A thermosetting resin and a method for preparing the same

Abstract

The application discloses a thermosetting resin and a preparation method thereof, and the preparation method comprises the following steps: (1) preparing a prepolymer solution of monomer I and a prepolymer solution of monomer II respectively; the monomer I is a mixture of dicyclopentadiene and ethylidene norbornene; the monomer II is a mixture of dicyclopentadiene and cyclooctene; (2) under a heating condition, preparing a laminated material formed by pre-curing the prepolymer solution of the monomer I and the prepolymer solution of the monomer II; and (3) performing heat treatment on the laminated material obtained in the step (2) to obtain the thermosetting resin. The application is based on a soft and hard combined multi-layer strategy to construct a layered thermosetting resin material with rigidity and toughness, the thermosetting resin provided by the application contains dynamic carbon-carbon double bonds between layers, and the interface effect is enhanced by using chemical bond dynamic exchange and physical swelling behavior, so that the thermosetting resin is efficiently toughened.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of resin materials, in particular to a thermosetting resin and a preparation method thereof. BACKGROUND

[0002] Thermosetting materials and elastomers are two representative functional materials. The former has high crosslinking density, high glass transition temperature, high modulus and high strength, and is often used as transportation and building materials. However, the macroscopic deformation ability of thermosetting materials is poor, and they lack impact resistance, which seriously limits their service life and is not conducive to industrial manufacturing. Elastomers usually exhibit low glass transition temperature and low modulus, and when subjected to external force, the movement of molecular chains provides better anti-deformation ability, and are widely used in wearable devices, shock-absorbing materials and other fields. How to balance the rigidity and flexibility of materials and construct a thermosetting material with high strength and high toughness structure is not only an important cornerstone for promoting the development of aerospace, transportation facilities, national defense and other fields, but also a frontier hotspot for the cross-research of chemistry, mechanics and materials science. SUMMARY

[0003] In view of the above technical problems, the present application aims to provide a thermosetting resin and a preparation method thereof. The present application realizes the combination of rigidity and toughness of the material based on the soft and hard combined multilayer strategy, and enhances the interfacial action by using chemical bond dynamic exchange and physical swelling behavior to realize the efficient toughening of the thermosetting resin.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0005] On the one hand, the present application provides a preparation method of a thermosetting resin, comprising the following steps:

[0006] (1) preparing a prepolymer solution of monomer I and a prepolymer solution of monomer II, respectively; the monomer I is a mixture of dicyclopentadiene and ethylidene norbornene; the monomer II is a mixture of dicyclopentadiene and cyclooctene;

[0007] (2) under heating conditions, preparing a laminated material formed by pre-solidification of the prepolymer solution of monomer I and the prepolymer solution of monomer II;

[0008] (3) heat treating the laminated material obtained in step (2) to obtain a thermosetting resin.

[0009] In the technical scheme of the present application, the laminated material is a laminated material in which the prepolymer solution of monomer I and the prepolymer solution of monomer II are pre-solidified and then overlapped in single layer or overlapped in multiple layers alternately.

[0010] As a preferred embodiment, in step (1), the prepolymer solution of monomer I is obtained by polymerization of monomer I under the action of a catalyst;

[0011] Preferably, the catalyst is at least one selected from Grubbs second generation catalyst, Grubbs third generation catalyst, MgBr2 / TiCl4 and KiRuCl3-H2O;

[0012] Preferably, in the monomer I, the molar ratio of dicyclopentadiene and ethylidene norbornene is 1:0.05-1;

[0013] Preferably, the mass of the catalyst is 0.1%-1% of the total mass of the monomer I, more preferably 0.5%;

[0014] Preferably, the reaction temperature of the polymerization is 30-50°C;

[0015] Preferably, the reaction time of the polymerization is 5-10 min;

[0016] Preferably, the polymerization is carried out under stirring;

[0017] In some specific embodiments, the catalyst is added to the reaction system in the form of being dissolved in a trace amount of organic solvent which volatilizes in the subsequent pre-curing process to form the laminated material.

[0018] As a preferred embodiment, in step (1), the prepolymer solution of the monomer II is obtained by polymerization of the monomer II under the action of the catalyst;

[0019] Preferably, the catalyst is at least one selected from Grubbs second generation catalyst, Grubbs third generation catalyst, MgBr2 / TiCl4 and KiRuCl3-H2O;

[0020] Preferably, in the monomer II, the molar ratio of dicyclopentadiene and cyclooctene is 1:0.25-1, more preferably 1:0.25-0.8;

[0021] Preferably, the mass of the catalyst is 0.1%-1% of the total mass of the monomer II, more preferably 0.5%;

[0022] Preferably, the reaction temperature of the polymerization is 30-50°C;

[0023] Preferably, the reaction time of the polymerization is 5-20 min;

[0024] Preferably, the polymerization is carried out under stirring;

[0025] In some specific embodiments, the catalyst is added to the reaction system in the form of being dissolved in a trace amount of organic solvent which volatilizes in the subsequent pre-curing process to form the laminated material.

[0026] As a preferred embodiment, in step (2), the heating temperature is 30-50℃, and the heating time is 5-20min.

[0027] Preferably, the preparation process of the layered material is: ① coating or alternatively coating the prepolymer solution of monomer I and the prepolymer solution of monomer II on the substrate in turn under heating condition to obtain a layered material; or, ② injecting the prepolymer solution of monomer I and the prepolymer solution of monomer II into a mold in turn or alternatively in turn under heating condition to obtain a layered material.

[0028] Preferably, the coating is blade coating.

[0029] Preferably, in the coating or alternatively coating in turn, the coating mass ratio of the prepolymer solution of monomer I and the prepolymer solution of monomer II is 2-3:3-4.

[0030] Preferably, in the injection or alternatively injection in turn, the injection mass ratio of the prepolymer solution of monomer I and the prepolymer solution of monomer II is 2-3:3-4.

[0031] In the technical solution of the present application, the layered material with low crosslinking density can be obtained by pre-solidification under heating condition.

[0032] As a preferred embodiment, in step (3), the heat treatment condition is: temperature 80-120℃, time 1-6h.

[0033] Preferably, the heat treatment is heating at 100℃ for 3h.

[0034] In the technical solution of the present application, further heat treatment can improve the crosslinking density of the material, thereby realizing the toughening effect.

[0035] In another aspect, the present application provides a thermosetting resin obtained by the above preparation method.

[0036] The present application has the following advantages:

[0037] The present application is based on the soft and hard combined multi-layer strategy to construct a thermosetting resin material with rigidity and toughness. First, a low crosslinking density multi-layer material is prepared by coating or alternatively coating the prepolymer solution of hard layer monomer / soft layer monomer in turn or injecting the prepolymer solution of hard layer monomer / soft layer monomer into a mold respectively, and finally a high toughness and strong impact resistance multi-layer toughened thermosetting resin is obtained by improving the crosslinking density through heat treatment. The hard layer is the polymerization product of monomer I (dicyclopentadiene and ethylidene norbornene), and the soft layer is the polymerization product of monomer II (dicyclopentadiene and cyclooctene).

[0038] Compared with the prior art, the present application has the following advantages:

[0039] 1. The reaction raw material adopted by the present application is easy to obtain and has low viscosity, the preparation process is simple, the polymerization gelation time is short, the forming processing speed is fast, and the cost is low;

[0040] 2. The thermosetting resin provided by the present application contains dynamic carbon-carbon double bonds between layers, and the interface effect is enhanced by dynamic exchange of chemical bonds and physical swelling behavior, so that the thermosetting resin is efficiently toughened;

[0041] 3. The thermosetting resin provided by the present application has excellent mechanical properties, mainly showing high rigidity and toughness, and excellent impact resistance. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a stress-strain curve of the thermosetting resin in Example 1 of the present application;

[0043] Figure 2 is a sample piece diagram of the thermosetting resin in Example 1 of the present application;

[0044] Figure 3 is a scanning electron microscope image of the thermosetting resin in Example 1 of the present application;

[0045] Figure 4 is a ballistic penetration diagram of the thermosetting resin in Example 2 of the present application;

[0046] Figure 5 is a thermogravimetric analysis curve of the thermosetting resin in Example 3 of the present application. DETAILED DESCRIPTION

[0047] The following examples are only a part of the embodiments of the present application, not all the embodiments. Therefore, the detailed description of the following provided embodiments of the present application is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0048] In the present application, unless specified, all equipment and raw materials, etc. can be purchased from the market or commonly used in the industry. The methods in the following examples, unless otherwise specified, are conventional methods in the art.

[0049] Example 1:

[0050] The thermosetting resin in this embodiment is obtained by the following preparation method:

[0051] 7.8g dicyclopentadiene, 0.4g ethylidene norbornene, 10mg catalyst (Grubbs second generation catalyst, dissolved in a small amount of dichloromethane) were stirred at 30℃ for 0.16h to prepare a hard layer prepolymer solution;

[0052] A soft layer prepolymer solution was prepared by stirring 5.4 g of dicyclopentadiene, 1.9 g of cyclooctene, and 10 mg of catalyst (Grubbs second-generation catalyst dissolved in a small amount of dichloromethane) at 30 °C for 0.16 h;

[0053] A PET film was placed on a hot stage, and after being heated to 40 °C, the soft / hard layer prepolymer solutions were alternately and repeatedly coated. The mass ratio of a single soft / hard layer prepolymer coating was 2:3. After being heated for 0.3 h for pre-curing, a low-crosslinking degree layered material was obtained (after pre-curing, the thickness of the single hard layer structure and the single soft layer structure was 200 μm).

[0054] The low-crosslinking degree layered material was heat treated in an oven at 100 °C for 3 h to obtain a thermoset resin.

[0055] The thermoset resin prepared in this example was cut into dumbbell-shaped samples (50 mm in gauge length, 10 mm in width, and 4 mm in thickness). The stress-strain curve of the tensile test of the sample was obtained according to GB / T 2567-2021 Resin Cast Performance Test Method, as shown in Figure 1 . The tensile strength was measured to be 46.5 MPa, and the elongation at break was 240%, proving that the material has excellent mechanical strength. The picture and scanning electron microscope image of the thermoset resin sample prepared in this example are shown in Figure 2 and Figure 3 .

[0056] Example 2:

[0057] The thermoset resin in this example was prepared by the following preparation method:

[0058] A hard layer prepolymer solution was prepared by stirring 15.6 g of dicyclopentadiene, 0.8 g of ethylidene norbornene, and 20 mg of catalyst (Grubbs second-generation catalyst dissolved in a small amount of dichloromethane) at 30 °C for 0.16 h.

[0059] A soft layer prepolymer solution was prepared by stirring 10.8 g of dicyclopentadiene, 3.8 g of cyclooctene, and 20 mg of catalyst (Grubbs second-generation catalyst dissolved in a small amount of dichloromethane) at 30 °C for 0.16 h.

[0060] The soft / hard layer prepolymer solutions were sequentially poured into a mold, and pre-curing was performed at 40 °C for 0.3 h to obtain a low-crosslinking degree layered material.

[0061] The low-crosslinking degree layered material was heat treated in an oven at 100 °C for 3 h to obtain a thermoset resin with a thickness of 12 mm.

[0062] The thermoset resin material prepared in this example was subjected to a ballistic penetration experiment using a Lugur rifle at a distance of 10 meters, as shown in Figure 4As shown, it is proved that the material has excellent impact resistance.

[0063] Example 3:

[0064] The thermosetting resin in this example is prepared by the following method:

[0065] 7.8 g of dicyclopentadiene, 0.4 g of ethylidene norbornene, 10 mg of catalyst (Grubbs second-generation catalyst dissolved in a small amount of dichloromethane) are stirred at 30℃ for 0.16h to prepare a hard layer prepolymer solution;

[0066] 5.4 g of dicyclopentadiene, 1.9 g of cyclooctene, 10 mg of catalyst (Grubbs second-generation catalyst dissolved in a small amount of dichloromethane) are stirred at 30℃ for 0.16h to prepare a soft layer prepolymer solution;

[0067] Place the PET film on the hot stage, heat to 40℃, and alternately coat the soft and hard layer prepolymer solutions, with a single soft / hard layer prepolymer solution coating mass ratio of 2:3; heat for 0.3h to pre-cure to obtain a low crosslinking degree layered material;

[0068] The low crosslinking degree layered material is further heat treated in an oven at 100℃ for 3h to further improve the crosslinking density, and finally obtain the thermosetting resin.

[0069] The thermosetting resin prepared in this example is subjected to thermogravimetric test, as shown in Figure 5 The mass loss of the multilayer resin at 400℃ is only 3.6%, which proves that the material has excellent heat resistance.

[0070] The above is only a preferred embodiment of the present application, it should be noted that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for producing a thermosetting resin, characterized by, The method comprises the following steps: (1) preparing a pre-polymer solution of monomer I and a pre-polymer solution of monomer II respectively; the monomer I is a mixture of dicyclopentadiene and ethylidene norbornene; the monomer II is a mixture of dicyclopentadiene and cyclooctene; (2) preparing a laminated material by pre-curing the pre-polymer solution of monomer I and the pre-polymer solution of monomer II under heating; (3) heat treating the laminated material obtained in step (2) to obtain a thermosetting resin; The laminated material is prepared by: ① coating or alternatively coating the pre-polymer solution of monomer I and the pre-polymer solution of monomer II on a substrate under heating to obtain a laminated material; or ② injecting or alternatively injecting the pre-polymer solution of monomer I and the pre-polymer solution of monomer II into a mold under heating to obtain a laminated material; In the monomer I, the molar ratio of dicyclopentadiene to ethylidene norbornene is 1:0.05-1; In the monomer II, the molar ratio of dicyclopentadiene to cyclooctene is 1:0.25-1; In the coating or alternatively coating, the mass ratio of the pre-polymer solution of monomer I to the pre-polymer solution of monomer II is 2-3:3-4; In the injection or alternatively injection, the mass ratio of the pre-polymer solution of monomer I to the pre-polymer solution of monomer II is 2-3:3-4.

2. The production method according to claim 1, characterized by, In step (1), the pre-polymer solution of monomer I is obtained by polymerization of monomer I under the action of a catalyst.

3. The method of claim 2, wherein, The catalyst is at least one selected from Grubbs second-generation catalyst, Grubbs third-generation catalyst, MgBr2 / TiCl4 and KiRuCl3·H2O.

4. The preparation method according to claim 2, characterized in that, The mass of the catalyst is 0.1%-1% of the total mass of monomer I.

5. The preparation method according to claim 4, characterized in that, The mass of the catalyst is 0.5% of the total mass of monomer I.

6. The preparation method according to claim 2, characterized in that, The reaction temperature of the polymerization is 30-50℃.

7. The preparation method according to claim 2, characterized in that, The reaction time of the polymerization is 5-10 min.

8. The preparation method according to claim 2, characterized in that, The polymerization is carried out under stirring.

9. The method of claim 1, wherein, In step (1), the pre-polymer solution of monomer II is obtained by polymerization of monomer II under the action of a catalyst.

10. The method of claim 9, wherein, The catalyst is at least one selected from Grubbs second-generation catalyst, Grubbs third-generation catalyst, MgBr2 / TiCl4 and KiRuCl3·H2O.

11. The method of claim 1, wherein, In the monomer II, the molar ratio of dicyclopentadiene to cyclooctene is 1:0.25-0.

8.

12. The method of claim 9, wherein, The mass of the catalyst is 0.1%-1% of the total mass of monomer II.

13. The method of claim 12, wherein, The mass of the catalyst is 0.5% of the total mass of monomer II.

14. The method of claim 9, wherein, The reaction temperature of the polymerization is 30-50℃.

15. The preparation method according to claim 9, characterized in that, The reaction time of the polymerization is 5-20 min.

16. The method of claim 9, wherein, The polymerization is carried out under stirring.

17. The method of claim 1, wherein, In step (2), the heating temperature is 30-50℃, and the heating time is 5-20 min.

18. The method of claim 1, wherein, The coating is doctor blading.

19. The method of claim 1, wherein, In step (3), the heat treatment is carried out at a temperature of 80-120℃ for 1-6 h.

20. The method of claim 1, wherein, In step (3), the heat treatment is carried out at 100℃ for 3 h.

21. The thermosetting resin obtained by the method of any one of claims 1-20.

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