A modified furfural resin for impregnation and its preparation method and application

Abstract

The present application relates to the field of carbon-carbon composite material densification aids, and specifically to a modified furfural resin for impregnation, and a preparation method and application thereof. A modified furfural resin for impregnation, comprising the following components in parts by weight: 100 parts of furfural resin, 5-50 parts of modifier; the modifier is a mixture of bismaleimide, allyl compound and organic diamine; bismaleimide includes at least one of 4,4'-bismaleimide diphenylmethane and N,N'-m-phenylene bismaleimide; the allyl compound includes at least one of 2,2'-diallyl bisphenol A and allyl phenol formaldehyde; the organic diamine includes at least one of 4,4'-diaminodiphenylmethane and dicyandiamide. The present application uses the modifier composed of the above substances to act on the furfural resin together to form a highly cross-linked network structure, thereby significantly improving the residual carbon rate. The components in the modifier produce a synergistic effect, further enhancing the stability of the carbonized product.

Description

Technical Field

[0001] The present application relates to the field of carbon-carbon composite material densification aids, and specifically to a modified furfural resin for impregnation, and a preparation method and application thereof. Background Art

[0002] Furfural ketone resin is a thermosetting resin formed by the condensation reaction of furfural and acetone under alkaline conditions. It can be further polycondensed with formaldehyde under acidic conditions to connect the furfural ketone monomer molecules through methyl bonds to form furfural acetone resin. Furfural ketone resin contains furan rings and has a stable furan ring structure. Furfural ketone resin has good heat resistance. After carbonization treatment in a nitrogen atmosphere, the residual carbon rate is 58%. It is a widely used impregnating agent for densification of carbon-carbon composite matrix.

[0003] In order to obtain high-density carbon-carbon composite materials, multiple cycles of impregnation and carbonization are required. How to shorten the impregnation and carbonization cycle of carbon-carbon composite materials is a key issue in the current production of carbon-carbon composite materials. The decisive factor in shortening the impregnation and carbonization cycle of carbon-carbon composite materials is the residual carbon rate of furfural resin. Therefore, the development of a high residual carbon modified furfural resin for impregnation is an urgent problem to be solved. Summary of the invention

[0004] In order to solve the problem that the residual carbon rate of furfural resin is difficult to meet the requirements of shortening the impregnation carbonization cycle of carbon-carbon composite materials, the present application provides a modified furfural resin for impregnation, and the present application uses a modifier composed of bismaleimide, an allyl compound and an organic diamine to act on the furfural resin to form a highly cross-linked network structure. This structure can effectively resist pyrolysis and oxidation during the carbonization process, thereby significantly improving the residual carbon rate, thereby shortening the impregnation carbonization cycle of the carbon-carbon composite material.

[0005] In the first aspect, the present application provides a modified furfural resin for impregnation, which adopts the following technical solution: A modified furfural resin for impregnation, comprising the following components in parts by weight: 100 parts of furfural resin and 5-50 parts of a modifier; the modifier is a mixture of bismaleimide, an allyl compound and an organic diamine; The bismaleimide comprises at least one of 4,4'-bismaleimide diphenylmethane and N,N'-m-phenylene bismaleimide; The allyl compound includes at least one of 2,2'-diallyl bisphenol A and allyl phenol formaldehyde; The organic diamine includes at least one of 4,4'-diaminodiphenylmethane and dicyandiamide.

[0006] By adopting the above technical solution, bismaleimide (such as 4,4'-bismaleimide diphenylmethane and N,N'-m-phenylene bismaleimide) has high thermal stability and good cross-linking performance. The introduction of bismaleimide into the resin can increase the rigidity of the molecular chain and improve the thermal stability of the resin. During the carbonization process, the cross-linked structure of bismaleimide helps to form a more stable carbon skeleton, thereby increasing the residual carbon rate.

[0007] Allyl compounds (such as 2,2'-diallyl bisphenol A and allyl phenol formaldehyde) contain unsaturated double bonds and are prone to chemical reactions with other components. These compounds can undergo cross-linking reactions with bismaleimide and organic diamines to form a more complex and stable network structure. During carbonization, this network structure can more effectively resist pyrolysis and oxidation, thereby retaining more carbonaceous materials.

[0008] Organic diamines (such as 4,4'-diaminodiphenylmethane and dicyandiamide) have active amino functional groups that can react with other functional groups in the resin. These amino functional groups not only participate in the cross-linking reaction, but also form nitrogen heterocyclic structures during the carbonization process, further improving the stability of the carbonized product.

[0009] The present application uses a modifier composed of bismaleimide, an allyl compound and an organic diamine to act together on the furfural resin to form a highly cross-linked network structure. This structure can effectively resist pyrolysis and oxidation during the carbonization process, thereby significantly improving the residual carbon rate. The components in the modifier may also interact with each other to produce a synergistic effect, further enhancing the stability of the carbonized product.

[0010] Preferably, the modifier is a mixture of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane.

[0011] By adopting the above technical solution, the combination of 4,4'-bismaleimide diphenylmethane (BMI), 2,2'-diallyl bisphenol A (DBA) and 4,4'-diaminodiphenylmethane (MDA) as a modifier is considered to be the best combination compared with other combinations. The characteristics of each substance are excellent.

[0012] BMI has excellent heat resistance, its glass transition temperature (Tg) is generally greater than 250°C, and the operating temperature range is about 177°C-232°C. This high thermal stability helps the modified resin maintain stable performance in high temperature environments. The imide heterocycle and cross-linking density in the BMI molecule are high, so that its cured product has excellent heat resistance and mechanical properties. Introducing BMI into the resin can increase the rigidity of the molecular chain and improve the overall performance of the resin.

[0013] The allyl and bisphenol A groups in DBA give it excellent reactivity, enabling it to undergo effective cross-linking reactions with other components. MDA has active amino functional groups that are easy to react with other functional groups to form stable chemical bonds. The amino functional groups of MDA can participate in the cross-linking reaction of the resin, further enhancing the curing effect and improving the thermal stability and mechanical properties of the resin.

[0014] The combined effect of BMI, DBA and MDA can form a more complex and stable network structure. This structure can more effectively resist pyrolysis and oxidation during the carbonization process, thereby retaining more carbonaceous materials. Due to the synergistic effect of the three, the modified resin can form a more stable carbon skeleton during the carbonization process, thereby significantly improving the residual carbon rate.

[0015] Preferably, the molar ratio of the 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane is 1:(1-5):(1-5).

[0016] By adopting the above technical solution, if the molar ratio of DBA and MDA is too low, the cross-linking points formed by their reaction with BMI will be reduced, resulting in insufficient cross-linking density of the resin. The reduction in cross-linking density will affect the thermal stability and mechanical properties of the resin, making it prone to deformation or cracking under high temperature or stress. DBA and MDA are active functional group providers, and their insufficient content may lead to incomplete curing reaction of BMI. Incompletely cured resin will contain unreacted functional groups, which may degrade at high temperatures, affecting the thermal stability and carbon residue rate of the resin.

[0017] When the molar ratio of DBA and MDA is too high, the content of 4,4'-bismaleimide diphenylmethane is relatively small, and the cross-linking network is already sufficiently stable at this time. Continuing to increase DBA and MDA will reduce the carbon residue rate of the resin.

[0018] Preferably, the mass ratio of the furfural resin to the modifier is 100:5-30.

[0019] By adopting the above technical solution, if the content of the modifier is too low, then its improvement on the performance of furfural resin will be very limited. Especially in terms of improving heat resistance and carbon residue rate, the effect of the modifier will not be obvious, and may even fail to achieve the expected effect. If the content of the modifier is too high, since the modifier composed of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane has excellent performance, it is difficult to continue to increase the carbon residue rate with a higher content.

[0020] Preferably, the preparation method of the modifier comprises the following steps: The modified agent is obtained by mixing the bismaleimide, the allyl compound and the organic diamine in the formula amount and then performing a melting reaction.

[0021] By adopting the above technical solution, the melt reaction is usually carried out at a higher temperature, which helps to speed up the reaction rate and improve the reaction efficiency. The molten state allows for more complete contact between the reactant molecules, which is conducive to the reaction. Compared with other reaction methods, such as solution reactions or solid-phase reactions, melt reactions usually do not require additional solvents or catalysts, and the reaction conditions are relatively mild. During the melt reaction, the reactants are directly converted into products, avoiding problems such as solvent residues or catalyst residues. This helps to obtain modifiers with higher purity to meet the needs of high-end applications.

[0022] Preferably, the reaction temperature of the melt reaction is 70-180° C., and the reaction time is 1-5 h.

[0023] By adopting the above technical scheme, temperature is an important factor affecting the rate of chemical reactions. At lower temperatures, the movement speed of the reactant molecules slows down and the collision frequency decreases, resulting in a decrease in the reaction rate. If the temperature is too low, the reaction may not proceed or proceed very slowly, resulting in low production efficiency. At lower temperatures, the reaction may not be complete, resulting in unreacted reactants remaining in the product. This will not only reduce the purity of the product, but may also affect the performance of the product. At high temperatures, the reactants may undergo thermal degradation, resulting in decreased product performance. Especially for some heat-sensitive compounds, high temperatures are more likely to trigger degradation reactions.

[0024] A shorter reaction time may not ensure that the reaction is complete. If the reaction time is insufficient, unreacted reactants or intermediates may remain in the product, which will affect the purity and performance of the product. For a longer time, the reactants are fully melted and there is no need to continue to increase the heating time.

[0025] In the second aspect, the present application provides a method for preparing a modified furfural resin for impregnation, adopting the following technical scheme: a method for preparing a modified furfural resin for impregnation, used to prepare the above-mentioned modified furfural resin for impregnation, comprising the following steps: mixing the formula amount of furfural resin and modifier and heating them to react to obtain the modified furfural resin for impregnation.

[0026] By adopting the above technical solution, the modifier can improve the heat resistance of furfural resin, so that it can still maintain stable performance in high temperature environment.

[0027] Preferably, the reaction temperature of the heating reaction is 70-150° C., and the reaction time is 1-5 h.

[0028] By adopting the above technical solution, lower temperatures may lead to incomplete reactions, and unreacted reactants or intermediates may remain in the products, affecting the purity and performance of the products. At high temperatures, reactants or products may undergo thermal degradation, resulting in reduced performance.

[0029] A shorter reaction time may not ensure that the reaction is complete. If the reaction time is insufficient, unreacted reactants or intermediates may remain in the product, affecting the purity and performance of the product. For a longer time, the reactants are fully melted and there is no need to continue to increase the heating time.

[0030] In a third aspect, the present application provides an application of a modified furfural resin for impregnation, using the following technical solution: The invention discloses an application of a modified furfural resin for impregnation, wherein the modified furfural resin for impregnation is applied in the impregnation and densification of carbon-carbon composite materials.

[0031] By adopting the above technical solution, the modified furfural resin for impregnation has a higher carbon residue rate than the conventional furfural resin, and the impregnation cycle can be reduced for the preparation of high-density carbon-carbon composite materials.

[0032] In summary, this application has the following beneficial effects: The present application uses a modifier composed of bismaleimide, an allyl compound and an organic diamine to act together on the furfural resin to form a highly cross-linked network structure. This structure can effectively resist pyrolysis and oxidation during the carbonization process, thereby significantly improving the residual carbon rate. The components in the modifier may also interact with each other to produce a synergistic effect, further enhancing the stability of the carbonized product. DETAILED DESCRIPTION

[0033] The raw materials in this application include the following parts: Furfuryl ketone resin: a commercially available product, such as that of Wuhan Kanosi Technology Co., Ltd.; 4,4'-Bismaleimidodiphenylmethane: a commercially available product with CAS No. 13676-54-5; N,N'-m-phenylene bismaleimide: a commercial product with CAS number 3006-93-7; 2,2'-Diallylbisphenol A: a commercially available product with CAS No. 1745-89-7; Allylphenolformaldehyde: a commercially available product with CAS number 68186-14-1; 4,4'-Diaminodiphenylmethane: a commercially available product with CAS No. 101-77-9; Dicyandiamide: a commercial product with CAS No. 461-58-5 was used; The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0034] Example 1 A method for preparing a modifier comprises the following steps: 1 mol of 4,4'-bismaleimide diphenylmethane, 3 mol of 2,2'-diallyl bisphenol A and 3 mol of 4,4'-diaminodiphenylmethane were mixed and melt-reacted at a reaction temperature of 150° C. for 5 hours to obtain a modifier.

[0035] A method for preparing a modified furfural resin for impregnation comprises the following steps: 100 g of furfural resin and 30 g of modifier were mixed and heated for reaction at a temperature of 120° C. for 5 h to obtain modified furfural resin for impregnation.

[0036] Embodiment 2-4 In Example 2-4, based on the preparation method of Example 1, the amount of the modifier added was adjusted, and the specific adjustment is shown in Table 1.

[0037] Comparative Example 1 Comparative Example 1 is only the furanone resin of Example 1.

[0038] Comparative Example 2 Based on the preparation method of Example 1, the amount of the modifier added was adjusted, and the specific adjustment is shown in Table 1.

[0039] Table 1 Addition amount and performance test table of modifiers of Examples 1-4 and Comparative Examples 1-2 Performance Test The modified furfural resin for impregnation of Examples 1-4 and Comparative Examples 1-2 was subjected to the following performance tests. The test results are shown in Table 1.

[0040] Carbon Residue Rate 100g of modified furfural resin for impregnation is selected and added to a crucible, and 0.4g of a curing agent is added to form a mixture. The curing agent can be benzenesulfonic acid, p-chlorobenzenesulfonic acid, etc., and benzenesulfonic acid is used as the curing agent in this application. The mixture is placed in a special equipment and carbonized at 950°C. After the carbonized sample is cooled, it is weighed and recorded as M grams, and the residual carbon rate is calculated as (M / 100)*100%.

[0041] Referring to Table 1, by comparing Examples 1-4 with Comparative Example 1-2, it can be seen that compared with Comparative Example 1, the carbon residue rates of Examples 1-4 are much higher than those of Comparative Example 1. This indicates that the addition of the modifier can effectively increase the carbon residue rate of the furfural resin.

[0042] As the amount of modifier added increases, the carbon residue rate of the modified furfural resin for impregnation increases until it stabilizes, which may be due to the combined action of the substances in the modifier on the furfural resin to form a highly cross-linked network structure. This structure can effectively resist pyrolysis and oxidation during the carbonization process, thereby significantly improving the carbon residue rate of the modified furfural resin for impregnation.

[0043] In addition, by comparing Examples 1-4, it is found that Example 1 has the best comprehensive performance, so Example 1 is preferred.

[0044] Embodiment 5-9 Example 5-9 Based on the preparation method of Example 1, the molar ratio of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane was adjusted. The specific adjustment is shown in Table 2.

[0045] The impregnation modified furfural resins of Examples 5-9 were subjected to the above performance tests, and the test results are shown in Table 2.

[0046] Table 2 Molar ratios of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane and performance test table of Example 1 and Examples 5-9 project Example 1 Example 5 Example 6 Example 7 Example 8 Example 9 The molar ratio of the three 1:3:3 1:1:1 1:1:5 1:5:1 1:5:5 2:1:1 Residual carbon rate / % 70.4 66.8 68.7 69.3 67.1 65.2 Referring to Table 2, by comparing Example 1 with Examples 5-9, it can be seen that as the molar ratio of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane continues to decrease, the residual carbon rate shows a trend of first increasing and then decreasing. This may be because the cross-linking points formed by the reaction of 2,2'-diallyl bisphenol A (DBA) and 4,4'-diaminodiphenylmethane (MDA) with 4,4'-bismaleimide diphenylmethane (BMI) gradually increase, making the curing reaction of BMI gradually sufficient, improving the thermal stability and mechanical properties of the resin, thereby improving the residual carbon rate of the modified furfural resin for impregnation.

[0047] When it exceeds a certain range, the cross-linking point is sufficient, but the relative content of BMI is reduced, which in turn reduces the residual carbon rate of the modified furfural resin used for impregnation.

[0048] Examples 10-14 Example 10 Based on the preparation method of Example 1, the 4,4'-bismaleimide diphenylmethane in the modifier is replaced with N,N'-m-phenylene bismaleimide, and the other conditions remain unchanged.

[0049] Example 11 Based on the preparation method of Example 1, the 2,2'-diallyl bisphenol A in the modifier is replaced with allyl phenol formaldehyde, and the other conditions remain unchanged.

[0050] Example 12 Based on the preparation method of Example 1, the 4,4'-diaminodiphenylmethane in the modifier is replaced with dicyandiamide, and the other conditions remain unchanged.

[0051] Example 13 Based on the preparation method of Example 1, 4,4'-bismaleimide diphenylmethane is replaced by N,N'-m-phenylene bismaleimide, 2,2'-diallyl bisphenol A is replaced by allyl phenol formaldehyde, 4,4'-diaminodiphenylmethane is replaced by dicyandiamide, and other conditions remain unchanged.

[0052] Example 14 is based on the preparation method of Example 13, except that 30 g of the modifier is replaced with 50 g of the modifier, and the other conditions remain unchanged.

[0053] The impregnation modified furfural resins of Examples 10-14 were subjected to the above performance tests, and the test results are shown in Table 3.

[0054] Table 3 Performance test table of Example 1 and Examples 10-14 project Example 1 Example 10 Embodiment 11 Example 12 Example 13 Embodiment 14 Residual carbon rate / % 70.4 68.6 69.4 69.8 66.3 67.8 Referring to Table 3, by comparing Example 1 with Examples 10-14, it can be seen that the modified furfural resin used for impregnation has the highest carbon residue rate and the best effect when the modifier is a mixture of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane.

[0055] Examples 15-20 In Examples 15-20, based on the preparation method of Example 1, the temperature and time of the melting reaction when preparing the modifier are adjusted. The specific adjustments are shown in Table 4.

[0056] The impregnation modified furfural resins of Examples 15-20 were subjected to the above performance tests, and the test results are shown in Table 4 respectively.

[0057] Table 4 Melting reaction temperature and time and performance test table of Example 1 and Examples 15-20 Referring to Table 4, it can be seen from the comparison between Example 1 and Examples 15-20 that as the temperature of the melt reaction increases, the residual carbon rate shows a trend of first increasing and then decreasing. This may be due to the continuous increase in temperature, which promotes the melt reaction to be gradually sufficient, thereby increasing the residual carbon rate of the modified furfural ketone resin for impregnation. When exceeding a certain range, the reactants may be thermally degraded, resulting in a decrease in the performance of the modifier, thereby reducing the residual carbon rate of the modified furfural ketone resin for impregnation.

[0058] As the reaction time of the melting reaction continued to increase, the residual carbon rate showed a trend of gradually increasing and then tending to a stable state. This may be because the reactants were gradually fully melted, thereby increasing the residual carbon rate of the modified furfural resin for impregnation.

[0059] Examples 21-26 In Examples 21-26, based on the preparation method of Example 1, the temperature and time of the heating reaction when preparing the modified furfural resin for impregnation were adjusted. The specific adjustments are shown in Table 5.

[0060] The impregnation modified furfural resins of Examples 21-26 were subjected to the above performance tests, and the test results are shown in Table 5, respectively.

[0061] Table 5 Heating reaction temperature and time and performance test table of Example 1 and Examples 21-26 Referring to Table 5, it can be seen from the comparison between Example 1 and Examples 21-26 that as the temperature of the heating reaction increases, the residual carbon rate shows a trend of first increasing and then decreasing. This may be due to the continuous increase in temperature, which promotes the heating reaction to be gradually sufficient, thereby increasing the residual carbon rate of the modified furfural ketone resin for impregnation. When exceeding a certain range, the reactants may be thermally degraded, resulting in a decrease in the performance of the modified furfural ketone resin for impregnation, thereby reducing the residual carbon rate of the modified furfural ketone resin for impregnation.

[0062] As the reaction time of the heating reaction continued to increase, the residual carbon rate showed a trend of gradually increasing and then tending to a stable state. This may be because the reactants were gradually heated up, thereby increasing the residual carbon rate of the modified furfural ketone resin for impregnation.

[0063] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A modified furfural resin for impregnation, characterized in that The invention comprises the following components in parts by weight: 100 parts of furfural resin and 5-50 parts of a modifier; the modifier is a mixture of bismaleimide, an allyl compound and an organic diamine; The bismaleimide comprises at least one of 4,4'-bismaleimide diphenylmethane and N,N'-m-phenylene bismaleimide; The allyl compound includes at least one of 2,2'-diallyl bisphenol A and allyl phenol formaldehyde; The organic diamine includes at least one of 4,4'-diaminodiphenylmethane and dicyandiamide.

2. The modified furfural resin for impregnation according to claim 1, characterized in that: The modifier is a mixture of 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane.

3. The modified furfural resin for impregnation according to claim 2, characterized in that: The molar ratio of the 4,4'-bismaleimide diphenylmethane, 2,2'-diallyl bisphenol A and 4,4'-diaminodiphenylmethane is 1:(1-5):(1-5).

4. The modified furfural resin for impregnation according to claim 3, characterized in that: The mass ratio of the furfural resin to the modifier is 100:5-30.

5. The modified furfural resin for impregnation according to claim 1, characterized in that: The preparation method of the modifier comprises the following steps: The modified agent is obtained by mixing the bismaleimide, the allyl compound and the organic diamine in the formula amount and then performing a melting reaction.

6. The modified furfural resin for impregnation according to claim 5, characterized in that: The reaction temperature of the melt reaction is 70-180° C., and the reaction time is 1-5 hours.

7. The method for preparing the modified furfural resin for impregnation according to any one of claims 1 to 6, characterized in that: The furfural resin and the modifier in the formula amount are mixed and heated to react to obtain the modified furfural resin for impregnation.

8. The method for preparing the modified furfural resin for impregnation according to claim 7, characterized in that: The reaction temperature of the heating reaction is 70-150° C., and the reaction time is 1-5 h.

9. An application of a modified furfural resin for impregnation, characterized in that: The modified furfural resin for impregnation as described in any one of claims 1 to 6 is used in the impregnation and densification of carbon-carbon composite materials.

Images