High molecular weight phenolic resin fiber and preparation method thereof

Abstract

The invention relates to a high-molecular-weight phenolic resin fiber and a preparation method thereof, and relates to the technical field of phenolic resin fiber preparation. Preparation raw materials comprise the following components in parts by mass: 40-60 parts of organic phosphorus modified phenolic resin, 5-10 parts of a composite etherification modifier, 4-6 parts of potassium hydroxide, 3-5 parts of amination modified nano aluminum oxide, 10-15 parts of bismaleimide and 50-60 parts of polyvinyl butyral. The phenolic resin fiber has the effects of improving the strength, toughness and high temperature resistance of the phenolic resin fiber, and the phenolic resin has good spinnability.

Description

Technical Field

[0001] The present application relates to the technical field of phenolic resin fiber preparation, and particularly relates to a high molecular weight phenolic resin fiber and a preparation method thereof. Background Art

[0002] Due to properties such as flame prevention, fire resistance, heat insulation, and corrosion resistance, phenolic fibers can be used as heat insulation, insulation, and corrosion-resistant materials in space navigation, national defense, and the aviation industry, and can also be used as fireproof and corrosion-proof clothing and acid- and corrosion-resistant filter materials. At the same time, it is also the primary raw material for special fibers such as carbon fibers, graphite fibers, activated carbon fibers, and ion exchange.

[0003] Phenolic fibers are generally prepared by melt spinning a thermoplastic phenolic resin to obtain a raw fiber, and then heating and curing in a mixed solution of acid and aldehyde to crosslink into an insoluble and infusible fiber. Due to the too small molecular weight and too short molecular chain of low molecular weight phenolic resin, although the orientation degree is increased by the shearing action of the spinneret hole during melt spinning, it is basically still the stacking of resin molecules. After curing in a very short time, it cannot be drawn again, and the obtained resin raw fiber is very fragile and has extremely low strength. A tiny disturbance can break the raw fiber and prevent continuous spinning, so it needs to be improved. Summary of the Invention

[0004] In order to improve the strength of phenolic resin fibers, the present application provides a high molecular weight phenolic resin fiber and a preparation method thereof.

[0005] The high molecular weight phenolic resin fiber and the preparation method provided by the present application adopt the following technical solutions: In the first aspect, the high molecular weight phenolic resin fiber provided by the present application adopts the following technical solutions: A high molecular weight phenolic resin fiber, the preparation raw materials of which include the following components in parts by mass: 40 - 60 parts of organophosphorus modified phenolic resin 5 - 10 parts of composite etherification modifier 4 - 6 parts of potassium hydroxide 3 - 5 parts of amino-modified nano-aluminum oxide 10 - 15 parts of bismaleimide 50 - 60 parts of polyvinyl butyral.

[0006] The organophosphorus-modified phenolic resin contains phosphorus-based groups, has good compatibility and flame retardancy, and can improve the high-temperature resistance of phenolic resin fibers; the composite etherification modifier reacts with phenolic hydroxyl groups to increase the etherification degree of the phenolic resin, thereby enhancing the reaction performance of the resin, reducing the defects inside the phenolic resin fibers, and improving the strength and toughness of the phenolic resin fibers; bismaleimide contains an imide ring structure and can undergo a copolymerization crosslinking reaction with the etherified phenolic resin, which can toughen the phenolic resin and improve the high-temperature resistance of the resin; the aminated modified nano-aluminum oxide has good dispersibility and compatibility, can promote the uniform reaction curing of phenolic resin fibers, and improve the stability of the phenolic resin; polyvinyl butyral has high tensile strength and good flexibility, can improve the spinning performance of phenolic resin fibers, and enhance the strength and toughness.

[0007] Preferably, the raw materials for preparing the organophosphorus-modified phenolic resin include phenol, formaldehyde, and triphenyl phosphate.

[0008] Triphenyl phosphate is an organophosphorus compound with high-efficiency flame retardancy, good system compatibility, and heat resistance. The phosphorus-oxygen free radicals generated at high temperatures can capture hydrogen free radicals, improving the high-temperature resistance of phenolic resin fibers.

[0009] Preferably, the mass ratio of phenol, formaldehyde, and triphenyl phosphate is 1:0.4:(0.06 - 0.08).

[0010] The organophosphorus-modified phenolic resin prepared according to the above mass ratio has good high-temperature resistance.

[0011] Preferably, the composite etherification modifier includes allyl chloride and propargyl chloride.

[0012] Introducing allyl groups through allyl chloride can improve the reaction activity and high-temperature resistance, making the phenolic resin prone to crosslinking polymerization and improving the strength and toughness of the phenolic resin fibers; the chemical bond formed by the reaction of propargyl chloride with the phenolic resin has a high bond energy, can remain stable at high temperatures and is not easily broken. At the same time, propargyl chloride can increase the crosslinking density of the phenolic resin and improve the stability and high-temperature resistance of the phenolic resin fibers.

[0013] Preferably, the mass ratio of allyl chloride and propargyl chloride is 1:(0.4 - 0.6).

[0014] The phenolic resin fibers prepared according to the above mass ratio have high strength, toughness, and good high-temperature resistance.

[0015] Preferably, the raw materials for preparing the aminated modified nano-aluminum oxide include nano-aluminum oxide, trimethoxysilyl chloride, and hexamethylenediamine.

[0016] Trimethoxychlorosilane improves the dispersibility and compatibility of nano-alumina by reacting with the hydroxyl groups on the surface of nano-alumina, and hexamethylenediamine introduces active amino groups to the surface of nano-alumina to improve the reaction performance, strengthen the defects of phenolic resin, and improve its stability.

[0017] Preferably, the amino-modified nano-alumina is prepared by the following steps: Nano-alumina and trimethoxychlorosilane are mixed and dispersed in anhydrous ethanol, deionized water is added, and the reaction is stirred in a water bath, and then hexamethylenediamine is added, and the reaction is continued by stirring in a water bath. The obtained product solution is filtered, and the obtained solid is washed with anhydrous ethanol, and the washed solid is dried to obtain amino-modified nano-alumina.

[0018] The amino-modified nano-alumina prepared according to the above steps has good reaction performance and dispersibility.

[0019] In a second aspect, the present application provides a method for preparing high molecular weight phenolic resin fibers, using the following technical solution: A method for preparing high molecular weight phenolic resin fibers, comprising the following steps: (1) dispersing an organophosphorus modified phenolic resin and potassium hydroxide in n-butanol to obtain a phenolic resin solution, heating the phenolic resin solution and adding a composite etherification modifier, heating the solution to react after the addition is complete, and removing moisture and unreacted small molecules by vacuuming and reducing pressure to obtain an allyl phenolic resin; (2) adding bismaleimide to the allyl phenolic resin, heating and stirring to react, to obtain a maleimide-modified phenolic resin; adding the maleimide-modified phenolic resin prepared above, amino-modified nano-alumina and polyvinyl butyral to anhydrous ethanol, heating and stirring until uniformly mixed, to obtain a spinning solution; (3) wet spinning the spinning solution, stretching the obtained spinning fibers into fibers through a coagulation bath, and rolling them up after oiling to obtain high molecular weight phenolic resin primary fibers, drying the high molecular weight phenolic resin primary fibers, introducing nitrogen gas, heating them, and then curing them by heat preservation to obtain high molecular weight phenolic resin fibers.

[0020] The phenolic resin fiber prepared according to the above steps has high strength, toughness and good high temperature resistance; the nano-alumina component in the spinning reacts with the acid in the coagulation bath to form partial pores, which enables the polyformaldehyde to diffuse to the internal active sites to react, thereby increasing the cross-linking density of the fiber and thus improving its stability.

[0021] Preferably, the coagulation bath comprises boric acid, paraformaldehyde, sodium sulfate, sulfuric acid and water.

[0022] Preferably, the temperature of the coagulation bath is 30-40° C., and the time for the spinning to stay in the coagulation bath is 20-30 seconds.

[0023] The phenolic resin fiber prepared according to the above conditions has high strength, toughness and good high-temperature resistance.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. The organophosphorus-modified phenolic resin contains phosphorus-based groups, has good compatibility and flame retardancy, and can improve the high-temperature resistance of the phenolic resin fiber; the composite etherification modifier reacts with phenolic hydroxyl groups to increase the etherification degree of the phenolic resin, thereby improving the reaction performance of the resin, reducing the defects inside the phenolic resin fiber, and enhancing the strength and toughness of the phenolic resin fiber; bismaleimide contains an imide ring structure and can undergo a copolymerization cross-linking reaction with the etherified phenolic resin, which can toughen the phenolic resin and improve the high-temperature resistance of the resin; the aminated modified nano-aluminum oxide has good dispersibility and compatibility, can promote the uniform reaction curing of the phenolic resin fiber, and improve the stability of the phenolic resin; polyvinyl butyral has high tensile strength and good flexibility, can improve the spinning performance of the phenolic resin fiber, and enhance the strength and toughness.

[0025] 2. Introducing allyl groups through allyl chloride can improve the reaction activity and high-temperature resistance, make the phenolic resin prone to cross-linking polymerization, and improve the strength and toughness of the phenolic resin fiber; the chemical bond formed by the reaction of propargyl chloride with the phenolic resin has a relatively high bond energy, can remain stable at high temperatures and is not easily broken, and at the same time propargyl chloride can increase the cross-linking density of the phenolic resin and improve the stability and high-temperature resistance of the phenolic resin fiber.

[0026] 3. Trimethoxysilane chloride reacts with the hydroxyl groups on the surface of nano-aluminum oxide to improve the dispersibility and compatibility of nano-aluminum oxide. Hexamethylenediamine introduces active amino groups onto the surface of nano-aluminum oxide to improve the reaction performance, reinforce the defects of the phenolic resin, and improve its stability; the nano-aluminum oxide component in the spinning forms some pores by reacting with acid in the coagulation bath, which can enable paraformaldehyde to diffuse to the internal active sites to react, increase the cross-linking density of the fiber, and thus improve its stability. Specific embodiments

[0027] The embodiments of this application disclose a high-molecular-weight phenolic resin fiber and its preparation method. The raw materials used in this application can be obtained from commercially available raw materials except as otherwise specified. The following further elaborates on this application in combination with embodiments: Raw material description: phenol (CAS No.: 108-95-2), formaldehyde (CAS No.: 50-00-0), oxalic acid (CAS No.: 144-62-7), triphenyl phosphate (CAS No.: 115-86-6), nano-aluminum oxide was purchased from Beijing Decodaojin Technology Co., Ltd., trimethoxysilane chloride (CAS No.: 4668-00-2), hexamethylenediamine (CAS No.: 124-09-4), allyl chloride (CAS No.: 107-05-1), propargyl chloride (CAS No.: 624-65-7), bismaleimide (CAS No.: 13676-54-5), polyvinyl butyral (CAS No.: 148-65-2), with a molecular weight of 1,000,000, phenolic resin (CAS No.: 9003-35-4).

[0028] Example 1 Preparation of organophosphorus-modified phenolic resin Mix and disperse 68.49 kg of phenol, 27.4 kg of formaldehyde and 0.5 kg of oxalic acid, reflux and stir at 100 °C at a speed of 200 rpm for 3 h, then add 4.11 kg of triphenyl phosphate and continue to react for 3 h. After cooling to below 30 °C, organophosphorus-modified phenolic resin is obtained.

[0029] Preparation of amino-modified nano-aluminum oxide Mix and disperse 10 kg of nano-aluminum oxide and 2 kg of trimethoxysilane chloride in absolute ethanol, add 0.3 L of deionized water, stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h, then add 1.48 kg of hexamethylenediamine, and continue to stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h. Filter the resulting product solution, wash the obtained solid with absolute ethanol, and dry the washed solid in an oven at 80 °C to obtain amino-modified nano-aluminum oxide.

[0030] Preparation of high molecular weight phenolic resin fiber Disperse 40 kg of organophosphorus-modified phenolic resin and 4 kg of potassium hydroxide in 50 L of n-butanol to obtain a phenolic resin solution. Heat the phenolic resin solution to 30 °C, add 5 kg of a composite etherification modifier, and the mass ratio of allyl chloride to propargyl chloride in the composite etherification modifier is 1:0.4. Add it all within 2 h. After adding, heat to 80 °C and react for 4 h. Evacuate to reduce pressure to remove water and unreacted small molecule substances to obtain allyl phenolic resin.

[0031] Add 10 kg of bismaleimide to allyl phenolic resin, heat up to 100 °C, and stir and react at a speed of 200 rpm for 1 h to obtain maleimide-modified phenolic resin; add the maleimide-modified phenolic resin prepared above, 3 kg of amino-modified nano-aluminum oxide, and 50 kg of polyvinyl butyral to 500 L of absolute ethanol, and stir at 55 °C until evenly mixed to obtain a spinning solution.

[0032] Perform wet spinning on the spinning solution, stretch the obtained spun fiber through a coagulation bath to form fibers, and wind up after oiling treatment to obtain high molecular weight phenolic resin nascent fibers. The above coagulation bath contains the following components in mass percentage: boric acid 2%, paraformaldehyde 5%, sodium sulfate 30%, sulfuric acid 1%, and the balance is water. The temperature of the coagulation bath is 30 °C, and the residence time of the spinning in the coagulation bath is 30 s; dry the high molecular weight phenolic resin nascent fibers in a vacuum oven at 50 °C for 1 h, then introduce nitrogen, heat up to 180 °C and keep warm for 2 h to obtain high molecular weight phenolic resin fibers.

[0033] Example 2 Prepare organophosphorus-modified phenolic resin Mix and disperse 67.57 kg of phenol, 27.02 kg of formaldehyde, and 0.5 kg of oxalic acid, reflux and stir and react at 100 °C at a speed of 200 rpm for 3 h, then add 5.41 kg of triphenyl phosphate and continue to react for 3 h. After cooling to below 30 °C, obtain organophosphorus-modified phenolic resin.

[0034] Prepare amino-modified nano-aluminum oxide Mix and disperse 10 kg of nano-aluminum oxide and 2 kg of trimethoxysilane chloride in absolute ethanol, add 0.3 L of deionized water, stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h, then add 1.48 kg of hexamethylenediamine, and continue to stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h. Filter the obtained product solution, wash the obtained solid with absolute ethanol, and dry the washed solid in an oven at 80 °C to obtain amino-modified nano-aluminum oxide.

[0035] Prepare high molecular weight phenolic resin fibers Disperse 60 kg of organophosphorus-modified phenolic resin and 6 kg of potassium hydroxide in 50 L of n-butanol to obtain a phenolic resin solution. Heat the phenolic resin solution to 30 °C, add 10 kg of a composite etherification modifier, and the mass ratio of allyl chloride to propargyl chloride in the composite etherification modifier is 1:0.6. Add it within 2 h. After adding, heat up to 80 °C and react for 4 h. Evacuate and reduce pressure to remove water and unreacted small molecule substances to obtain allyl phenolic resin.

[0036] Add 15 kg of bismaleimide to allyl phenolic resin, heat up to 100 °C, stir and react at a speed of 200 rpm for 1 h to obtain maleimide-modified phenolic resin; add the maleimide-modified phenolic resin prepared above, 5 kg of amino-modified nano-aluminum oxide and 60 kg of polyvinyl butyral to 500 L of absolute ethanol, and stir at 55 °C until evenly mixed to obtain a spinning solution.

[0037] Perform wet spinning on the spinning solution, stretch the obtained spun fiber through a coagulation bath to form fibers, and wind up after oiling treatment to obtain nascent high-molecular-weight phenolic resin fibers. The above-mentioned coagulation bath contains the following components in mass percentage: boric acid 2%, paraformaldehyde 5%, sodium sulfate 30%, sulfuric acid 1%, and the balance is water. The temperature of the coagulation bath is 40 °C, and the residence time of the spinning in the coagulation bath is 20 s; dry the nascent high-molecular-weight phenolic resin fibers in a vacuum oven at 50 °C for 1 h, then introduce nitrogen, heat up to 180 °C and keep warm for 2 h to obtain high-molecular-weight phenolic resin fibers.

[0038] Example 3 Prepare organophosphorus-modified phenolic resin Mix and disperse 68.03 kg of phenol, 27.21 kg of formaldehyde and 0.5 kg of oxalic acid, reflux and stir at 100 °C at a speed of 200 rpm for 3 h, then add 4.76 kg of triphenyl phosphate and continue to react for 3 h. After cooling to below 30 °C, obtain organophosphorus-modified phenolic resin.

[0039] Prepare amino-modified nano-aluminum oxide Mix and disperse 10 kg of nano-aluminum oxide and 2 kg of trimethoxysilane chloride in absolute ethanol, add 0.3 L of deionized water, stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h, then add 1.48 kg of hexamethylenediamine, and continue to stir and react at 80 °C in a water bath at a speed of 200 rpm for 4 h. Filter the obtained product solution, wash the obtained solid with absolute ethanol, and dry the washed solid in an oven at 80 °C to obtain amino-modified nano-aluminum oxide.

[0040] Prepare high-molecular-weight phenolic resin fibers Disperse 50 kg of organophosphorus-modified phenolic resin and 5 kg of potassium hydroxide in 50 L of n-butanol to obtain a phenolic resin solution. Heat the phenolic resin solution to 30 °C, add 7.5 kg of a composite etherification modifier, and the mass ratio of allyl chloride to propargyl chloride in the composite etherification modifier is 1:0.5. Add it within 2 h. After adding, heat up to 80 °C and react for 4 h. Evacuate and reduce the pressure to remove water and unreacted small molecules to obtain allyl phenolic resin.

[0041] Add 12.5 kg of bismaleimide to allyl phenolic resin, heat up to 100 °C, and stir and react at a speed of 200 rpm for 1 h to obtain maleimide-modified phenolic resin; add the maleimide-modified phenolic resin prepared above, 4 kg of amino-modified nano-aluminum oxide, and 55 kg of polyvinyl butyral to 500 L of absolute ethanol, and stir at 55 °C until evenly mixed to obtain a spinning solution.

[0042] Perform wet spinning on the spinning solution, stretch the obtained spun fiber through a coagulation bath to form fibers, and wind up after oiling treatment to obtain virgin fibers of high molecular weight phenolic resin. The above-mentioned coagulation bath contains the following components in mass percentage: boric acid 2%, paraformaldehyde 5%, sodium sulfate 30%, sulfuric acid 1%, and the balance is water. The temperature of the coagulation bath is 35 °C, and the residence time of the spinning in the coagulation bath is 25 s; dry the virgin fibers of high molecular weight phenolic resin in a vacuum oven at 50 °C for 1 h, then introduce nitrogen, heat up to 180 °C and keep warm for 2 h to obtain high molecular weight phenolic resin fibers.

[0043] Example 4 Example 4 is based on Example 3. The difference between Example 4 and Example 3 is only that the dosage of phenol in Example 4 is 69.44 kg, the dosage of formaldehyde is 27.78 kg, and the dosage of triphenyl phosphate is 2.78 kg.

[0044] Example 5 Example 5 is based on Example 3. The difference between Example 5 and Example 3 is only that the dosage of phenol in Example 5 is 66.67 kg, the dosage of formaldehyde is 26.67 kg, and the dosage of triphenyl phosphate is 6.66 kg.

[0045] Example 6 Example 6 is based on Example 3. The difference between Example 6 and Example 3 is only that the mass ratio of allyl chloride to propargyl chloride in Example 6 is 1:0.3.

[0046] Example 7 Example 7 is based on Example 3. The difference between Example 7 and Example 3 is only that the mass ratio of allyl chloride to propargyl chloride in Example 7 is 1:0.7.

[0047] Example 8 Example 8 is based on Example 3. The difference between Example 8 and Example 3 is only that the composite etherification modifier in Example 8 is replaced by allyl chloride.

[0048] Example 9 Example 9 is based on Example 3. The difference between Example 9 and Example 3 is only that the composite etherification modifier in Example 9 is replaced by propargyl chloride.

[0049] Example 10 Example 10 is based on Example 3. The only difference between Example 10 and Example 3 is that trimethoxysilane chloride is not added when preparing amino-functionalized nano-aluminum oxide in Example 10.

[0050] Comparative Example 1 Comparative Example 1 is based on Example 3. The only difference between Comparative Example 1 and Example 3 is that the organophosphorus-modified phenolic resin is replaced with phenolic resin in Comparative Example 1.

[0051] Comparative Example 2 Comparative Example 2 is based on Example 3. The only difference between Comparative Example 2 and Example 3 is that the composite etherification modifier is not added in Comparative Example 2.

[0052] Comparative Example 3 Comparative Example 3 is based on Example 3. The only difference between Comparative Example 3 and Example 3 is that the amino-functionalized modified nano-aluminum oxide is replaced with nano-aluminum oxide in Comparative Example 3.

[0053] Comparative Example 4 Comparative Example 4 is based on Example 3. The only difference between Comparative Example 4 and Example 3 is that bismaleimide is not added in Comparative Example 4.

[0054] Comparative Example 5 Comparative Example 5 is based on Example 3. The only difference between Comparative Example 5 and Example 3 is that polyvinyl butyral is not added in Comparative Example 5.

[0055] Performance detection test (1) Select "Test Method for Tensile Properties of Plastic Films (GB / T 13022 - 1991)" as the standard. Place the specimen in the fixture and test the tensile strength and elongation at break of the specimen. Prepare three samples for each specimen and take the average value after measurement. The results are recorded in Table 1.

[0056] (2) Residual carbon rate detection: Test the residual carbon rate of the specimen at 800 °C in a nitrogen atmosphere. Prepare three samples for each specimen and take the average value after measurement. The results are recorded in Table 1.

[0057] Table 1 Detection results of molecular weight, strength and high temperature resistance of phenolic resin fibers Test Results Tensile Strength (MPa) Elongation at Break (%) Residual Carbon Rate (%) Example 1 232 8.72 73.5 Example 2 238 8.88 74.1 Example 3 245 9.13 74.4 Example 4 225 8.56 71.6 Example 5 228 8.63 72.3 Example 6 221 8.35 70.6 Example 7 234 8.69 72.3 Example 8 208 7.92 68.9 Example 9 211 8.06 65.3 Example 10 218 8.15 70.3 Comparative Example 1 185 6.84 56.7 Comparative Example 2 152 5.67 51.4 Comparative Example 3 194 6.95 60.1 Comparative Example 4 135 4.85 65.7 Comparative Example 5 123 4.17 68.2 As can be seen from Table 1, the tensile strength of Examples 1 - 3 is greater than 232 MPa, the elongation at break is greater than 8.72%, and the residual carbon rate is greater than 73.5%. It can be seen that the phenolic resin fibers prepared in this application have high strength, toughness and good high temperature resistance.

[0058] As can be seen from Table 1, the differences between Examples 4 and 5 and Example 3 are only as follows: in Example 4, the mass ratio of phenol, formaldehyde and triphenyl phosphate is 1:0.4:0.04; in Example 5, the mass ratio of phenol, formaldehyde and triphenyl phosphate is 1:0.4:0.1. Compared with Example 3, the strength, toughness and high-temperature resistance of Examples 4 and 5 are all decreased. This is because the mass ratio of phenol, formaldehyde and triphenyl phosphate is not within the limited range, and too much or too little triphenyl phosphate will affect the stability of the organophosphorus-modified phenolic resin, and further affect its high-temperature resistance, strength and toughness.

[0059] As can be seen from Table 1, the differences between Examples 6 and 7 and Example 3 are only as follows: in Example 6, the mass ratio of allyl chloride and propargyl chloride is 1:0.3; in Example 7, the mass ratio of allyl chloride and propargyl chloride is 1:0.7. Compared with Example 3, the strength, toughness and high-temperature resistance of Examples 6 and 7 are all decreased. This is because the mass ratio of allyl chloride and propargyl chloride is not within the limited range, and too much or too little propargyl chloride will affect the reaction performance and stability of the phenolic resin, so the strength, toughness and high-temperature resistance are all decreased.

[0060] As can be seen from Table 1, the differences between Examples 8 and 9 and Example 3 are only as follows: in Example 8, the composite etherification modifier is replaced by allyl chloride; in Example 9, the composite etherification modifier is replaced by propargyl chloride. Compared with Example 3, the strength, toughness and high-temperature resistance of Examples 8 and 9 are all decreased. This is because the absence of allyl chloride or propargyl chloride will affect the cross-linking reaction performance and stability of the phenolic resin, and the phenolic resin is more likely to break the bonds at high temperatures, so the strength, toughness and high-temperature resistance are all decreased.

[0061] As can be seen from Table 1, the difference between Example 10 and Example 3 is only as follows: in Example 10, trimethoxysilane chloride is not added when preparing amino-functionalized nano-alumina. Compared with Example 3, the strength, toughness and high-temperature resistance of Example 10 are all decreased. This is because without adding trimethoxysilane chloride, the reactivity and dispersibility of nano-alumina are decreased, the effect of amino-functionalization modification is reduced, so the uniformity during pore formation is decreased, the cross-linking degree is high in some regions and low in some regions, and the homogeneity is decreased, thus the strength, toughness and high-temperature resistance are all decreased.

[0062] As can be seen from Table 1, the difference between Comparative Example 1 and Example 3 is only as follows: in Comparative Example 1, the organophosphorus-modified phenolic resin is replaced by phenolic resin. Compared with Example 3, the strength, toughness and high-temperature resistance of Comparative Example 1 are all significantly decreased. This is because when the organophosphorus-modified phenolic resin is replaced by phenolic resin, the lack of organophosphorus modification treatment leads to a decrease in the stability of the phenolic resin, so the strength, toughness and high-temperature resistance are all significantly decreased.

[0063] As can be seen from Table 1, the difference between Comparative Example 2 and Example 3 is only that: in Comparative Example 2, the composite etherification modifier is not added. Compared with Example 3, the strength, toughness and high-temperature resistance of Comparative Example 2 all decrease significantly; this is because the reaction activity of phenolic resin decreases due to the lack of modification treatment with the composite etherification modifier, and the introduction of propargyl is lacking, resulting in a decrease in heat resistance, and thus the strength, toughness and high-temperature resistance all decrease significantly.

[0064] As can be seen from Table 1, the difference between Comparative Example 3 and Example 3 is only that: in Comparative Example 3, the aminated modified nano-alumina is replaced by nano-alumina. Compared with Example 3, the strength, toughness and high-temperature resistance of Comparative Example 3 all decrease significantly; this is because replacing the aminated modified nano-alumina with nano-alumina results in a lack of modification treatment, a decrease in the dispersibility of nano-alumina, and thus a decrease in the uniformity of phenolic resin fibers, a low uniformity of crosslinking reaction in the coagulation bath, and a decrease in the stability of phenolic resin fibers, and thus the strength, toughness and high-temperature resistance all decrease significantly.

[0065] As can be seen from Table 1, the difference between Comparative Example 4 and Example 3 is only that: in Comparative Example 4, bismaleimide is not added. Compared with Example 3, the strength, toughness and high-temperature resistance of Comparative Example 4 all decrease significantly; this is because the lack of bismaleimide for copolymerization crosslinking reaction results in a lack of toughening modification of phenolic resin and a decrease in stability, and thus the strength, toughness and high-temperature resistance all decrease significantly.

[0066] As can be seen from Table 1, the difference between Comparative Example 5 and Example 3 is only that: in Comparative Example 5, polyvinyl butyral is not added. Compared with Example 3, the strength, toughness and high-temperature resistance of Comparative Example 5 all decrease significantly; this is because the lack of polyvinyl butyral results in a decrease in the spinnability of phenolic resin and a reduction in spinning performance, and thus the strength, toughness and high-temperature resistance all decrease significantly.

[0067] This specific embodiment is only an explanation of the present application and does not limit the present application. Through the above description, relevant staff can make various changes and modifications completely within the scope not deviating from the technical idea of this application. The technical scope of this application is not limited to the content in the specification and must be determined according to the scope of the claims.

Claims

1. A high molecular weight phenolic resin fiber, characterized in that: The raw materials for preparation include the following components in parts by weight: 40-60 parts of organic phosphorus modified phenolic resin 5-10 parts of composite etherification modifier Potassium hydroxide 4-6 parts 3-5 parts of amino modified nano alumina Bismaleimide 10-15 parts Polyvinyl butyral 50-60 parts.

2. A high molecular weight phenolic resin fiber according to claim 1, characterized in that: The raw materials for preparing the organic phosphorus modified phenolic resin include phenol, formaldehyde and triphenyl phosphate.

3. A high molecular weight phenolic resin fiber according to claim 2, characterized in that: The mass ratio of the phenol, formaldehyde and triphenyl phosphate is 1:0.4:(0.06-0.08).

4. The high molecular weight phenolic resin fiber according to claim 1, characterized in that: The composite etherification modifier includes allyl chloride and propargyl chloride.

5. A high molecular weight phenolic resin fiber according to claim 4, characterized in that: The mass ratio of allyl chloride to propargyl chloride is 1:(0.4-0.6).

6. The high molecular weight phenolic resin fiber according to claim 1, characterized in that: The raw materials for preparing the amino-modified nano-alumina include nano-alumina, trimethoxychlorosilane and hexamethylenediamine.

7. A high molecular weight phenolic resin fiber according to claim 6, characterized in that: The amino modified nano-alumina is prepared by the following steps: Nano-alumina and trimethoxychlorosilane are mixed and dispersed in anhydrous ethanol, deionized water is added, and the reaction is stirred in a water bath, and then hexamethylenediamine is added, and the reaction is continued by stirring in a water bath. The obtained product solution is filtered, and the obtained solid is washed with anhydrous ethanol, and the washed solid is dried to obtain amino-modified nano-alumina.

8. A method for preparing the high molecular weight phenolic resin fiber as claimed in claim 1, characterized in that: The steps include: (1) dispersing an organophosphorus modified phenolic resin and potassium hydroxide in n-butanol to obtain a phenolic resin solution, heating the phenolic resin solution and adding a composite etherification modifier, heating the solution after the addition is complete to react, and vacuuming and reducing the pressure to remove moisture and unreacted small molecules to obtain an allyl phenolic resin; (2) adding bismaleimide to allyl phenolic resin, heating and stirring to react, to obtain maleimide-modified phenolic resin; adding the maleimide-modified phenolic resin, amino-modified nano-alumina and polyvinyl butyral prepared above to anhydrous ethanol, heating and stirring until uniformly mixed, to obtain a spinning solution; (3) Wet spinning the spinning solution, stretching the obtained spinning fibers into fibers through a coagulation bath, and winding them after oiling to obtain high molecular weight phenolic resin primary fibers, drying the high molecular weight phenolic resin primary fibers, introducing nitrogen gas, heating them, and then curing them by heat preservation to obtain high molecular weight phenolic resin fibers.

9. The method for preparing high molecular weight phenolic resin fiber according to claim 8, characterized in that: The coagulation bath includes boric acid, paraformaldehyde, sodium sulfate, sulfuric acid and water.

10. The method for preparing high molecular weight phenolic resin fiber according to claim 8, characterized in that: The temperature of the coagulation bath is 30-40° C., and the time for the spinning to stay in the coagulation bath is 20-30 seconds.