Reactive thermoplastic resin containing branched structure and preparation method and epoxy composition thereof

Abstract

The invention discloses a reaction type thermoplastic resin containing a branched structure, a preparation method and an epoxy composition thereof, and belongs to the technical field of high polymer materials, the structure is as follows: the resin has a long branched chain structure and an active end group, and compared with a thermoplastic resin with a linear structure, on the premise of similar number-average molecular weight, the resin has a higher specific surface area. The epoxy resin has more active end groups and better solubility, can participate in an epoxy resin curing reaction, forms holes in an epoxy system, improves phase separation and better absorbs impact energy. The preparation method comprises the following steps: adding phloroglucinol or 1, 2, 4-phloroglucinol, bisphenol, dihalogen diphenyl sulfone / ketone or dihalogen cyanophenyl into a polar aprotic solvent according to a certain proportion, adding a salt-forming agent sodium carbonate / potassium carbonate to carry out polymerization reaction, diluting with the polar aprotic solvent, acidifying, and carrying out a series of treatment to obtain the active hydroxyl-terminated branched polyether sulfone / ketone copolymer. Adding the copolymer into epoxy resin, and adding an anhydride curing agent to obtain the high-toughness epoxy resin composition.

Description

A reactive thermoplastic resin containing a branched structure, its preparation method, and its epoxy composition. Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a reactive thermoplastic resin with a branched structure, its preparation method, and its epoxy composition. Background Technology

[0002] Epoxy resin (EP), as one of the most commonly used thermosetting resins, possesses excellent mechanical and thermodynamic properties, along with significant advantages such as strong adhesion, corrosion resistance, and good chemical stability. Therefore, it is widely used in aerospace, mechanical and electronic fields, and adhesives. However, the poor impact resistance caused by the high crosslinking density of epoxy resin limits its application in structural materials. Therefore, improving the toughness of epoxy resin has always been a research hotspot in the field of materials science.

[0003] High-performance thermoplastic resins can be used for toughening modification of epoxy resins, maintaining the strength and modulus of the material system without lowering the service temperature. These include polyetherketone (PEK), polyethersulfone (PES), polyimide (PI), and polyetherimide (PEI). However, the toughening effect is limited due to poor thermoplastic-thermosetting interfacial compatibility.

[0004] Thermoplastic resins containing reactive groups (such as hydroxyl, carboxyl, and amine groups) can participate in the crosslinking reaction of epoxy systems, improving the thermoplastic-thermosetting interface properties and thus enhancing the impact toughness of the epoxy system. Patent CN202311414999.X discloses an epoxy resin composition containing an active side carboxyl group (phenolphthalein polyethersulfone / ketone) and its preparation method, obtained through high-temperature copolymerization of phenolphthalein, a carboxyl-containing compound, and a halogen compound. Due to the introduction of the active side carboxyl group, the cured product exhibits a homogeneous phase, and the impact strength increases by 82% when the addition amount is 5 phr.

[0005] Branched thermoplastic resins possess unique molecular structures and abundant end-group units, generally exhibiting advantages such as low viscosity and good solubility. While participating in the crosslinking reaction of epoxy resins, the thermoplastic polymer forms cavities within the system. Under synergistic effects, the branched thermoplastic resin demonstrates excellent toughening properties for epoxy resins. Patent CN201810030352.X discloses a carboxyl-side-group hyperbranched polyaryl ether copolymer modified epoxy resin composition and its preparation method. It is prepared by copolymerizing resorcinol, phenolphthalein, and dihalogen monomers. The composite material is then prepared with epoxy resin, curing agent, glass fiber, etc., and tested. In the examples, the flexural strength increased by 61%, the flexural modulus increased by 20%, the fracture flexural strain increased by 85%, the critical stress intensity factor increased by 32.1%, and the critical strain energy release rate increased by 47.8%. Patent CN202310236951.8 discloses a hydroxyl-terminated hyperbranched polyurethane modified epoxy resin and its preparation method. The synthesized hydroxyl-terminated hyperbranched polyurethane contains a large number of urethane groups and carbonyl groups, which endow the toughened epoxy system with excellent mechanical and interfacial properties. Compared with the untoughened epoxy resin, the peel strength after curing is increased by 200-300%. Summary of the Invention

[0006] This invention proposes a thermoplastic reactive toughening agent with a branched structure. By introducing a third trifunctional monomer into the molecular chain of linear polyarylene ether resin to form a long branched structure, and introducing an active hydroxyl group at the end of the polymer molecular chain to participate in the crosslinking of epoxy, the branched structure and the active end group work together to improve the toughening effect. Its toughening effect is better than that of traditional linear thermoplastic toughening agents.

[0007] This invention provides a branched reactive thermoplastic resin having the structure shown in Formula I:

[0008] In formula I, X is selected from one of the structures shown in formulas I-1 to I-6:

[0009] In formula I, Y is selected from one of the structures shown in formulas II-1 to II-3:

[0010] In Equation I, Z represents the structure shown in Equation III-1 or III-2.

[0011]

[0012] This resin has a long branched chain structure and active end groups. Compared with linear thermoplastic resins, it has more active end groups and better solubility under similar number-average molecular weight. It can participate in the epoxy resin curing reaction, form cavities in the epoxy system, improve phase separation, and better absorb impact energy.

[0013] Another object of the present invention is to provide a method for preparing the above-mentioned reactive thermoplastic resin, comprising the following steps: under an inactive atmosphere, a triphenol compound, a bisphenol compound, a dihalogen compound, a salt-forming agent, a dehydrating agent, and a polar aprotic solvent are mixed, heated to reflux to remove water, and then the dehydrating agent is evaporated. The temperature is then increased to carry out a polymerization reaction. After the reaction is completed, the temperature is lowered, a diluent is added, and then an acidification treatment is performed to obtain the reactive thermoplastic resin; wherein the dihalogen compound is selected from one or more of the structures shown in Formulas IV-1 to IV-3.

[0014] In this embodiment, R in formulas IV-1 to IV-3 is independently selected from fluorine and / or chlorine; the triphenol compound is selected from phloroglucinol or 1,2,4-phenylpyroglucinol; and the bisphenol compound is selected from one of the structures shown in formulas V-1 to V-6. .

[0015] In the preparation method described above, the molar ratio of the triphenol compound, bisphenol compound and dihalogen compound is 1:3n:3n (n=1~20); preferably, when n is 5~15, the reactive thermoplastic toughening agent of the polymerization product has the best effect on toughening epoxy resin.

[0016] In the preparation method described above, the salt-forming agent is selected from one or more of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate.

[0017] In the preparation method described above, the molar ratio of the bisphenol compound to the salt-forming agent is 1:1 to 1.5.

[0018] In the preparation method described above, the dehydrating agent is selected from toluene and / or xylene.

[0019] In the preparation method described above, the polar aprotic solvent is selected from one or more of sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0020] In the preparation method described above, the temperature for water removal is 140–160°C, and the water removal time is 1–3 hours.

[0021] Preferably, the water temperature is 150–160°C, and the water-carrying time is 2–3 hours.

[0022] Preferably, the temperature of the water is independently selected from any value of 140°C, 145°C, 150°C, 155°C, 160°C, or a range between any two of the above.

[0023] Preferably, the water-carrying time is independently selected from any value of 1h, 2h, 3h or a range between any two of the above.

[0024] In the preparation method described above, the polymerization reaction temperature is 180–220°C, and the polymerization reaction time is 1–6 h.

[0025] Preferably, the temperature of the polymerization reaction is independently selected from any value of 180°C, 190°C, 200°C, 210°C, 220°C, or a range between any two of the above.

[0026] Preferably, the polymerization reaction time is independently selected from any value of 1h, 2h, 3h, 4h, 5h, 6h or a range between any two of the above.

[0027] In the preparation method described above, the acid used for acidification is at least one or more of hydrochloric acid, dilute sulfuric acid, dilute nitric acid, formic acid, and acetic acid, and the acidification time is 12-24 hours.

[0028] As described above, after the reaction is completed, the temperature is lowered to 100°C. The diluent is selected from N,N-dimethylformamide and N,N-dimethylacetamide. The diluent is required to dilute the solid content of the reaction system to 1%~10%.

[0029] Another object of the present invention is to provide an epoxy composition prepared from an epoxy resin, a curing agent, and a reactive thermoplastic resin containing a branched structure; wherein the reactive thermoplastic resin containing a branched structure is selected from the above-mentioned reactive thermoplastic resins; and wherein the epoxy resin is selected from one or more of epoxy resin E51, epoxy resin E44, epoxy resin E54, epoxy resin E42, epoxy resin E31, epoxy resin E21, epoxy resin E20, epoxy resin E12, epoxy resin E03, and epoxy resin E06.

[0030] The curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and phthalic anhydride.

[0031] In the epoxy composition described above, the reactive thermoplastic resin has a mass of 5 to 20 wt% of the epoxy resin.

[0032] Preferably, the mass of the reactive thermoplastic resin is independently selected from any value of 5wt%, 10wt%, 15wt%, 20wt%, or a range between any two of the above.

[0033] In the epoxy composition described above, the amount of curing agent is 20 to 80 wt% of the epoxy resin.

[0034] As a specific implementation plan, this application is achieved through the following technical solution: The preparation method of branched reactive thermoplastic resin is as follows: Step 1: Dissolve triphenol monomer, bisphenol monomer, and dihalogen monomer in a polar aprotic solvent, add salting agent and dehydrating agent, and stir under nitrogen atmosphere.

[0035] The molar ratio of triphenol monomer, bisphenol monomer, and dihalogen monomer is 1:3n:3n (n=1~20), the water-carrying temperature is 140~160℃, the water-carrying time is 2h, the polymerization temperature is 180~220℃, and the reaction time is 1~6h.

[0036] Step 2: After the reaction is complete, pour the reaction solution into a polar aprotic solvent containing an acidic reagent for dilution and stirring. The acidification time is 12-24 hours. Step 3: Pour the acidified reaction solution into a mixed solution of ethanol and water (volume ratio = 3:1). The precipitate is filtered, crushed, boiled, and dried to obtain a reactive polyarylether ketone / sulfone resin with a branched structure.

[0037] Due to the adoption of the above technical solution, the beneficial effects of this invention are as follows: This invention discloses a reactive thermoplastic resin containing a branched structure, its preparation method, and an epoxy composition containing the reactive thermoplastic resin. The reactive thermoplastic resin containing a branched structure contains active reactive groups that can participate in the epoxy resin curing reaction to improve the interfacial properties of the thermoplastic-thermoplastic phase. This thermoplastic resin has a long-branched structure, which, compared with linear thermoplastic resins of the same molecular weight, has better solubility and lower viscosity. Furthermore, the long branches cause an increase in the free volume of the polymer, forming cavities that can absorb impact energy and synergistically improve the impact toughness of the system. This reactive thermoplastic resin is simple to prepare; adding a small amount of toughening agent resin (5 phr) can significantly improve the impact strength of the system, and the toughening effect is far superior to that of traditional linear thermoplastic toughening agents. Attached Figure Description

[0038] Figure 1 shows the structural formula of phloroglucinol after one hydroxyl group is substituted; Figure 2 shows the structural formula of phloroglucinol after two hydroxyl groups are substituted; Figure 3 shows the structural formula of phloroglucinol after all three hydroxyl groups are substituted; Figure 4 shows the branched reactive thermoplastic resins prepared in Examples 1-4 of this application. 1 H-NMR spectrum; Figure 5 is a SEM image of the LCBPES / E51 cured system prepared in Examples 6 to 11 of this application, with a scale bar of 20 μm. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0041] The raw materials used in the embodiments of this application were all purchased through commercial channels.

[0042] The performance testing and detection equipment for the materials in this application are as follows: Nuclear magnetic resonance spectrometer (AV-III 400MHz, Bruker) was used to record... 1 H-NMR spectrum was obtained using DMSO-d6 as the test solvent; the cross-sectional morphology of the modified epoxy resin was observed using a scanning electron microscope (HITACHI SU1000); the specific viscosity was obtained by dissolving 0.125g of resin sample in 25ml of DMF and measuring it in a constant temperature water bath at 25℃ using an Ubbelohde viscometer.

[0043] Impact performance was tested according to GB / T 1843-2023 using a cantilever beam combined impact testing machine (DigitalImpactTester). The test conditions were 2.9 m / s², pendulum energy of 7.5 J, span of 60 mm, and spline dimensions of 80 mm * 10 mm * 4 mm.

[0044] Example 1: Three monomers, phloroglucinol (PG), phenolphthalein (PHT), and difluorodiphenyl sulfone (DFDBS), were subjected to S... N 2. Nucleophilic polymerization reaction for 6 h yielded a branched reactive polyarylene ether sulfone LCBPES with a specific viscosity of 0.09 dL / g, named LCBPES-3.

[0045] Under nitrogen protection, a mixture of 1.681 g (13.33 mmol) phloroglucinol (PG), 12.733 g (40 mmol) phenolphthalein (PHT), 10.170 g (40 mmol) difluorodiphenyl sulfone (DFDBS), and 9.536 g (60 mmol) potassium carbonate (K2CO3) was added to a 250 ml three-necked round-bottom flask containing 81 ml sulfolane and 40 ml xylene. The mixture was heated to reflux at 175 °C for 3 h to remove xylene by removing water, and then the temperature was raised to 210 °C for 6 h. After cooling to room temperature, 81 ml DMAc was added for dilution, and the mixture was quantitatively acidified with glacial acetic acid for 12 h. The mixture was then precipitated in an ethanol and deionized water (3:1) precipitation solution, washed with deionized water until neutral, and then dried in a forced-air oven at 120 °C for 24 h, followed by drying in a vacuum oven at 120 °C for 24 h to obtain white LCBPES.

[0046] Example 2 describes the use of three monomers, phloroglucinol (PG), phenolphthalein (PHT), and difluorodiphenyl sulfone (DFDBS), via S... N 2. Nucleophilic polymerization reaction for 6 h yielded a branched reactive polyarylene ether sulfone LCBPES with a specific viscosity of 0.23 dL / g, named LCBPES-15.

[0047] Under nitrogen protection, a mixture of 0.341 g (2.7 mmol) phloroglucinol (PG), 12.733 g (40 mmol) phenolphthalein (PHT), 10.170 g (40 mmol) difluorodiphenyl sulfone (DFDBS), and 7.001 g (50.6 mmol) potassium carbonate (K2CO3) was added to a 250 ml three-necked round-bottom flask containing 70 ml sulfolane and 35 ml xylene. The mixture was heated to reflux at 175 °C for 3 h to remove xylene by removing water, and then the temperature was raised to 210 °C for 6 h. After cooling to room temperature, 70 ml DMAc was added for dilution, and the mixture was quantitatively acidified with glacial acetic acid for 12 h. The mixture was then precipitated in an ethanol and deionized water (3:1) precipitation solution, washed with deionized water until neutral, and then dried in a forced-air oven at 120 °C for 24 h, followed by drying in a vacuum oven at 120 °C for 24 h to obtain white LCBPES.

[0048] Example 3 describes the use of three monomers, phloroglucinol (PG), phenolphthalein (PHT), and difluorodiphenyl sulfone (DFDBS), via S... N 2. Nucleophilic polymerization reaction for 6 h yielded a branched reactive polyarylene ether sulfone LCBPES with a specific viscosity of 0.26 dL / g, named LCBPES-30.

[0049] Under nitrogen protection, a mixture of 0.164 g (1.3 mmol) phloroglucinol (PG), 12.733 g (40 mmol) phenolphthalein (PHT), 10.170 g (40 mmol) difluorodiphenyl sulfone (DFDBS), and 6.675 g (48.2 mmol) potassium carbonate (K2CO3) was added to a 250 mL three-necked round-bottom flask containing 70 mL sulfolane and 35 mL xylene. The mixture was heated to reflux at 175 °C for 3 h to remove xylene by removing water, and then the temperature was raised to 210 °C for 6 h. After cooling to room temperature, 70 mL of DMAc was added for dilution, and the mixture was quantitatively acidified with glacial acetic acid for 12 h. The mixture was then precipitated in an ethanol and deionized water (3:1) precipitation solution, washed with deionized water until neutral, and then dried in a forced-air oven at 120 °C for 24 h, followed by drying in a vacuum oven at 120 °C for 24 h to obtain white LCBPES.

[0050] Example 4: Three monomers, phloroglucinol (PG), phenolphthalein (PHT), and difluorodiphenyl sulfone (DFDBS), were subjected to S... N 2. Nucleophilic polymerization reaction for 6 h yielded a branched reactive polyarylene ether sulfone LCBPES with a specific viscosity of 0.35 dL / g, named LCBPES-45.

[0051] Under nitrogen protection, a mixture of 0.112 g (0.89 mmol) phloroglucinol (PG), 12.733 g (40 mmol) phenolphthalein (PHT), 10.170 g (40 mmol) difluorodiphenyl sulfone (DFDBS), and 6.570 g (47.53 mmol) potassium carbonate (K2CO3) was added to a 250 ml three-necked round-bottom flask containing 69 ml sulfolane and 39 ml xylene. The mixture was heated to reflux at 175 °C for 3 h to remove xylene by removing water, and then the temperature was raised to 210 °C for 6 h. After cooling to room temperature, 69 ml DMAc was added for dilution, and the mixture was quantitatively acidified with glacial acetic acid for 12 h. The mixture was then precipitated in an ethanol and deionized water (3:1) precipitation solution, washed with deionized water until neutral, and then dried in a forced-air oven at 120 °C for 24 h, followed by drying in a vacuum oven at 120 °C for 24 h to obtain white LCBPES.

[0052] The LCBPES prepared in Examples 1-4 were tested. Figure 4 shows the results of the prepared reactive thermoplastic resins containing branched structures. 1The H-NMR spectra, from top to bottom, are LCBPES-3, LCBPES-15, LCBPES-30, and LCBPES-45. Characteristic peaks of two terminal hydroxyl groups appear at chemical shifts of 9.73 and 10.63, confirming the successful synthesis of the hydroxyl-terminated branched reactive polyarylene sulfone. The gradual decrease in the size of these two characteristic peaks from top to bottom is due to the decreasing amount of phloroglucinol (PG) used during the preparation process, resulting in less residual PG in the system.

[0053] Example 5 describes the use of three monomers, phloroglucinol (PG), phenolphthalein (PHT), and difluorodiphenyl sulfone (DFDBS), via S... N 2. Nucleophilic polymerization reaction for 6 h yielded a branched reactive polyarylene ether sulfone LCBPES with a specific viscosity of 0.40 dL / g, named LCBPES-60.

[0054] Under nitrogen protection, a mixture of 0.084 g (0.67 mmol) phloroglucinol (PG), 12.733 g (40 mmol) phenolphthalein (PHT), 10.170 g (40 mmol) difluorodiphenyl sulfone (DFDBS), and 6.517 g (47.2 mmol) potassium carbonate (K2CO3) was added to a 250 ml three-necked round-bottom flask containing 68 ml sulfolane and 35 ml xylene. The mixture was heated to reflux at 175 °C for 3 h to remove xylene by removing water, and then the temperature was raised to 210 °C for 6 h. After cooling to room temperature, 68 ml DMAc was added for dilution, and the mixture was quantitatively acidified with glacial acetic acid for 12 h. The mixture was then precipitated in an ethanol and deionized water (3:1) precipitation solution, washed with deionized water until neutral, and then dried in a forced-air oven at 120 °C for 24 h, followed by drying in a vacuum oven at 120 °C for 24 h to obtain white LCBPES.

[0055] Example 6 Preparation of epoxy compounds: By weight, 100 phr of epoxy resin, 72 phr of curing agent Me-THPA, and 5 phr of branched reactive polyarylether sulfone LCBPES-3 powder prepared in Example 1.

[0056] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPES-3 resin is added. The mixture is heated to 80℃ and stirred until LCBPES-3 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazole is added and stirred. The mixture is cured at 110℃ / h~130℃ / h~160℃ / 4h, and then allowed to cool naturally. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0057] Figure 5(a) shows the SEM image of the E51 / LCBPES-3 cured system. It can be seen that the E51 / LCBPES-3 cured system does not show obvious island structure and is a homogeneous system as a whole.

[0058] In Example 7, by weight, the amount of epoxy resin was 100 phr, the amount of curing agent Me-THPA was 72 phr, and the amount of branched reactive polyarylether sulfone LCBPES-15 powder prepared in Example 2 was 5 phr.

[0059] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPES-15 resin is added. The mixture is heated to 80 °C and stirred until LCBPES-15 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazole is added and stirred. The mixture is cured using a curing process of 110 °C for 1 h to 130 °C for 1 h to 160 °C for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0060] Figure 5(b) shows the SEM image of the E51 / LCBPES-15 cured system. It can be seen that the E51 / LCBPES-15 cured system does not show obvious island structure and is a homogeneous system as a whole.

[0061] Example 8

[0062] By weight, the epoxy resin is 100 phr, the curing agent Me-THPA is 72 phr, and the branched reactive polyarylether sulfone LCBPES-30 powder prepared in Example 3 is added at a rate of 5 phr.

[0063] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPES-30 resin is added. The mixture is heated to 80 ℃ and stirred until LCBPES-30 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazole is added and stirred. The mixture is cured using a curing process of 110 ℃ for 1 h to 130 ℃ for 1 h to 160 ℃ for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0064] Figure 5(c) shows the SEM image of the E51 / LCBPES-30 cured system. It can be seen that the E51 / LCBPES-30 cured system exhibits a distinct island structure and crack deflection patterns on the cross section.

[0065] In Example 9, by weight, 100 phr of epoxy resin, 72 phr of curing agent Me-THPA, and 5 phr of the branched reactive polyarylether sulfone LCBPES-45 powder prepared in Example 4 were added.

[0066] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPES-45 resin is added. The mixture is heated to 80 ℃ and stirred until LCBPES-45 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazole is added and stirred. The mixture is cured using a curing process of 110 ℃ for 1 h to 130 ℃ for 1 h to 160 ℃ for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0067] Figure 5(d) shows the SEM image of the E51 / LCBPES-45 cured system. It can be seen that the E51 / LCBPES-45 cured system exhibits a distinct island structure and crack deflection patterns on the cross section.

[0068] In Example 10, by weight, 100 phr of epoxy resin, 72 phr of curing agent Me-THPA, and 5 phr of the branched reactive polyarylether sulfone LCBPES-60 powder prepared in Example 5 were added.

[0069] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPES-60 resin is added. The mixture is heated to 80℃ and stirred until LCBPES-60 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazole is added and stirred. The mixture is cured using a curing process of 110℃ for 1 hour to 130℃ for 1 hour to 160℃ for 4 hours, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0070] Figure 5(e) shows the SEM image of the E51 / LCBPES-60 cured system. It can be seen that the E51 / LCBPES-60 cured system exhibits a distinct island structure and crack deflection patterns on the cross section.

[0071] Example 11: by weight, epoxy resin 100 phr, curing agent Me-THPA 72 phr.

[0072] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, the mixture is heated to 80 ℃ to completely dissolve. Then, accelerator 2-ethyl-4-methylimidazolium is added and stirred. The mixture is cured using a curing process of 110 ℃ for 1 h, 130 ℃ for 1 h, and 160 ℃ for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0073] Figure 5(f) shows the SEM image of the fracture section of the E51 epoxy system. No obvious island structure is observed, indicating a homogeneous system and brittle fracture.

[0074] Comparative Example 1: By mass, 100 phr of epoxy resin, 72 phr of curing agent Me-THPA, and 5 phr of long-branched polymer LCBPESC-30 powder (specific viscosity 0.29 dL / g) prepared by replacing phloroglucinol with 1,1,1-tris(4-hydroxyphenyl)ethane (THPE) as toughening agent.

[0075] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, LCBPESC-30 resin is added. The mixture is heated to 80 ℃ and stirred until LCBPESC-30 is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazolium is added and stirred. The mixture is cured using a curing process of 110 ℃ for 1 h, 130 ℃ for 1 h, and 160 ℃ for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0076] Comparative Example 2: by weight, 100 phr of epoxy resin, 72 phr of Me-THPA curing agent, and 5 phr of PES resin powder (product of Shandong Haoran Special Plastics Co., Ltd., specific viscosity 0.3 dL / g) as toughening agent were added.

[0077] After E-51 epoxy resin and curing agent Me-THPA are mixed evenly at room temperature, PES is added, and the mixture is heated to 80 ℃ and stirred until the PES is completely dissolved. Then, accelerator 2-ethyl-4-methylimidazolium is added and stirred. The mixture is cured using a curing process of 110 ℃ for 1 h to 130 ℃ for 1 h to 160 ℃ for 4 h, followed by natural cooling. Samples are prepared according to national standard GB / T1043.1-2008 for later use.

[0078] The epoxy compositions prepared in Examples 6-11 and Comparative Examples 1-2 were subjected to impact performance tests, and the results are shown in Tables 1 and 2.

[0079] Table 1 Impact Performance Test Table of Epoxy Systems in Examples 6-11 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 LCBPES Dosage (phr) 5 5 5 5 0 LCBPES Source LCBPES-3 LCBPES-15 LCBPES-30 LCBPES-45 LCBPES-60 -- Unnotched Impact Strength (kJ / m) 2 16.32 21.78 25.45 22.63 16.58 8.34 surface

[0080] The addition of reactive thermoplastic LCBPES with branched structure significantly improves the impact toughness of epoxy systems.

[0081] Table 2 Impact Performance Test Table of Epoxy Systems in Comparative Examples 1-2

[0082] As shown in Tables 1 and 2, all series of LCBPES have a toughening effect on epoxy resin, and the impact strength first increases and then decreases as the amount of PG in the LCBPES structure decreases. The LCBPES exhibits the best toughening effect within the PG to PHT molar ratio range of 1:15 to 1:45. In Example 8, the impact strength of the system toughened with LCBPES-30 is 25.45 kJ / m². 2 Compared to the epoxy system without toughening agent in Example 11 (8.34 kJ / m 2 This represents a 205% increase, compared to control 1 (impact strength 20.31 kJ / m). 2 The impact strength has been significantly improved, far exceeding that of Comparative Example 2 (impact strength 10.29 kJ / m). 2 The reason can be attributed to the fact that LCBPES forms island-shaped or homogeneous structures in epoxy resin. When impact energy arrives, both island-shaped and homogeneous structures can absorb the impact energy. Furthermore, the introduction of reactive groups allows for better interfacial interaction between the thermoplastic resin and the epoxy system, further enhancing impact strength. At the same time, the branched structure forms voids in the system. The synergistic effect of these three factors gives LCBPES an excellent toughening effect on epoxy systems.

[0083] The above descriptions are merely a few embodiments of this application and are not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, they are not intended to limit this application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of this application, based on the disclosed technical content, are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A reactive thermoplastic resin containing a branched structure, characterized in that: It has the structure shown in Equation I: In formula I, X is selected from one of the structures shown in formulas I-1 to I-6: In formula I, Y is selected from one of the structures shown in formulas II-1 to II-3: In Equation I, Z is selected from the structure shown in Equation III-1 or Equation III-2. 。 2. The method for preparing the branched reactive thermoplastic resin according to claim 1, characterized in that, Includes the following steps: Under an inactive atmosphere, a triphenol compound, a bisphenol compound, a dihalogen compound, a salt-forming agent, a dehydrating agent, and a polar aprotic solvent are mixed, heated to reflux, and after dehydration, the dehydrating agent is evaporated. The temperature is then increased to carry out the polymerization reaction. After the reaction is completed, the temperature is lowered, a diluent is added, and then acidification treatment is performed to obtain a reactive thermoplastic resin. The dihalogen compound is selected from one of the structures shown in Formulas IV-1 to IV-3. In formulas IV-1, IV-2, and IV-3, R is independently selected from fluorine and / or chlorine; the triphenol compound is selected from phloroglucinol or 1,2,4-phenylpyroglucinol; and the bisphenol compound is selected from one of the structures shown in formulas V-1 to V-6. 。 3. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The molar ratio of the triphenol compound, bisphenol compound and dihalogen compound is 1:3n:3n, where n = 1 to 20, and the molar ratio of the bisphenol compound and the salt-forming agent is 1:1 to 1.

5.

4. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The salt-forming agent is selected from one or a combination of sodium hydroxide, potassium hydroxide, potassium carbonate, and sodium carbonate.

5. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The water-removing agent is selected from toluene and / or xylene.

6. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The polar aprotic solvent is selected from at least one of sulfolane, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

7. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The water-carrying temperature is 140–160℃, and the water-carrying time is 1–3 h; the polymerization reaction temperature is 180–220℃, and the polymerization reaction time is 1–6 h.

8. The method for preparing a branched reactive thermoplastic resin according to claim 2, characterized in that: The acid used for acidification is selected from at least one of hydrochloric acid, dilute sulfuric acid, dilute nitric acid, formic acid, and acetic acid. The acidification time is 12-24 hours. The diluent is selected from one of N,N-dimethylformamide and N,N-dimethylacetamide. After the reaction is completed, the temperature is lowered to 100°C. After the diluent is added, the solid content of the reaction system is diluted to 1%-10%.

9. An epoxy composition, characterized in that: The product is obtained by blending epoxy resin, curing agent, and reactive thermoplastic resin; the reactive thermoplastic resin is selected from the reactive thermoplastic resin described in claim 1; the epoxy resin is selected from one or more of epoxy resin E51, epoxy resin E44, epoxy resin E54, epoxy resin E42, epoxy resin E31, epoxy resin E21, epoxy resin E20, epoxy resin E12, epoxy resin E03, and epoxy resin E06; the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and phthalic anhydride.

10. The epoxy composition according to claim 9, characterized in that: The reactive thermoplastic resin is 5-20 wt% of the epoxy resin, and the curing agent is 20-80 wt% of the epoxy resin.

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