A basalt fiber reinforced high tear toughness elastomer and its preparation method

Abstract

The present invention relates to a basalt fiber reinforced high tear toughness elastomer and a preparation method thereof, belonging to the technical field of composite materials. The elastomer is based on a nanocomposite gel as a matrix and a basalt fiber plain weave as a reinforcement material. The nanocomposite gel is located on both sides of the basalt fiber plain weave to form a three-layer sandwich structure. The elastomer is formed by pouring a nanocomposite gel prepolymer liquid on both sides of the basalt fiber and then polymerizing it. The prepolymer liquid is composed of propylene-based polymerization monomers, inorganic nanoparticle sol, initiator and catalyst. A basalt fiber reinforced high tear toughness nanocomposite elastomer is prepared by free radical in situ polymerization using the nanocomposite gel as a matrix and the basalt fiber plain weave as a reinforcement material. By means of the high mechanical properties of the nanocomposite gel and its ability to optimize the interface of the basalt fiber material, the elastomer has stronger tear energy and exhibits stronger mechanical properties.

Description

Technical Field

[0001] The invention relates to a basalt fiber reinforced high tear toughness elastomer and a preparation method thereof, belonging to the technical field of composite materials. Background Art

[0002] Basalt fiber is a new type of environmentally friendly silicate fiber, made from natural volcanic basalt, which is drawn through a platinum-rhodium alloy sieve. Basalt fiber possesses physical and mechanical properties similar to those of glass fiber and carbon fiber, making it one of the four high-performance fibers, along with aramid fiber, carbon fiber, and ultra-high molecular weight polyethylene fiber. In recent years, the preparation of basalt fiber and its application in composite materials have made rapid progress. In many fields, basalt fiber's performance has reached or even exceeded that of materials such as aramid fiber and carbon fiber, and is widely used in road and civil engineering, aerospace, military equipment, automobiles, and ships.

[0003] Gel materials have attracted widespread attention for their high tensile properties, high elasticity and softness. The use of traditional organic crosslinkers leads to uneven crosslinking of polymers, lack of an effective energy dissipation matrix under external force, and reduced tensile properties. In order to enhance its strength based on its original properties, ultrafine fibers, fiber fabrics, carbon nanotubes, clays and inorganic nanocomposites have been introduced. These methods effectively promote the dispersion of crosslinking points and strengthen the energy-consuming structure. After immersion, the elastomer absorbs the solvent and turns into a gel. The presence of the crosslinker prevents the elastomer from transforming into a gel, but at a certain crosslinker concentration, the high entanglement of the chain segments can also lead to the same result. Both the crosslinker and the high entanglement can make the polymer hard, and the latter will not make the polymer brittle like the former. There are existing literatures that introduce gel as a matrix into composite materials, showing a synergistic toughening effect (Advanced Materials, 2020, 32(31): 1907180). Considering that gel usually has a high expansion rate in water, the interaction with the reinforcement is weak, which limits the transfer of load from the stress point to the entire composite material. The mechanical properties of multi-component composite materials, especially their crack growth resistance, are greatly affected by the interfacial bonding zone and the area between the matrix and the fiber surface.

[0004] The abundant hydrogen bonds and silanol groups on the surface of basalt fibers make them compatible with many polymer matrices, facilitating the formation of stable and robust interfacial bonds with polymers such as epoxy resins and polyurethane resins, making them suitable for use as reinforcement in fiber-reinforced composites. However, these fiber-reinforced composites exhibit poor crack propagation resistance, making them difficult to adapt to increasingly complex environments. Patent application CN116655260A, previously filed by the inventors, discloses a nanocomposite microgel-based basalt fiber sizing and its preparation method. This method utilizes in-situ free radical polymerization to prepare a nanocomposite hydrogel, followed by a pulverization-swelling method to prepare the nanocomposite microgel. The resulting sizing significantly improves the bundling and mechanical properties of basalt fibers, thereby enhancing the interfacial properties of basalt fiber composites. This method produces basalt fibers with high mechanical properties. However, further research is needed to fully realize their market potential in the preparation of elastomeric materials with high tear resistance. Summary of the Invention

[0005] In view of this, an object of the present invention is to provide a basalt fiber reinforced high tear toughness elastomer and a preparation method thereof.

[0006] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0007] A basalt fiber-reinforced high-tear toughness elastomer, comprising a nanocomposite gel as a matrix and a basalt fiber plain weave as a reinforcement material, wherein the nanocomposite gel is positioned on both sides of the basalt fiber plain weave to form a three-layer sandwich structure; the elastomer is formed by pouring a nanocomposite gel prepolymer solution on both sides of the basalt fiber and then polymerizing the solution; the prepolymer solution comprises an propylene-based polymerization monomer, an inorganic nanoparticle sol, an initiator, and a catalyst.

[0008] Preferably, the propylene polymerization monomer accounts for 50% to 80% of the total mass of the prepolymer liquid, the solid content of the inorganic nanoparticle sol accounts for 1% to 4% of the mass of the propylene polymerization monomer, the solid content of the initiator accounts for 0.005% to 0.02% of the mass of the propylene polymerization monomer, and the solid content of the catalyst accounts for 0.1% to 0.2% of the mass of the propylene polymerization monomer.

[0009] Preferably, the density of the basalt fiber plain weave is 200-600 g / cm 2 , thickness is 0.2~0.6mm.

[0010] Preferably, the thickness of the nanocomposite gel on both sides of the basalt fiber plain weave is 0.4-1 mm.

[0011] Preferably, the acrylic polymerizable monomer is one or more of acrylic acid (AA), acrylamide, 2-hydroxyethyl acrylate (HEA), and N-isopropylacrylamide. More preferably, the acrylic polymerizable monomer is acrylic acid (AA) and 2-hydroxyethyl acrylate (HEA), and the molar proportion of HEA in the acrylic polymerizable monomer is 8% to 15%.

[0012] Preferably, the inorganic nanoparticle sol is an aqueous solution of Al(OH)3 nanoparticle sol and / or Ze(OH)4 nanoparticle sol, and the concentration of the aqueous solution is 2% to 3%.

[0013] Preferably, the initiator is ammonium persulfate and / or potassium persulfate.

[0014] Preferably, the catalyst is N,N,N',N'-tetramethylethylenediamine (TEMED).

[0015] A method for preparing a basalt fiber-reinforced high-tear toughness elastomer according to the present invention comprises the following steps:

[0016] After the propylene polymer monomer and the inorganic nanoparticle sol are evenly mixed, an initiator and a catalyst are added, and the mixture is stirred and mixed to obtain a nanocomposite gel prepolymer solution;

[0017] The basalt fiber plain weave is fixed in a mold, with spaces for prepolymer injection left on both sides. After the prepolymer is injected, polymerization is carried out at 25-70°C for 18-48 hours, and the mold is removed to obtain a basalt fiber reinforced high tear toughness elastomer.

[0018] Preferably, the polymerization is carried out at 30-40° C. for 22-26 hours.

[0019] Beneficial effects

[0020] The present invention uses nanocomposite gel as a matrix and basalt fiber plain weave as a reinforcing material to prepare a basalt fiber-reinforced high-tear toughness nanocomposite elastomer through free radical in-situ polymerization. By leveraging the high mechanical properties of the nanocomposite gel and the ability to optimize the interface of the basalt fiber material, the elastomer has stronger tear energy and exhibits stronger mechanical properties.

[0021] The method of the present invention has simple process, low cost and is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the elastomer preparation process described in Example 1.

[0023] Figure 2 Schematic diagram of the tearing energy of Comparative Example 1, Example 1 and basalt fiber.

[0024] Figure 3 Schematic diagram of the tearing energy change curve of the elastomer described in Examples 1-3.

[0025] Figure 4 This is a schematic diagram of a curve showing the effect of Al(OH)3 concentration on the tearing energy of a composite material provided by an embodiment of the present invention.

[0026] Figure 5 1 is a schematic diagram of a curve showing variation of tear energy with thickness of a composite material provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to specific embodiments.

[0028] Comparative Example 1

[0029] 1.05g of 2-hydroxyethyl acrylate (HEA), 3.95g of acrylic acid (AA), and 3wt% Al(OH)3 nanoparticle sol were weighed into a 20mL vial and magnetically stirred for 20 minutes to form a homogeneous mixed solution. 0.01g of potassium persulfate (KPS) was dissolved in deionized water to form a 0.02wt% solution. 2g of the 0.02wt% KPS solution was added to the vial and stirred for 5 minutes. Finally, 8μL of N,N,N',N'-tetramethylethylenediamine (TEMED) was added and stirred for 2 minutes. The mixture was then polymerized at 35°C for 24 hours to obtain a hydrogel matrix material (denoted as AH70Al3).

[0030] The infrared spectrum analysis test results of the hydrogel matrix material show that a large number of ionic coordination bonds and hydrogen bonds are formed between Al(OH)3 and the polymer.

[0031] Scanning electron microscopy test results of the hydrogel matrix material show that a large number of three-dimensional pore structures exist on the surface of the hydrogel.

[0032] Example 1

[0033] (1) Preparation of polymer reaction solution:

[0034] Weigh 1.05 g of 2-hydroxyethyl acrylate (HEA), 3.95 g of acrylic acid (AA) and 3 wt% (the mass fraction of Al(OH)3 nanoparticle sol solid content to monomer) of Al(OH)3 nanoparticle sol into a 20 mL vial and stir magnetically for 20 min to form a uniform mixed solution. Weigh 0.01 g of potassium persulfate (KPS) and dissolve it in deionized water to form a 0.02 wt% solution. Add 2 g of 0.02 wt% KPS solution into the vial and continue stirring for 5 min. Finally, add 8 μL of N,N,N',N'-tetramethylethylenediamine (TEMED) and stir for 2 min to obtain a prepolymer.

[0035] (2) Preparation of elastomer:

[0036] like Figure 1 As shown in the figure, in order to form a sandwich structure, 0.5mm thick gaskets were placed on both sides of the basalt fiber plain weave and basalt fiber (0.4mm thick) was sandwiched in the middle. Then the prepolymer liquid was injected. To prevent the prepolymer liquid from leaking, the fiber was embedded in a space with a depth of 0.4mm. The prepolymer was polymerized at a constant temperature of 35°C for 24 hours to obtain a basalt fiber reinforced high tear toughness elastomer (denoted as BFRSC).

[0037] The mechanical properties of BFRSC, AH70Al3 and basalt fiber (BF) were tested and the results are as follows Figure 2 As shown in the figure, the maximum fracture strength of BFRSC can reach 12.12MPa, the modulus can reach 23.83MPa, and the tear energy can reach 772.30kJ / m 2 The tearing energy of AH70Al3 and basalt fiber is enhanced by 160.90 times and 40.14 times respectively, showing a significant synergistic toughening effect.

[0038] Example 2

[0039] In this embodiment, the amount of HEA is changed to 0.67 g, the amount of AA is changed to 4.33 g, and the rest is the same as in Example 1.

[0040] Example 3

[0041] In this embodiment, the amount of HEA is changed to 0.32 g, the amount of AA is changed to 4.68 g, and the rest is the same as in Example 1.

[0042] The tearing energy results of the elastomers described in Examples 1-3 are as follows: Figure 3 As shown in the figure, as the molar content of HEA in the monomer increases, the tearing energy of the elastomer also increases, from 435.91 kJ / m 2 Increased to 772.30 kJ / m 2 .

[0043] Example 4

[0044] In this embodiment, the solid content of the Al(OH)3 nanoparticle sol accounts for 1% by mass of the monomer, and the rest is the same as in Example 1.

[0045] Example 5

[0046] In this embodiment, the solid content of the Al(OH)3 nanoparticle sol accounts for 3% of the mass fraction of the monomer, and the rest is the same as in Example 1.

[0047] Example 6

[0048] In this embodiment, the solid content of the Al(OH)3 nanoparticle sol accounts for 4% by mass of the monomer, and the rest is the same as in Example 1.

[0049] The tearing energy results of the elastomers described in Example 1 and Examples 4-5 are as follows: Figure 4 As shown in the figure, when the nanoparticles increase from 1wt% to 3wt%, the tearing energy of the composite material increases from 121.74kJ / m 2 Increased to 772.30kJ / m 2 However, when the nanoparticle content was further increased to 4wt%, the tearing energy decreased to 300.63kJ / m 2 .

[0050] Example 7

[0051] In this embodiment, the thickness of the gaskets on both sides of the basalt fiber fabric is 0.2 mm, the total thickness of the elastomer is 0.8 mm, and the rest is the same as in Example 1.

[0052] Example 8

[0053] In this embodiment, the thickness of the gaskets on both sides of the basalt fiber fabric is 0.3 mm, the total thickness of the elastomer is 1.0 mm, and the rest is the same as in Example 1.

[0054] Example 9

[0055] In this embodiment, the thickness of the gaskets on both sides of the basalt fiber fabric is 0.4 mm, the total thickness of the elastomer is 1.2 mm, and the rest is the same as in Example 1.

[0056] Example 10

[0057] In this embodiment, the thickness of the gaskets on both sides of the basalt fiber fabric is 0.5 mm, the total thickness of the elastomer is 1.4 mm, and the rest is the same as in Example 1.

[0058] Example 11

[0059] In this embodiment, the thickness of the gaskets on both sides of the basalt fiber fabric is 1 mm, the total thickness of the elastomer is 2.4 mm, and the rest is the same as in Example 1.

[0060] The tearing energy results of the elastomers described in Examples 7-11 are as follows Figure 5 As shown in Figure 2, as the thickness of the composite material increases, the tearing energy changes gradually slows down and tends to remain unchanged. When the thickness is 0.8 mm, the tearing energy reaches 494.41 kJ / m 2 When the thickness increases to 1.2mm, the tearing energy is 772.30kJ / m 2 , increased by 0.56 times. Continuing to increase the thickness to 1.4mm and 2.4mm, the tearing energy is 753.72kJ / m 2 and 808.21 kJ / m 2 , the increase rate slows down and approaches a gentle curve. Therefore, it is better to control the thickness of the composite material at around 1.2mm.

[0061] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention shall be deemed to be within the scope of protection of the present invention.

Claims

1. A basalt fiber reinforced high tear toughness elastomer, characterized by: The elastomer uses nanocomposite gel as a matrix and basalt fiber plain weave as a reinforcing material. The nanocomposite gel is located on both sides of the basalt fiber plain weave to form a three-layer sandwich structure. The elastomer is formed by pouring nanocomposite gel prepolymer liquid on both sides of the basalt fiber and then polymerizing it. The prepolymer liquid is composed of propylene-based polymerization monomers, inorganic nanoparticle sol, initiator and catalyst.

2. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The propylene polymerization monomer accounts for 50% to 80% of the total mass of the prepolymer liquid, the solid content of the inorganic nanoparticle sol accounts for 1% to 4% of the mass of the propylene polymerization monomer, the solid content of the initiator accounts for 0.005% to 0.02% of the mass of the propylene polymerization monomer, and the solid content of the catalyst accounts for 0.1% to 0.2% of the mass of the propylene polymerization monomer.

3. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The density of the basalt fiber plain weave is 200~600g / cm 2 , thickness is 0.2~0.6mm.

4. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The thickness of the nanocomposite gel on both sides of the basalt fiber plain weave is 0.4-1 mm respectively.

5. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The acrylic polymer monomer is one or more of acrylic acid, acrylamide, 2-hydroxyethyl acrylate and N-isopropylacrylamide.

6. The basalt fiber reinforced high tear toughness elastomer according to claim 5, characterized in that: The acrylic polymer monomers are acrylic acid and 2-hydroxyethyl acrylate, and the molar proportion of 2-hydroxyethyl acrylate in the acrylic polymer monomers is 8% to 15%.

7. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The inorganic nanoparticle sol is an aqueous solution of Al(OH)3 nanoparticle sol and / or Ze(OH)4 nanoparticle sol, and the concentration of the aqueous solution is 2% to 3%.

8. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The initiator is ammonium persulfate and / or potassium persulfate.

9. The basalt fiber reinforced high tear toughness elastomer according to claim 1, characterized in that: The catalyst is N,N,N',N'-tetramethylethylenediamine.

10. A method for preparing a basalt fiber reinforced high tear toughness elastomer according to any one of claims 1 to 9, characterized in that: The method steps include: After the propylene polymer monomer and the inorganic nanoparticle sol are evenly mixed, an initiator and a catalyst are added, and the mixture is stirred and mixed to obtain a nanocomposite gel prepolymer solution; The basalt fiber plain weave fabric is fixed in a mold, leaving space on both sides for prepolymer injection. After the prepolymer is injected, it is polymerized at 25-70°C for 18-48 hours and demolded to obtain a basalt fiber-reinforced high tear toughness elastomer.

11. The method for preparing a basalt fiber reinforced high tear toughness elastomer according to claim 10, characterized in that: Polymerize at 30~40℃ for 22~26h.

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