Polysiloxane block polyoxyethylene ether hyperbranched amine as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of epoxy toughening agents, and relates to polysiloxane block polyoxyethylene ether hyperbranched amine as well as a preparation method and application thereof. Epoxy-terminated siloxane block polyvinyl ether is prepared through a hydrosilylation reaction, the epoxy-terminated siloxane block polyvinyl ether reacts with organic polyamine, a flexible Si-O-Si chain segment and a polar polyoxyethylene EO chain segment are introduced, siloxane block polyoxyethylene ether hyperbranched amine with high reaction activity and low viscosity is obtained through a hyperbranched reaction, an alkali chain extension technology is applied, and the high-reactivity low-viscosity hyperbranched siloxane block polyvinyl ether is obtained. A Si-O-Si chain link is prolonged, and the polysiloxane block polyoxyethylene ether hyperbranched amine is prepared. The (poly) siloxane block polyvinyl ether hyperbranched amine is applied to epoxy resin as a flexibilizer, after amino and an epoxy system are subjected to a cross-linking reaction, the impact resistance (toughness is enhanced) of an epoxy resin material can be remarkably improved, the thermal stability and the weather resistance are improved, and compared with a common flexibilizer, the (poly) siloxane block polyvinyl ether hyperbranched amine has the advantages that the impact resistance is greatly improved; the influence on the tensile strength and the bending strength of the material is small.

Description

Technical Field

[0001] The present invention belongs to the technical field of epoxy toughening agents, and relates to a polysiloxane-block-polyoxyethylene ether hyperbranched amine, a preparation method thereof, and an application thereof. Background Art

[0002] Carbon fiber reinforced epoxy resin composites have the characteristics of light weight, high specific strength and high specific modulus, and are widely used in industries such as automotive parts, building materials, and aerospace. After curing, pure epoxy resin has disadvantages such as high crosslinking degree, high internal stress, and large brittleness, which limits the application of composites in fields with high performance requirements. To improve the comprehensive performance of composites, the matrix material can be started with, and the epoxy resin system can be toughened and modified. The delamination damage of carbon fiber reinforced epoxy resin matrix composites after low-velocity impact is also due to the insufficient toughness of the epoxy resin itself.

[0003] Common toughening methods for epoxy resin include physical toughening and chemical modification toughening. Among them, chemical modification forms an interpenetrating network through special structure polymers such as block copolymers and hyperbranched polymers with epoxy resin, and then introduces flexible chain segments to establish a three-dimensional network of "soft-hard" alternation, which can greatly increase the absorption of energy and achieve the purpose of toughening. The present invention introduces flexible siloxane chain segments and polar ethoxy blocks to synthesize polysiloxane-block-polyoxyethylene ether hyperbranched amine; the active amino groups at the ends of the hyperbranched compounds can improve the reaction activity and compatibility with epoxy resin, and the presence of flexible chain segments can enhance the impact strength of the epoxy cured product. Summary of the Invention

[0004] The present invention provides a polysiloxane-block-polyoxyethylene ether hyperbranched amine, a preparation method thereof, and an application thereof. When the polysiloxane-block-polyoxyethylene ether hyperbranched amine is added to epoxy resin, it has the effect of toughening and modifying.

[0005] In the first aspect of the present invention, a preparation method of a siloxane-block-polyoxyethylene ether hyperbranched amine is provided, and the preparation method includes the following steps:

[0006] S1. Under the protection of N2, add a chloroplatinic acid / isopropanol dispersion liquid to allyl polyoxyethylene epoxy ether, heat up to 50-100 °C, and then uniformly dropwise add 1,1,3,3-tetramethyldisiloxane. After reacting for 2-8 h, a terminal epoxy group siloxane-block-polyoxyethylene ether is prepared;

[0007] S2. React the terminal epoxy group siloxane-block-polyoxyethylene ether with an organic polyamine at 30-90 °C for 4-8 h to obtain a siloxane-block-polyoxyethylene ether hyperbranched amine.

[0008] In some embodiments of the present invention, in step S1 of the above preparation method, the concentration of chloroplatinic acid / isopropanol dispersion is 0.8 - 2.5 wt%, and the mass ratio of chloroplatinic acid / isopropanol dispersion, allyl polyoxyethylene epoxy ether to 1,1,3,3 - tetramethyldisiloxane is (0.7 - 1.4) : (300 - 600) : (50 - 100).

[0009] In some embodiments of the present invention, in step S2 of the above preparation method, the organic polyamine is diethylenetriamine or triethylenetetramine, and the mass ratio of the terminal epoxy group - containing siloxane block polyoxyethylene ether to the organic polyamine is (180 - 500) : (40 - 100).

[0010] In the second aspect of the present invention, there is provided a siloxane - block polyoxyethylene - based hyperbranched amine prepared by the above - mentioned preparation method.

[0011] In the third aspect of the present invention, there is provided a method for preparing a polysiloxane - block polyoxyethylene - based hyperbranched amine. The preparation method is as follows: Under the protection of N2, a chain extender and a catalyst are added to the siloxane - block polyethylene - based hyperbranched amine, and a chain - extension reaction is carried out at 110 - 160 °C to obtain the polysiloxane - block polyoxyethylene - based hyperbranched amine; the siloxane - block polyethylene - based hyperbranched amine is the above - mentioned siloxane - block polyethylene - based hyperbranched amine.

[0012] The synthetic route of the above preparation method is as Figure 3 shown.

[0013] In some embodiments of the present invention, in the preparation method of the polysiloxane - block polyoxyethylene - based hyperbranched amine, the mass ratio of the siloxane - block polyethylene - based hyperbranched amine, the chain extender and the catalyst is (200 - 400) : (40 - 80) : (6 - 12).

[0014] In the fourth aspect of the present invention, there is provided a polysiloxane - block polyoxyethylene - based hyperbranched amine prepared by the above - mentioned preparation method.

[0015] In the fifth aspect of the present invention, there is provided an application of the above - mentioned siloxane - block polyoxyethylene - based hyperbranched amine or the above - mentioned polysiloxane - block polyoxyethylene - based hyperbranched amine as a toughening agent in epoxy resin materials.

[0016] In the sixth aspect of the present invention, an epoxy resin composite material is provided. The epoxy resin composite material is obtained by curing a mixture of an epoxy resin, a curing agent, and a toughening agent. The toughening agent is the above-mentioned siloxane-block polyoxyethylene-based ether hyperbranched amine or the above-mentioned polysiloxane-block polyoxyethylene-based ether hyperbranched amine. The curing conditions are preferably: curing at 80 - 90 °C for 20 - 40 min, and then raising the temperature to 100 - 110 °C and curing for 1 - 1.5 h. Preferably, epoxy E-51 is selected as the epoxy resin, and A-50 is selected as the curing agent; or, epoxy TDE-85 is selected as the epoxy resin, and 4,4'-diaminodiphenyl sulfone is selected as the curing agent.

[0017] In the seventh aspect of the present invention, a carbon fiber reinforced epoxy resin composite material is provided. The carbon fiber reinforced epoxy resin composite material is obtained by curing a mixture of an epoxy resin, a curing agent, and a toughening agent after infiltrating carbon fibers by a vacuum-assisted method. The toughening agent is the above-mentioned siloxane-block polyoxyethylene-based ether hyperbranched amine or the above-mentioned polysiloxane-block polyoxyethylene-based ether hyperbranched amine. The curing conditions are preferably: curing at 60 - 90 °C for 1 - 3 h, or curing at 50 - 100 °C for 1 - 2 h and then curing at 110 - 130 °C for 2 - 3 h.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) In this application, a terminal epoxy group-containing siloxane-block polyethylene ether is prepared through a hydrosilylation reaction, and reacted with an organic polyamine to introduce flexible Si-O-Si chain segments and polar polyoxyethylene EO chain segments. Through a hyperbranched reaction, a siloxane-block polyoxyethylene-based ether hyperbranched amine with high reactivity and low viscosity is formed, and an alkali chain extension technology is used to extend the Si-O-Si link to prepare a polysiloxane-block polyoxyethylene-based ether hyperbranched amine. When the siloxane-block polyethylene ether hyperbranched amine or the polysiloxane-block polyoxyethylene-based ether hyperbranched amine is used as a toughening agent in an epoxy resin, after cross-linking reaction occurs between the amino group and the epoxy system, the impact resistance of the epoxy resin material can be significantly improved (toughness enhanced), the thermal stability and weather resistance can be increased, and compared with general toughening agents, the influence on the tensile strength and flexural strength of the material is relatively small.

[0020] (2) The polysiloxane-block polyoxyethylene ether hyperbranched amine prepared in this application forms a special branched structure due to the steric hindrance between its molecules, and at the same time contains a large number of active amino groups at the ends. There are a large number of cavities between the molecules of the hyperbranched structure, which reduces the chain segment entanglement and increases the free volume of the resin, thereby being able to reduce the viscosity and being beneficial to plastic deformation to improve toughness. Moreover, the high reactivity of the hyperbranched structure improves the compatibility between the toughening agent and the epoxy resin.

[0021] (3) The toughener provided by this application contains block polar polyoxyethylene (EO) segments and is applied to the preparation of carbon fiber reinforced epoxy resin composites. It can enhance the interfacial properties between the resin and the carbon fiber, thereby improving the tensile strength, flexural strength, and shear strength of the carbon fiber reinforced epoxy resin composites. Description of the Drawings

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them,

[0023] Figure 1 is the microscopic morphology after the impact failure of the epoxy cured products (Sample 1 and Sample 3) provided by the embodiments of the present invention;

[0024] Figure 2 is the surface morphology diagram of the carbon fiber reinforced epoxy resin composites (Sample 2 and Sample 4) after tensile failure provided by the embodiments of the present invention;

[0025] Figure 3 is the synthesis route diagram of the polysiloxane block polyoxyethylene ether hyperbranched amine provided by the embodiments of the present invention. Detailed Embodiments

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, rather than all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0027] In order to solve the problem of insufficient toughness of carbon fiber / epoxy resin composites, the present invention prepares terminal epoxy group polysiloxane block polyvinyl ether by hydrosilylation, and then reacts with organic polyamine to obtain a polysiloxane block polyoxyethylene ether hyperbranched amine toughener, which can reduce the internal stress of the resin and improve the toughness. At the same time, the hyperbranched amine has characteristics such as low viscosity and high reactivity. After being blended with epoxy resin, it is beneficial for the matrix to infiltrate the carbon fiber and improve the mechanical properties of the composite material.

[0028] The materials used in the embodiments of the present invention are commercially available products, and the product information is as follows:

[0029] The organic polyamines in the experimental raw materials include diethylenetriamine and triethylenetetramine; the mass ratio of the epoxy E-51 system is 100:25 (E-51 from BlueStar New Materials Wuxi Resin Factory and modified amine curing agent A-50 from Huai'an Xinghuai Curing Chemical Research Institute); the mass ratio of the epoxy TDE-85 system is 100:50 (TDE-85 4,5-epoxyhexane-1,2-dicarboxylic acid diglycidyl ester and curing agent 4,4'-diaminodiphenyl sulfone (DDS) from Tianjin Jindong Chemical Factory, and from Shanghai Reagent Factory No. 3), and carbon fiber T300 plain woven fabric (from Jiangyin Tianji New Materials Technology Co., Ltd.).

[0030] Example 1

[0031] Step 1: Prepare terminal epoxy group siloxane-block polyoxyethylene ether 1 (modified silicone oil 1)

[0032] Under the condition of introducing N2, add 450 g of allyl epoxy polyether into a four-necked flask. After heating to 70 °C, add 0.7 g of chloroplatinic acid / isopropanol dispersion (1.5 wt%) as a catalyst, and then dropwise add 50 g of 1,1,3,3-tetramethyldisiloxane and react for 6 h. After cooling to room temperature, remove impurities by rotary evaporation at 80 °C to obtain terminal epoxy group siloxane-block polyoxyethylene ether 1 (modified silicone oil 1).

[0033] Step 2: Prepare siloxane-block polyvinyl ether hyperbranched amine 1

[0034] Add 50 g of diethylenetriamine into a four-necked flask at room temperature, and slowly dropwise add 500 g of the synthesized modified silicone oil 1, then heat up to 80 °C and react for 8 h to prepare siloxane-block polyvinyl ether hyperbranched amine 1 (HBP1).

[0035] Example 2

[0036] Step 1: Prepare terminal epoxy group siloxane-block polyoxyethylene ether 2 (modified silicone oil 2)

[0037] Under the protection of N2, dropwise add 50 g of 1,1,3,3-tetramethyldisiloxane into a four-necked flask containing 300 g of allyl polyoxyethylene epoxy ether and 0.4 g of chloroplatinic acid / isopropanol dispersion (0.8 wt%), and then react at 90 °C for 8 h. Rotary evaporate at 90 °C until constant weight to obtain terminal epoxy group siloxane-block polyvinyl ether 2 (modified silicone oil 2).

[0038] Step 2: Prepare siloxane-block polyvinyl ether hyperbranched amine 2

[0039] Add 70 g of triethylenetetramine into another four-necked flask at room temperature, slowly dropwise add 350 g of the synthesized modified silicone oil 2, heat up to 90 °C and react for 7 h to prepare siloxane-block polyvinyl ether hyperbranched amine 2 (HBP2).

[0040] Step 3: Synthesis of polysiloxane-block-polyvinyl ether hyperbranched amine

[0041] Under N2 protection, 200 g of the above-prepared siloxane-block-polyvinyl ether hyperbranched amine 2 and 40 g of D4 chain extender were uniformly mixed, and a chain extension reaction was carried out at 130 °C with 6 g of KOH as a catalyst for 7 h to obtain polysiloxane-block-polyvinyl ether hyperbranched amine (HBP3).

[0042] Example 3

[0043] 500 g of epoxy TDE-85 / DDS system (w:w = 100:45) and 50 g of siloxane-block-polyvinyl ether hyperbranched amine 1 (HBP1) were uniformly mixed and degassed under vacuum for 10 min.

[0044] A part of the resin mixture after vacuum degassing (~150 g) was poured into a silica gel mold, cured at 80 °C for 30 min, then heated to 110 °C and cured for 1 h, and left overnight to prepare a toughened TDE-85 / DDS cured product (Sample 1). The preparation process (temperature and time) of the TDE-85 / DDS cured product was the same as that of Sample 1, but due to no addition of HBP1, the mass ratio of TDE-85 to DDS was 100:50.

[0045] Another part of the resin mixture (~350 g) was infiltrated into 10 layers of carbon fiber woven fabric (25 cm × 25 cm, with the laying angle alternating between 0° / 90°) by vacuum-assisted molding method, cured at 0.2 MPa and 80 °C for 2 h, then cured at 120 °C for 3 h, and left at room temperature for 2 - 3 days to obtain a carbon fiber-reinforced epoxy resin composite (Sample 2). The preparation process of the TDE-85 / DDS curing system / carbon fiber composite system (carbon fiber laying method, temperature, time, pressure and post-curing placement time) was the same as that of Sample 2. Due to no addition of HBP1, the mass ratio of TDE-85 to DDS was 100:50.

[0046] Example 4

[0047] 600 g of E-51 / A-50 epoxy resin system (mass ratio 100:21) and 48 g of polysiloxane-block-polyvinyl ether hyperbranched amine (HBP3) were stirred evenly and then degassed under vacuum for 15 min.

[0048] A part (~150 g) was poured into a silica gel mold to prepare a toughened epoxy cured product E-51 / A-50, cured at 90 °C for 2 h, and left overnight (Sample 3). The preparation method of the E-51 / A-50 cured product was the same as that of Sample 3. Due to no addition of HBP3, the mass ratio of E-51 to A-50 was 100:25.

[0049] Another part of the resin mixture (~450 g) was infiltrated with 15 layers of carbon fiber woven fabric (25 cm × 25 cm, with the laying angles alternating between 0° and 90°) using the vacuum-assisted resin infusion method. After curing at 0.15 MPa and 90 °C for 2 h, it was left at room temperature for 2 - 3 days to obtain a carbon fiber-reinforced epoxy composite material (Sample 4). The preparation process of the E-51 / A-50 curing system / carbon fiber composite material system was the same as that of Sample 4, without adding HBP3, and the mass ratio of E-51 to A-50 was 100:25.

[0050] Test Example 1: Testing the mechanical properties of the epoxy cured product

[0051] Referring to GB / T 2570-2021

[76] , using a 5969H type Instron universal material testing machine, the tensile strength and flexural strength of the epoxy cured product were measured respectively: the tensile specimen was dumbbell-shaped, with the specimen size of 200 mm × 20 mm × 4 mm, and each upper and lower chuck clamped 40 mm, and the tensile rate was 10 mm / min; the flexural specimen was rectangular, with the standard size of 150 mm × 15 mm × 10 mm (l × h × b), the span was 16 times the thickness (h), and the rate was 2 mm / min.

[0052] Referring to GB / T1843-2008

[77] , the impact strength of the epoxy cured product was measured using a Zbc8501-A pendulum impact testing machine. The specimen was rectangular, 80 mm × 10 mm × 4 mm, and the pendulum energy was 22 J. The microscopic morphology after impact failure is as Figure 1 shown. The left figure is the morphology diagram of Sample 1 after impact failure, and the right figure is the morphology diagram of Sample 2 after impact failure.

[0053] The test results of the mechanical properties such as the tensile, flexural, and impact strengths of Sample 1 and Sample 3 provided by the present invention are shown in Table 1.

[0054] As can be seen from Table 1 and Figure 1 it can be known that, compared with the original epoxy cured product system, using the hyperbranched polymer as a toughening agent has little effect on the tensile and flexural strengths of the cured product, but can significantly improve the impact strength (≥200%). The prepared hyperbranched polymer has abundant terminal amino groups, which can enhance its compatibility with epoxy resin. The flexibility of the (poly)siloxysilane and polar ethoxy chain segments and the special cavity structure of the hyperbranched polymer can effectively achieve the plastic deformation of the epoxy cured product system when subjected to impact force, enhancing its toughness.

[0055] Test Example 2: Testing the mechanical properties of the carbon fiber / toughened epoxy composite material

[0056] Referring to the test method for tensile properties of fiber - reinforced plastics in GB / T 1447 - 2005

[80] , the tensile strength of carbon fiber - reinforced epoxy composites was tested using a 5969H type Instron universal material testing machine. Figure 2 It is the surface morphology diagram of the specimen after tensile failure of carbon fiber - reinforced epoxy resin composites (the left figure is sample 2 and the right figure is sample 4).

[0057] Referring to the test method for flexural properties of fiber - reinforced plastics in GB / T 1449 - 2005

[81] , the flexural strength of carbon fiber - reinforced epoxy composites was tested using a 5969H type Instron universal material testing machine.

[0058] Referring to the test method for short - beam shear strength of polymer - matrix composites in GB / T 30969 - 2014

[82] , the shear strength of carbon fiber - reinforced epoxy composites was tested using a 5982 type Instron universal material testing machine.

[0059] The tensile strength, flexural strength and shear strength of carbon fiber / toughened epoxy composites are shown in Table 2. From Table 2 and Figure 2 it can be seen that there are few entanglements and low viscosity between the molecular chain segments of the toughened hyperbranched amine structure. After being mixed with epoxy and curing agent, it still maintains a low viscosity, which is beneficial to the infiltration of resin into carbon fiber during the vacuum - assisted molding process; while the block polar polyoxyethylene (EO) chain segments enhance the interfacial properties between the resin and carbon fiber, realizing the improvement of the tensile, flexural and shear properties of the composites.

[0060] Table 1 Mechanical properties of toughened epoxy cured system

[0061]

[0062] Table 2 Mechanical properties of carbon fiber - reinforced epoxy composites

[0063]

[0064] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the relevant technical field can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing a siloxane-block polyoxyethylene ether hyperbranched amine, characterized in that: The preparation method comprises the following steps: S1. Under N2 protection conditions, add chloroplatinic acid / isopropanol dispersion to allyl polyoxyethylene epoxy ether, heat to 50-100°C, then uniformly add 1,1,3,3-tetramethyldisiloxane dropwise, react for 2-8h, and obtain terminal epoxysiloxane block polyoxyethylene ether; S2. reacting the epoxy-terminated siloxane block polyoxyethylene ether with an organic polyamine at 30-90° C. for 4-8 hours to obtain a siloxane block polyoxyethylene ether hyperbranched amine.

2. The preparation method according to claim 1, characterized in that: In step S1, the concentration of the chloroplatinic acid / isopropanol dispersion is 0.8-2.5wt%, and the mass ratio of the chloroplatinic acid / isopropanol dispersion, allyl polyoxyethylene epoxy ether and 1,1,3,3-tetramethyldisiloxane is (0.7-1.4):(300-600):(50-100).

3. The preparation method according to claim 1, characterized in that: In step S2, the organic polyamine is diethylenetriamine or triethylenetetramine, and the mass ratio of the terminal epoxysiloxane block polyoxyethylene ether to the organic polyamine is (180-500): (40-100).

4. The siloxane block polyoxyethylene ether hyperbranched amine prepared by the preparation method according to any one of claims 1 to 3.

5. A method for preparing a polysiloxane block polyoxyethylene ether hyperbranched amine, characterized in that: The preparation method comprises: adding a chain extender and a catalyst to a siloxane block polyvinyl ether hyperbranched amine under N2 protection conditions, and carrying out a chain extension reaction at 110-160° C. to obtain a polysiloxane block polyoxyethylene ether hyperbranched amine; the siloxane block polyvinyl ether hyperbranched amine is the siloxane block polyvinyl ether hyperbranched amine described in claim 4.

6. The preparation method according to claim 5, characterized in that: The mass ratio of the siloxane block polyvinyl ether hyperbranched amine, the chain extender and the catalyst is (200-400): (40-80): (6-12).

7. The polysiloxane block polyoxyethylene ether hyperbranched amine prepared by the preparation method according to claim 5.

8. Use of the siloxane block polyoxyethylene ether hyperbranched amine according to claim 4 or the polysiloxane block polyoxyethylene ether hyperbranched amine according to claim 7 in a toughening agent for epoxy resin materials.

9. An epoxy resin composite material, characterized in that: The epoxy resin composite material is obtained by mixing epoxy resin, a curing agent and a toughening agent and then curing the mixture. The toughening agent is the siloxane block polyoxyethylene ether hyperbranched amine described in claim 4 or the polysiloxane block polyoxyethylene ether hyperbranched amine described in claim 7.

10. A carbon fiber reinforced epoxy resin composite material, characterized in that: The carbon fiber reinforced epoxy resin composite material is obtained by mixing epoxy resin, a curing agent and a toughening agent, and then impregnating the carbon fiber with a vacuum-assisted method and then curing. The toughening agent is the siloxane block polyoxyethylene ether hyperbranched amine described in claim 4 or the polysiloxane block polyoxyethylene ether hyperbranched amine described in claim 7.

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