Fiber-reinforced vinyl ester resin composite material and preparation method thereof

Abstract

The invention relates to the technical field of composite materials, and discloses a fiber-reinforced vinyl ester resin composite material and a preparation method thereof.The composite material is prepared by mixing vinyl ester resin serving as a main raw material with modified sepiolite fiber-reinforced additives and the like serving as auxiliary materials. The modified sepiolite fiber reinforced additive is sepiolite fiber of which the surface is modified with a multi-element high-molecular phosphorus-containing flame retardant, and the multi-element high-molecular phosphorus-containing flame retardant equivalently generates a'transition 'structure between the sepiolite fiber and vinyl ester resin, so that the sepiolite fiber can efficiently exert own reinforcing and modifying advantages; the structure of the multi-element high-molecular phosphorus-containing flame retardant contains a large number of triazine rings and phosphorus-containing flame-retardant mechanisms, so that an expanded carbon layer can be quickly formed during combustion of the composite material, oxygen and heat can be isolated, combustion cannot be continued, and the flame-retardant property of the composite material can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a fiber-reinforced vinyl ester resin composite material and a preparation method thereof. Background Art

[0002] Vinyl ester resin is a resin made by ring-opening esterification of epoxy resin and methacrylic acid or acrylic acid. The two ends of its molecular structure contain vinyl groups, and the middle skeleton is epoxy resin. Common raw materials include bisphenol A epoxy (MFE series) or novolac epoxy (W series) reacting with methacrylic acid or acrylic acid. During the reaction, the epoxy group of epoxy resin reacts with unsaturated organic monocarboxylic acid (usually acrylic acid and methacrylic acid) to form unsaturated ester compounds with vinyl groups. The main chain structure of vinyl ester resin determines its unique properties. The matrix of the molecular structure is the epoxy skeleton, which inherits the advantages of epoxy resin, such as excellent chemical resistance, and is suitable for making various corrosion-resistant integral FRP products, corrosion-resistant FRP protective layers on the surface of metal structures and concrete structures, and various acid-, alkali-, and salt-resistant FRP pipes, storage tanks or equipment linings.

[0003] However, it is found in the continuous application process that the mechanical strength of vinyl ester resin is gradually unable to meet the needs of some industries, and it is a flammable material itself, which has certain risks of use. Therefore, the modification of vinyl ester resin is of great significance for its further development and application, among which fiber reinforcement is one of the effective means to improve the performance of vinyl ester resin. Fiber reinforcement can improve the comprehensive properties of composite materials such as mechanical properties by adding fibers to vinyl ester resin. However, there is an interface incompatibility problem between inorganic fiber reinforcement and vinyl ester resin, which is easy to produce phase separation, and then has a greater negative impact on the performance of the resin. In addition, adding inorganic fiber alone cannot significantly improve the flame retardant properties of vinyl ester resin. Therefore, the present invention provides a fiber-reinforced vinyl ester resin composite material, which can solve the problems existing in the prior art. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides a fiber-reinforced vinyl ester resin composite material and a preparation method thereof.

[0006] (II) Technical solution

[0007] A method for preparing a fiber-reinforced vinyl ester resin composite material, wherein the composite material is made from the following raw materials in parts by weight:

[0008]

[0009] The preparation method comprises the following steps:

[0010] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0011] The second step is to add bisphenol A vinyl ester resin and modified sepiolite fiber reinforcement additive into a mixer, start stirring, and after mechanical mixing, add antioxidant, accelerator and initiator into the mixer, stir and mix to form a premix;

[0012] The third step is to pour the premix into the mold, vacuum defoam for 3-5 minutes, raise the temperature to 80-100°C, and maintain it at this temperature for 12-24 hours. Then take it out to obtain the composite material.

[0013] As a further solution of the present invention, the specific preparation method of the modified sepiolite fiber reinforcement additive comprises the following steps:

[0014] Step S1, using toluene diisocyanate to perform surface modification on the acidified sepiolite fiber to obtain functionalized modified sepiolite fiber;

[0015] Step S2, using an organic metal tin catalyst for catalysis, in a toluene medium, using a multi-polymer phosphorus-containing flame retardant as a modifier, and further reacting with the modified sepiolite fiber to obtain a modified sepiolite fiber reinforcement additive.

[0016] As a further solution of the present invention, in step S1, the preparation method of the acidified sepiolite fiber is specifically: immersing the sepiolite fiber in a hydrochloric acid solution with a concentration of 1-3 mol / L, stirring at room temperature for 2-4 hours, separating the fiber material, and washing and drying it.

[0017] As a further embodiment of the present invention, in step S2, the organic metal tin catalyst is any one of dibutyltin diacetate, dibutyltin dilaurate or stannous octoate.

[0018] In the above technical scheme, the sepiolite fiber is firstly subjected to an acidification treatment to create favorable conditions for the next step of organic modification, and then the sepiolite fiber is surface-modified using toluene diisocyanate to produce highly active isocyanate substituents on the surface of the sepiolite fiber to obtain functionalized modified sepiolite fiber, and then under the catalytic action of an organic metal tin catalyst, the isocyanate group can further react with the active hydroxyl substituent in the structure of the multi-polymer phosphorus-containing flame retardant to undergo an amine esterification reaction, thereby coating a large amount of multi-polymer phosphorus-containing flame retardant molecular chains on the surface of the sepiolite fiber to obtain a modified sepiolite fiber reinforcement additive.

[0019] As a further solution of the present invention, in step S2, the specific preparation method of the multi-polymer phosphorus-containing flame retardant comprises the following steps:

[0020] Step SS1, L-malic acid, phosphorus oxychloride-type phosphorus-containing derivatives and tetrahydrofuran are stirred and mixed to form a uniform reaction solution, nitrogen is introduced, and triethylamine is added to the reaction solution. After the addition is completed, the heating rate is controlled to be 2-4°C / min, and the temperature is raised to 60-70°C. After keeping the temperature for 3-6 hours, the nitrogen is removed, and the material is discharged to obtain a phosphorus-containing chain extender;

[0021] Step SS2, add N,N-dimethylformamide and 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione in sequence to a polymerization kettle filled with nitrogen, start stirring, and after a homogeneous reaction liquid is formed, add the phosphorus-containing chain extender to the polymerization kettle, and add a phase transfer catalyst, then increase the temperature to 70-80°C, after chain extension polymerization for 12-18 hours, evaporate and remove the solvent, collect the material, and obtain a multi-polymer phosphorus-containing flame retardant.

[0022] As a further embodiment of the present invention, in step SS1, the phosphorus oxychloride-based phosphorus-containing derivative is any one of dibenzylphosphoryl chloride, 2-chloro-2-oxo-1,3,2-dioxaphospholane or dimethyl chlorophosphate.

[0023] As a further embodiment of the present invention, in step SS2, the molar ratio of the 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione to the phosphorus-containing chain extender is 1:1-1.2.

[0024] As a further embodiment of the present invention, in step SS2, the phase transfer catalyst is any one of tetrabutylammonium hydrogen sulfate, tetramethylammonium chloride or tetrabutylammonium bromide.

[0025] Specifically, in step SS1, triethylamine is used to catalyze the reaction of the active hydroxyl group of the L-malic acid structure with the P-Cl in the structure of the phosphorus-containing derivative of the phosphorus oxychloride type, thereby obtaining a phosphorus-containing chain extender containing two equivalents of carboxyl substituents. In step SS2, a phase transfer catalyst is used to catalyze the continuous ring-opening esterification reaction between the epoxy group in the 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione structure and the phosphorus-containing chain extender, thereby forming a polymerized multi-polymer phosphorus-containing flame retardant.

[0026] As a further embodiment of the present invention, the antioxidant is antioxidant 1010 or antioxidant 168; the accelerator is cobalt isooctanoate; and the initiator is a peroxide initiator.

[0027] A fiber-reinforced vinyl ester resin composite material is prepared by adopting the preparation method.

[0028] (III) Beneficial technical effects

[0029] The present invention prepares a multi-polymer phosphorus-containing flame retardant to modify the surface of sepiolite fiber. On the one hand, the multi-polymer phosphorus-containing flame retardant is equivalent to generating a "transition" structure between the sepiolite fiber and the vinyl ester resin, which promotes the generation of good interface bonding force between each other and improves the compatibility between each other, thereby enabling the sepiolite fiber to effectively exert its own enhanced modification advantages and bear most of the external force, thereby improving the bearing capacity of the composite material. On the other hand, the multi-polymer phosphorus-containing flame retardant structure contains a large number of triazine rings and phosphorus-containing flame retardant mechanisms, which can quickly form an expanded carbon layer when the composite material burns. This dense expanded carbon layer can effectively isolate oxygen and heat, so that the combustion cannot continue to the inside of the composite material, thereby effectively improving the flame retardant properties of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0031] Figure 1 This is the infrared analysis test diagram of the multi-polymer phosphorus-containing flame retardant. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more fully below. Preferred embodiments of the present invention are given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Preparation Example 1

[0034] Preparation of modified sepiolite fiber reinforcement additives:

[0035] Step S1, immersing the sepiolite fiber in a hydrochloric acid solution with a concentration of 2 mol / L, stirring at room temperature for 3 hours, separating the fiber material, and washing and drying the fiber material;

[0036] Step S2, dispersing 2.4 g of sepiolite fiber in 1,4-dioxane, ultrasonicating to form a uniform dispersion, adding 6 g of toluene-2,4-diisocyanate to the dispersion, and then raising the temperature to 80° C. and heat-treating for 5 hours to obtain functionalized modified sepiolite fiber;

[0037] 0.3 g of functionalized modified sepiolite fiber was taken as a test sample, and the sample was titrated according to the hydrochloric acid-di-n-butylamine titration test method. The test results showed that the percentage of isocyanate in the sample was 7.59%;

[0038] Step S3, ultrasonically disperse 1.6 g of modified sepiolite fiber in toluene, then add 5 g of multi-polymer phosphorus-containing flame retardant and 0.1 g of dibutyltin dilaurate, after the addition, raise the temperature to 65°C, keep stirring under nitrogen protection for 8 hours, and obtain the modified sepiolite fiber reinforcement additive.

[0039] Similar to step S2, the same weight of modified sepiolite fiber reinforcement additive was weighed for hydrochloric acid-di-n-butylamine titration test. The result showed that the isocyanate content of the sample was 1.44%, indicating that the isocyanate group of the modified sepiolite fiber was consumed during the reaction with the multi-polymer phosphorus-containing flame retardant.

[0040] The preparation method of the multi-polymer phosphorus-containing flame retardant comprises the following steps:

[0041] Step SS1, 0.6 g of L-malic acid, 0.64 g of 2-chloro-2-oxo-1,3,2-dioxaphospholane and tetrahydrofuran were stirred and mixed to form a uniform reaction solution, nitrogen was introduced, and 0.1 g of triethylamine was added to the reaction solution. After the addition, the heating rate was controlled to be 2°C / min, and the temperature was raised to 70°C. After keeping the temperature for 4 hours, the nitrogen was removed, and the material was discharged to obtain a phosphorus-containing chain extender;

[0042] Step SS2, to a polymerization kettle filled with nitrogen, add N,N-dimethylformamide and 0.4 g of 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione in sequence, start stirring, and after a homogeneous reaction liquid is formed, add 0.35 g of a phosphorus-containing chain extender to the polymerization kettle, and add 0.02 g of tetrabutylammonium bromide, then raise the temperature to 75°C, and after chain extension polymerization for 16 hours, evaporate and remove the solvent, collect the material, and obtain a multi-polymer phosphorus-containing flame retardant.

[0043] The multi-polymer phosphorus-containing flame retardant was made into potassium bromide tablets and subjected to infrared analysis tests. The results are shown in Figure 1 , of which 3272cm -1 The characteristic absorption peak at 3020cm is the characteristic absorption peak of hydroxyl group produced in the ring-opening esterification reaction.-1 The characteristic absorption peak at 1700 cm is the carbon-hydrogen absorption peak of the unsaturated olefinic substituent. -1 ~1800cm -1 The characteristic absorption peaks at 1676 cm are the C=O characteristic absorption peaks of the ester group and the carboxyl group in the excessive phosphorus-containing chain extender structure. -1 The characteristic absorption peak at 1203 cm is the C=O characteristic absorption peak in the triazine ring structure. -1 The characteristic absorption peak that appears at is the P=O characteristic absorption peak.

[0044] Example 1

[0045] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0046]

[0047]

[0048] The preparation method of the composite material comprises the following steps:

[0049] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0050] Step 2: Add bisphenol A vinyl ester resin and modified sepiolite fiber reinforcement additive into a mixer, start stirring, and after mechanical mixing, add antioxidant 168, cobalt isooctanoate and butanone peroxide into the mixer, stir and mix to form a premix;

[0051] The third step is to pour the premix into the mold, vacuum defoam for 3 minutes, raise the temperature to 80°C, and maintain it at this temperature for 24 hours. Then take it out to obtain the composite material.

[0052] The preparation method of the modified sepiolite fiber reinforcement additive is as described in Preparation Example 1, and the same is true below.

[0053] Example 2

[0054] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0055]

[0056] The preparation method of the composite material comprises the following steps:

[0057] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0058] Step 2: Add bisphenol A vinyl ester resin and modified sepiolite fiber reinforcement additive into a mixer, start stirring, and after mechanical mixing, add antioxidant 1010, cobalt isooctanoate and butanone peroxide into the mixer, stir and mix to form a premix;

[0059] The third step is to pour the premix into the mold, vacuum defoam for 4 minutes, raise the temperature to 90°C, and maintain it at this temperature for 18 hours. Then take it out to obtain the composite material.

[0060] Example 3

[0061] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0062]

[0063] The preparation method of the composite material comprises the following steps:

[0064] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0065] Step 2: Add bisphenol A vinyl ester resin and modified sepiolite fiber reinforcement additive into a mixer, start stirring, and after mechanical mixing, add antioxidant 1010, cobalt isooctanoate and butanone peroxide into the mixer, stir and mix to form a premix;

[0066] The third step is to pour the premix into the mold, vacuum defoam for 5 minutes, raise the temperature to 100°C, and maintain it at this temperature for 12 hours. Then take it out to obtain the composite material.

[0067] Comparative Example 1

[0068] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0069]

[0070] The preparation method of the composite material comprises the following steps:

[0071] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0072] Step 2: Add bisphenol A vinyl ester resin and sepiolite fiber into a mixer, start stirring, and after mechanical mixing, add antioxidant 1010, cobalt isooctanoate and butanone peroxide into the mixer, stir and mix to form a premix;

[0073] The third step is to pour the premix into the mold, vacuum defoam for 4 minutes, raise the temperature to 90°C, and maintain it at this temperature for 18 hours. Then take it out to obtain the composite material.

[0074] Comparative Example 2

[0075] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0076]

[0077] The preparation method of the composite material comprises the following steps:

[0078] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0079] Step 2: Add bisphenol A vinyl ester resin and multi-polymer phosphorus-containing flame retardant into a mixer, start stirring, and after mechanical mixing, add antioxidant 1010, cobalt isooctanoate and butanone peroxide into the mixer, stir and mix to form a premix;

[0080] The third step is to pour the premix into the mold, vacuum defoam for 4 minutes, raise the temperature to 90°C, and maintain it at this temperature for 18 hours. Then take it out to obtain the composite material.

[0081] Comparative Example 3

[0082] A fiber-reinforced vinyl ester resin composite material is made from the following raw materials in parts by weight:

[0083]

[0084]

[0085] The preparation method of the composite material comprises the following steps:

[0086] The first step is to weigh and prepare all the raw materials according to the weight proportions;

[0087] Step 2: Add bisphenol A vinyl ester resin, antioxidant 1010, cobalt isooctanoate and butanone peroxide into a mixer, stir and mix to form a premix;

[0088] The third step is to pour the premix into the mold, vacuum defoam for 4 minutes, raise the temperature to 90°C, and maintain it at this temperature for 18 hours. Then take it out to obtain the composite material.

[0089] Test Case

[0090] The composite materials in the examples and comparative examples were cut into test samples that met the specifications and subjected to the following tests. The results are recorded in Table 1:

[0091] Table 1 - Test results

[0092] Tensile strength / MPa <![CDATA[Impact strength / kJ / m 2 > Bending strength / MPa Limiting oxygen index / % Example 1 83.4 23.4 119.1 32.1 Example 2 84.1 23.8 119.7 32.3 Example 3 83.5 23.3 119.6 31.9 Comparative Example 1 77.9 17.9 108.2 19.8 Comparative Example 2 68.2 14.1 99.7 31.5 Comparative Example 3 60.7 12.6 86.9 19.0

[0093] The reference standard for tensile strength test is GB / T 1040.3-2006; the reference standard for impact strength test is GB / T9341-2008; the reference standard for flexural strength test is GB / T 1843-2008; the reference standard for limiting oxygen index test is GB / T 2406.2-2009.

[0094] Based on the ideal embodiment of the present invention, through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a fiber-reinforced vinyl ester resin composite material, characterized in that: The composite material is made of the following raw materials in parts by weight: The preparation method comprises the following steps: The first step is to weigh and prepare all the raw materials according to the weight proportions; The second step is to add bisphenol A vinyl ester resin and modified sepiolite fiber reinforcement additive into a mixer, start stirring, and after mechanical mixing, add antioxidant, accelerator and initiator into the mixer, stir and mix to form a premix; The third step is to pour the premix into the mold, vacuum defoam for 3-5 minutes, raise the temperature to 80-100°C, and maintain it at this temperature for 12-24 hours. Then take it out to obtain the composite material.

2. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 1, characterized in that: The specific preparation method of the modified sepiolite fiber reinforcement additive comprises the following steps: Step S1, using toluene diisocyanate to perform surface modification on the acidified sepiolite fiber to obtain functionalized modified sepiolite fiber; Step S2, using an organic metal tin catalyst for catalysis, in a toluene medium, using a multi-polymer phosphorus-containing flame retardant as a modifier, and further reacting with the modified sepiolite fiber to obtain a modified sepiolite fiber reinforcement additive.

3. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 2, characterized in that: In step S1, the preparation method of the acidified sepiolite fiber is specifically as follows: immersing the sepiolite fiber in a hydrochloric acid solution with a concentration of 1-3 mol / L, stirring at room temperature for 2-4 hours, separating the fiber material, and washing and drying the fiber material.

4. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 2, characterized in that: In step S2, the organic metal tin catalyst is any one of dibutyltin diacetate, dibutyltin dilaurate or stannous octoate.

5. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 2, characterized in that: In step S2, the specific preparation method of the multi-polymer phosphorus-containing flame retardant comprises the following steps: Step SS1, L-malic acid, phosphorus oxychloride-type phosphorus-containing derivatives and tetrahydrofuran are stirred and mixed to form a uniform reaction solution, nitrogen is introduced, and triethylamine is added to the reaction solution. After the addition is completed, the heating rate is controlled to be 2-4°C / min, and the temperature is raised to 60-70°C. After keeping the temperature for 3-6 hours, the nitrogen is removed, and the material is discharged to obtain a phosphorus-containing chain extender; Step SS2, add N,N-dimethylformamide and 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione in sequence to a polymerization kettle filled with nitrogen, start stirring, and after a homogeneous reaction liquid is formed, add the phosphorus-containing chain extender to the polymerization kettle, and add a phase transfer catalyst, then increase the temperature to 70-80°C, after chain extension polymerization for 12-18 hours, evaporate and remove the solvent, collect the material, and obtain a multi-polymer phosphorus-containing flame retardant.

6. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 5, characterized in that: In step SS1, the phosphorus oxychloride-based phosphorus-containing derivative is any one of dibenzyl phosphorus oxychloride, 2-chloro-2-oxo-1,3,2-dioxaphospholane or dimethyl chlorophosphate.

7. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 5, characterized in that: In step SS2, the molar ratio of the 1,3-bis(oxiranylmethyl)-5-(2-propenyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione to the phosphorus-containing chain extender is 1:1-1.

2.

8. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 5, characterized in that: In step SS2, the phase transfer catalyst is any one of tetrabutylammonium hydrogen sulfate, tetramethylammonium chloride or tetrabutylammonium bromide.

9. The method for preparing a fiber-reinforced vinyl ester resin composite material according to claim 1, characterized in that: The antioxidant is antioxidant 1010 or antioxidant 168; the accelerator is cobalt isooctanoate; and the initiator is a peroxide initiator.

10. A fiber-reinforced vinyl ester resin composite material as claimed in claim 1, characterized in that: The method is prepared according to any one of claims 1 to 9.

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