Boron-silicon-containing phenolic resin heat prevention and insulation integrated composite material and preparation method thereof

Abstract

The invention discloses a boron-silicon-containing phenolic resin heat prevention and insulation integrated composite material and a preparation method thereof. The method comprises the following steps: step 1, weighing phenol, formaldehyde, 4-hydroxyphenylboronic acid, a reaction solvent and a reaction catalyst according to a ratio, adding the weighed materials into a reaction container, and carrying out reaction polymerization to prepare linear boron-containing phenolic resin; 2, silicon resin is added into the linear boron phenolic resin prepared in the step 1, and boron silicon phenolic resin is prepared through chemical polymerization; and step 3, compounding the boron-silicon phenolic resin prepared in the step 2 with a three-dimensional fiber braided fabric, adding a certain curing catalyst, and performing curing molding to obtain the boron-silicon phenolic resin-containing heat-proof and heat-insulating integrated composite material. The preparation method provided by the invention solves the problem that the boron-silicon phenolic resin and the silicon resin are easy to disperse during co-curing, the prepared boron-silicon phenolic resin has outstanding heat resistance and wide process applicability, and the prepared heat prevention and insulation integrated composite material integrates light weight, high strength and heat prevention and insulation integration, and has obvious advantages in a high-temperature use scene.

Description

Technical Field

[0001] The invention relates to the technical field of resin-based heat-insulating integrated composite materials, and in particular to a boron-silicon-containing phenolic resin heat-insulating integrated composite material. Background Art

[0002] The surface of high-speed aircraft, solid rocket combustion chamber, nozzle and other parts face extremely harsh thermal flow environment during operation. High-performance thermal protection materials are an important guarantee to ensure their safe and reliable operation.

[0003] Resin-based composite materials have the advantages of low density, low cost, high strength, and low thermal conductivity, and have been widely used in various thermal protection materials. Among them, phenolic resin-based composite materials are easy to form a carbon layer at high temperature, have a high carbon residue rate, excellent ablation resistance, and have the advantages of low raw material price and simple molding process. Therefore, phenolic resin and its composite materials are the most commonly used resin-based composite thermal protection materials.

[0004] Phenolic resins are divided into thermosetting resins and thermoplastic resins. Commonly used thermosetting phenolic resins have problems such as high free phenol content, large molecular weight fluctuations, high brittleness after curing, and obvious curing shrinkage, which seriously affect the thermodynamic properties of composite materials. Relatively speaking, the thermoplastic phenolic resin system has a low free phenol content, small molecular weight fluctuations, strong designability, and low curing volume shrinkage.

[0005] As the operating temperature increases, the following deficiencies are exposed in phenolic resin-based composite materials: ① Thermal oxidation weak links such as ether bonds and methylene bridges are formed during the synthesis of phenolic resin, limiting the further improvement of its ablation resistance; ② Gas is released during the carbonization of phenolic resin at high temperature, which reduces the strength and density of the carbon layer, making it extremely easy to peel off during high-speed flight and aerodynamic heating of the aircraft.

[0006] In response to the above problems, the following methods are currently commonly used to modify phenolic resins: ① Improving the heat resistance by increasing the crosslinking degree of the resin, such as replacing phenol and formaldehyde with multifunctional monomers to introduce additional crosslinking sites; ② Introducing a condensed ring structure to increase the carbon content of the resin; ③ Replacing the thermal oxidation weak links in the phenolic resin, improving the heat resistance of phenolic resin by blocking the phenolic hydroxyl groups, replacing or eliminating ether bonds, methylene bridges and other thermal oxidation weak links; ④ Introducing elements with high bond energy and high thermal oxidation stability, such as non-metallic elements B and Si. Summary of the invention

[0007] In order to solve the problem that the high temperature performance of existing phenolic resins and phenolic resin-based composite thermal protection materials decreases and restricts the use limit, the present invention provides a method for preparing a boron-silicon-containing phenolic resin thermal insulation integrated composite material, the method comprising the following steps:

[0008] Step 1, weighing phenol, formaldehyde, 4-hydroxyphenylboric acid, a reaction solvent and a reaction catalyst according to a certain proportion, adding them into a reaction container for polymerization reaction to obtain a linear boron phenolic resin;

[0009] Step 2, adding silicone resin to the linear boron phenolic resin obtained in step 1 to obtain boron silicon phenolic resin through chemical polymerization;

[0010] Step 3, compounding the borosilicate phenolic resin obtained in step 2 with the three-dimensional fiber braid, adding a certain curing catalyst, and curing and molding to obtain a borosilicate phenolic resin-containing heat-insulating integrated composite material.

[0011] Preferably, the ratio in step 1 is 100 parts of phenol, 50 to 80 parts of formaldehyde, 10 to 40 parts of 4-hydroxyphenylboric acid, 50 to 100 parts of reaction solvent and 1 to 5 parts of reaction catalyst.

[0012] Preferably, the reaction solvent in step 1 is one of methanol, ethanol or isopropanol.

[0013] Preferably, the reaction catalyst in step 1 is one or a combination of two of p-toluenesulfonic acid, oxalic acid, malonic acid and formic acid.

[0014] Preferably, the reaction polymerization in step 1 is carried out under condensation reflux conditions with a stirring speed of 50 r / min to 300 r / min, reacting at room temperature for 1 h to 4 h, then heating to 70 ° C to 95 ° C at a heating rate of 1 ° C / min to 2 ° C / min, and condensing reflux reaction for 4 h to 10 h under nitrogen protection to obtain a linear boron phenolic resin.

[0015] Preferably, in step 2, the linear boron phenolic resin is 100 parts and the silicone resin is 10 to 50 parts.

[0016] Preferably, the silicone resin in step 2 is one of methyl silicone resin, phenyl silicone resin and methylphenyl silicone resin.

[0017] Preferably, the chemical polymerization conditions in step 2 are stirring at 80° C. to 100° C. for 1 h to 3 h.

[0018] Preferably, the three-dimensional fiber braid in step 3 is one of a carbon fiber three-dimensional braid, a quartz fiber three-dimensional braid, a high-silica fiber three-dimensional braid, and a carbon fiber / quartz fiber mixed three-dimensional braid.

[0019] Preferably, the curing catalyst in step 3 is hexamethylenetetramine, and the amount used is 0% to 10% by weight of the borosilicate phenolic resin.

[0020] Preferably, the curing molding method in step 3 is preferably compression molding, the curing temperature is 90-120°C for heating for 1h-2h, then pressurized at 0-20MPa, heated at 150°C for 1h, heated at 200°C for 2h, heated at 250°C for 4h, cooled to room temperature and demolded to obtain a boron-silicon phenolic resin anti-insulation integrated composite material.

[0021] The present invention also provides a boron-silicon-containing phenolic resin heat-insulating integrated composite material prepared by the above preparation method.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention creatively uses 4-hydroxyphenylboric acid as a boron source. Compared with the commonly used technical route of introducing boron into phenolic resin in the form of boric acid, the present invention solves the problem that the degree of crosslinking is greatly increased due to the introduction of boric acid, and the process performance and high performance are difficult to meet at the same time. In addition, the present invention can increase the boron content in the resin by adjusting the amount of 4-hydroxyphenylboric acid used.

[0024] (2) The present invention uses silicone resin and linear boron phenolic resin to obtain borosilicate phenolic resin by chemical polymerization. Compared with conventional silicone modified phenolic resin, the boron hydroxyl group forms a chemical bond with the silanol group, and the molecular weight and polarity of the boron phenolic resin and silicone resin are finely regulated to achieve polarity matching between the two to ensure that there is no phase separation during storage and curing. The BO bond energy (773KJ / mol) and Si-O bond energy (443KJ / mol) are significantly improved compared to the CC bond energy (334KJ / mol), so that the prepared borosilicate phenolic resin has high heat resistance and high temperature ablation structural integrity.

[0025] (3) The present invention adopts borosilicate phenolic resin and three-dimensional fiber braided fabric to prepare a resin-based composite material. By adjusting the amount of curing catalyst and the molding method, a borosilicate phenolic resin-containing thermal insulation integrated composite material can be prepared, thereby achieving fine control of mechanical properties, ablation resistance and thermal insulation properties to match the thermal protection requirements of different usage environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions disclosed in the present invention, the following briefly introduces the drawings required to be used in some embodiments disclosed in the present invention. Obviously, the drawings described below are only drawings of some embodiments disclosed in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments disclosed in the present invention, the actual process of the method, etc.

[0027] Figure 1A schematic diagram of a method for preparing a borosilicate phenolic resin heat-insulating integrated composite material provided by the present invention;

[0028] Figure 2 The structure diagram of the linear boron phenolic resin provided by the present invention;

[0029] Figure 3 A schematic diagram of the synthesis of borosilicate phenolic resin provided by the present invention;

[0030] Figure 4 This is a microscopic morphology of the borosilicate phenolic resin heat-insulating integrated composite material after oxyacetylene ablation provided by the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] The present invention provides a method for preparing a boron-silicon-containing phenolic resin heat-insulating integrated composite material. Figure 1 As shown, the specific method is as follows:

[0033] Step 1, weigh phenol, formaldehyde, 4-hydroxyphenylboric acid, a reaction solvent and a reaction catalyst according to a certain proportion, add them into a reaction container for polymerization to obtain a linear boron phenolic resin. The structure of the linear boron phenolic resin is as follows: Figure 2 As shown;

[0034] Step 2, adding silicone resin to the linear boron phenolic resin obtained in step 1, and obtaining boron silicon phenolic resin by chemical polymerization. The synthesis process is as follows: Figure 3 As shown;

[0035] Step 3, compounding the borosilicate phenolic resin obtained in step 2 with the three-dimensional fiber braid, adding a certain curing catalyst, and curing and molding to obtain a borosilicate phenolic resin-containing heat-insulating integrated composite material.

[0036] Implementation Case 1

[0037] Step 1: Weigh 100 parts of phenol, 50 parts of formaldehyde, 10 parts of 4-hydroxyphenylboric acid, 50 parts of ethanol and 1 part of formic acid, and then under condensation reflux conditions, stir at a speed of 50 r / min, react at room temperature for 1 hour, heat to 70°C at a heating rate of 1°C / min, and condense reflux under nitrogen protection for 4 hours to obtain a linear boron phenolic resin.

[0038] Step 2: Weigh 100 parts of the linear boron phenolic resin prepared in step 1 and 10 parts of methyl silicone resin, stir at 80° C. for 1 hour to prepare boron silica phenolic resin.

[0039] Step 3: Compound the borosilicate phenolic resin obtained in step 2 with the carbon fiber three-dimensional braid without adding a curing catalyst, heat at 90°C for 1 hour, then pressurize at 20 MPa, heat at 150°C for 1 hour, heat at 200°C for 2 hours, and heat at 250°C for 4 hours. Cool to room temperature and demold to obtain a borosilicate phenolic resin anti-insulation integrated composite material.

[0040] The properties of the boron-silicon phenolic resin heat-insulating integrated composite material prepared by the above method are shown in Table 1. The microstructure after oxyacetylene ablation is shown in Table 1. Figure 4 (a) shown.

[0041] Table 1 Properties of carbon fiber boron silicon phenolic resin thermal insulation integrated composite materials

[0042]

[0043] Implementation Case 2

[0044] Step 1: Weigh 100 parts of phenol, 65 parts of formaldehyde, 25 parts of 4-hydroxyphenylboric acid, 75 parts of isopropanol and 2.5 parts of malonic acid, and then under condensation reflux conditions, stir at a speed of 175r / min, react at room temperature for 2.5h, heat to 80°C at a heating rate of 2°C / min, and condense reflux under nitrogen protection for 7h to obtain a linear boron phenolic resin.

[0045] Step 2: Weigh 100 parts of the linear boron phenolic resin prepared in step 1 and 30 parts of methylphenyl silicone resin, stir at 90° C. for 2 hours to prepare boron silicate phenolic resin.

[0046] Step 3: Compound the borosilicate phenolic resin obtained in step 2 with the quartz fiber three-dimensional braid, add 5% hexamethylenetetramine, heat at 110°C for 1.5 hours, then pressurize to 10 MPa, heat at 150°C for 1 hour, heat at 200°C for 2 hours, heat at 250°C for 4 hours, cool to room temperature and demold to obtain a borosilicate phenolic resin anti-insulation integrated composite material.

[0047] The properties of the boron-silicon phenolic resin heat-insulating integrated composite material prepared by the above method are shown in Table 2. The microstructure after oxyacetylene ablation is shown in Table 2. Figure 4 (b) as shown.

[0048] Table 2 Properties of Quartz Fiber Borosilicate Phenolic Resin Thermal Insulation Integrated Composite Materials

[0049]

[0050] Implementation Case 3

[0051] Step 1: Weigh 100 parts of phenol, 80 parts of formaldehyde, 40 parts of 4-hydroxyphenylboric acid, 100 parts of isopropanol and 5 parts of p-toluenesulfonic acid, and then under condensation reflux conditions, stir at a speed of 300 r / min, react at room temperature for 4 hours, heat to 95°C at a heating rate of 1°C / min, and condense reflux under nitrogen protection for 10 hours to obtain a linear boron phenolic resin.

[0052] Step 2: Weigh 100 parts of the linear boron phenolic resin prepared in step 1 and 50 parts of phenyl silicone resin, stir at 100° C. for 3 hours to prepare boron silica phenolic resin.

[0053] Step 3: Compound the borosilicate phenolic resin obtained in step 2 with a carbon fiber / quartz fiber mixed three-dimensional braid, add 10% hexamethylenetetramine, heat at 120°C for 2h, then pressurize at 0MPa, heat at 150°C for 1h, heat at 200°C for 2h, heat at 250°C for 4h, cool to room temperature and demold to obtain a borosilicate phenolic resin anti-insulation integrated composite material.

[0054] The properties of the boron-silicon phenolic resin heat-insulating integrated composite material prepared by the above method are shown in Table 3. The microstructure after oxyacetylene ablation is shown in Table 3. Figure 4 (c) as shown.

[0055] Table 3 Properties of carbon fiber / quartz mixed fiber borosilicate phenolic resin thermal insulation integrated composite materials

[0056]

[0057] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention using the above disclosed contents without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the contents of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a boron-silicon-containing phenolic resin heat-insulating integrated composite material, characterized in that: The method comprises the following steps: Step 1, weighing phenol, formaldehyde, 4-hydroxyphenylboric acid, a reaction solvent and a reaction catalyst according to a certain proportion, adding them into a reaction container for polymerization reaction to obtain a linear boron phenolic resin; The ratio is 100 parts of phenol, 50 to 80 parts of formaldehyde, 10 to 40 parts of 4-hydroxyphenylboric acid, 50 to 100 parts of reaction solvent and 1 to 5 parts of reaction catalyst; Step 2, adding silicone resin to the linear boron phenolic resin obtained in step 1 to obtain boron silicon phenolic resin through chemical polymerization; Linear boron phenolic resin is 100 parts, silicone resin is 10-50 parts; Step 3, compounding the borosilicate phenolic resin obtained in step 2 with the three-dimensional fiber braid, adding a certain curing catalyst, and curing and molding to obtain a borosilicate phenolic resin-containing heat-insulating integrated composite material.

2. The preparation method according to claim 1, characterized in that: The reaction solvent in step 1 is one of methanol, ethanol and isopropanol.

3. The preparation method according to claim 1, characterized in that: The reaction catalyst in step 1 is one or a combination of two of p-toluenesulfonic acid, oxalic acid, malonic acid and formic acid.

4. The preparation method according to claim 1, characterized in that: The reaction polymerization in step 1 is carried out under condensation reflux conditions with a stirring speed of 50 r / min to 300 r / min. After reacting at room temperature for 1 h to 4 h, the reaction is heated to 70 ° C to 95 ° C at a heating rate of 1 ° C / min to 2 ° C / min, and condensed reflux is reacted for 4 h to 10 h under nitrogen protection to obtain a linear boron phenolic resin.

5. The preparation method according to claim 1, characterized in that: The silicone resin in step 2 is one of methyl silicone resin, phenyl silicone resin and methylphenyl silicone resin.

6. The preparation method according to claim 1, characterized in that: The chemical polymerization conditions in step 2 are stirring at 80° C. to 100° C. for 1 h to 3 h.

7. The preparation method according to claim 1, characterized in that: The three-dimensional fiber braid in step 3 is one of a carbon fiber three-dimensional braid, a quartz fiber three-dimensional braid, a high-silica fiber three-dimensional braid, and a carbon fiber and quartz fiber mixed three-dimensional braid.

8. The preparation method according to claim 1, characterized in that: The curing catalyst in step 3 is hexamethylenetetramine, and the amount used is 0% to 10% by weight of the borosilicate phenolic resin.

9. The preparation method according to claim 1, characterized in that: The curing molding method described in step 3 is compression molding, the curing temperature is 90℃~120℃ heating for 1h~2h, then pressurizing at 0~20MPa, heating at 150℃ for 1h, heating at 200℃ for 2h, heating at 250℃ for 4h, cooling to room temperature and demolding to obtain boron silicon phenolic resin anti-insulation integrated composite material.

10. A boron-silicon-containing phenolic resin heat-insulating integrated composite material, characterized in that: A boron-silicon-containing phenolic resin heat-insulating integrated composite material prepared by the method according to any one of claims 1 to 9.

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