shaped polyether.

[0029] Example 3 Add 50 mg of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, 70 mg of carbonyloxy-4-hydroxyaniline, and 6 mg of p-toluenesulfonic acid to 4 mL of toluene. React at 90 °C for 10 h, cool, distill under reduced pressure, and recrystallize the product with dichloromethane to obtain Boc-amino trithiocarbonate.

[0030] Add 30 g of acrylate polyethylene glycol monomethyl ether and 24 mg of Boc-amino trithiocarbonate to 300 mL of ethanol and 400 mL of water. Add 4.5 mg of azobisisobutyronitrile under a nitrogen atmosphere and react at 60 °C for 4 h. Cool, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-ended Boc-amino comb-shaped polyether.

[0031] Add 0.8 g of trifluoroacetic acid, 20 g of double-ended Boc-amino comb-shaped polyether, and 100 mL of ethanol cosolvent to 200 mL of dichloromethane. React at room temperature for 4 h, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-ended aromatic amine-based comb-shaped polyether.

[0032] Add 15% of the double-ended aromatic amine-based comb-shaped polyether by mass to epoxy resin 51, stir and disperse to obtain a toughened epoxy resin with a double-ended aromatic amine-based comb-shaped polyether.

[0033] Example 4 Add 50 mg of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, 90 mg of carbonyloxy-4-hydroxyaniline, and 7.5 mg of p-toluenesulfonic acid to 3 mL of toluene. React at 80 °C for 12 h, cool, distill under reduced pressure, and recrystallize the product with dichloromethane to obtain Boc-amino trithiocarbonate.

[0034] 30 g of acrylate polyethylene glycol monomethyl ether and 26 mg of Boc-aminotrithiocarbonate were added to 300 mL of ethanol and 400 mL of water. 5.5 mg of azobisisobutyronitrile was added under a nitrogen atmosphere, and the reaction was carried out at 65 °C for 4 h. After cooling, distillation under reduced pressure was carried out, followed by washing with n-hexane and drying to obtain a double-ended Boc-amino comb-shaped polyether.

[0035] 1 g of trifluoroacetic acid, 20 g of double-ended Boc-amino comb-shaped polyether and 120 mL of ethanol cosolvent were added to 200 mL of dichloromethane. The reaction was carried out at room temperature for 6 h. After distillation under reduced pressure, washing with n-hexane and drying were carried out to obtain a double-ended aromatic amine-based comb-shaped polyether.

[0036] 22% of the double-ended aromatic amine-based comb-shaped polyether based on the mass of epoxy resin 51 was added to epoxy resin 51, and stirred and dispersed to obtain a double-ended aromatic amine-based comb-shaped polyether toughened epoxy resin.

[0037] Example 5 50 mg of S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, 70 mg of carbonyloxy-4-hydroxyaniline and 6.5 mg of p-toluenesulfonic acid were added to 2 mL of toluene. The reaction was carried out at 80 °C for 12 h. After cooling, distillation under reduced pressure was carried out, and the product was recrystallized from dichloromethane to obtain Boc-aminotrithiocarbonate.

[0038] 30 g of acrylate polyethylene glycol monomethyl ether and 30 mg of Boc-aminotrithiocarbonate were added to 400 mL of ethanol and 400 mL of water. 6 mg of azobisisobutyronitrile was added under a nitrogen atmosphere, and the reaction was carried out at 65 °C for 5 h. After cooling, distillation under reduced pressure was carried out, followed by washing with n-hexane and drying to obtain a double-ended Boc-amino comb-shaped polyether.

[0039] 0.8 g of trifluoroacetic acid, 20 g of double-ended Boc-amino comb-shaped polyether and 80 mL of ethanol cosolvent were added to 200 mL of dichloromethane. The reaction was carried out at room temperature for 3 h. After distillation under reduced pressure, washing with n-hexane and drying were carried out to obtain a double-ended aromatic amine-based comb-shaped polyether.

[0040] 30% of the double-ended aromatic amine-based comb-shaped polyether based on the mass of epoxy resin 51 was added to epoxy resin 51, and stirred and dispersed to obtain a double-ended aromatic amine-based comb-shaped polyether toughened epoxy resin.

[0041] Comparative Example 1 5% of the double-ended Boc-amino comb-shaped polyether based on the mass of epoxy resin 51 was added to epoxy resin 51, and stirred and dispersed to obtain an epoxy resin.

[0042] Comparative Example 2 This comparative example is only epoxy resin 51.

[0043] Triethylenetetramine curing agent was added to the bis(aryl amino)-combed polyether toughened epoxy resin prepared in the examples and the epoxy resin prepared in the comparative example, and its mass was 35% of that of epoxy resin 51. It was poured into a mold, cured at 80 °C for 2 h, then cured at 120 °C for 3 h, and finally cured at 150 °C for 3 h to obtain epoxy resin specimens.

[0044] The impact strength of the epoxy resin specimens was tested according to the method of GB / T1043.1-2008. The tensile properties and flexural properties were tested according to the method of GBT2567-2008.

[0045] The bis(aryl amino)-combed polyether toughened epoxy resin prepared in the examples contains active bis(aryl amino) groups and can participate in the curing reaction of epoxy resin. It is the combed structure of the polyether that undergoes curing crosslinking with the epoxy resin. The combed structure of the polyether can form a three-dimensional interpenetrating network crosslinked structure with the epoxy resin, playing a good toughening role and improving the impact strength, tensile properties and flexural properties of the epoxy resin.

[0046] In Comparative Example 1, bis(Boc-amino)-combed polyether was added, which does not contain active aryl amino groups and cannot undergo curing crosslinking reaction with epoxy resin, resulting in poor toughening effect on epoxy resin.

[0047] Comparative Example 2 is a common epoxy resin with the worst mechanical properties.

[0048] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a double-terminal aromatic amine-based comb-type polyether toughened epoxy resin, characterized in that: The steps include: S1. Add acrylate polyethylene glycol monomethyl ether and Boc-amino trithiocarbonate to ethanol and water, add azobisisobutyronitrile in a nitrogen atmosphere, react at 60-70°C for 3-5 h, cool, distill under reduced pressure, wash with n-hexane, and dry to obtain a double-terminal Boc-amino comb-type polyether; S2, adding trifluoroacetic acid, double-terminated Boc-amino comb-type polyether and ethanol as a cosolvent to dichloromethane, reacting at room temperature for 3-6 h, distilling under reduced pressure, washing with n-hexane, and drying to obtain a double-terminated aromatic amine comb-type polyether; S3, adding double-terminal aromatic amine-based comb-type polyether to the epoxy resin, stirring and dispersing, and obtaining double-terminal aromatic amine-based comb-type polyether toughened epoxy resin.

2. The method for preparing a double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The masses of Boc-aminotrithiocarbonate and azobisisobutyronitrile in S1 are (0.06-0.1)% and (0.012-0.02)% of acrylate polyethylene glycol monomethyl ether, respectively.

3. The method for preparing a double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The volume of ethanol in S1 is 50-100% of water.

4. The method for preparing a double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The mass of trifluoroacetic acid in S2 is 2-5% of the double-terminated Boc-amino comb-type polyether.

5. The method for preparing the double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The volume of ethanol in S2 is 30-60% of dichloromethane.

6. The method for preparing the double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The mass of the double-terminated aromatic amine-based comb-type polyether in S3 is 5-30% of the epoxy resin.

7. The method for preparing a double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 1, characterized in that: The preparation method of the Boc-aminotrithiocarbonate comprises the following steps: Add S,S′-bis(α,α′-dimethyl-α″-acetic acid) trithiocarbonate, oxycarbonyl-4-hydroxyaniline and p-toluenesulfonic acid to toluene, react at 80-100 ℃ for 6-12 h, cool, and distill under reduced pressure. The product is recrystallized from dichloromethane to obtain Boc-amino trithiocarbonate.

8. The method for preparing the double-terminal aromatic amine-based comb-type polyether toughened epoxy resin according to claim 7, characterized in that: The masses of the oxycarbonyl-4-hydroxyaniline and p-toluenesulfonic acid are respectively (140-180)% and (12-15)% of S,S′-di(α,α′-dimethyl-α″-acetic acid) trithiocarbonate.

Images