Ultraviolet radiation resistant PBO fiber sizing agent and preparation method thereof

Abstract

The invention relates to an ultraviolet radiation resistant PBO (poly (p-phenylene benzobisoxazole)) fiber sizing agent and a preparation method thereof, and the sizing agent comprises the following components in parts by weight: 2-10 parts of ultraviolet-resistant nanoparticles, 20-50 parts of epoxy resin main slurry and the balance of water. While the stability of the emulsion type sizing agent is ensured, the emulsion type sizing agent is endowed with better ultraviolet radiation resistance, and the interface performance of a composite material taking the PBO fiber as a reinforcing phase is favorably improved.

Description

Technical Field

[0001] The present invention belongs to the field of material surface treatment and modification, and particularly relates to an ultraviolet radiation-resistant sizing agent for PBO fibers and a preparation method thereof. Background Art

[0002] Poly(p-phenylene benzobisoxazole) (PBO) is a highly conjugated rigid rod-like macromolecule composed of benzene rings and heteroaromatic rings. Due to its unique chemical structure, the PBO fibers obtained by liquid crystal spinning have a series of excellent properties, including high strength and modulus, high temperature resistance, good chemical stability and dimensional stability, strong flame retardancy, etc., and are often used as reinforcements for resin-based composites. Therefore, high-performance PBO fibers can be used to make high-strength ropes and cables, heat-resistant filter materials, heat-resistant and flame-retardant fabrics, etc., and have important applications in aerospace, national defense, and many civilian fields.

[0003] Although PBO fibers are outstanding in many aspects including mechanical properties, their ultraviolet light irradiation resistance is very limited. Even after short-term ultraviolet light irradiation, the mechanical properties of PBO fibers and their composites will be severely reduced, which will lead to a decline in their use safety and stability and a shortening of their service life. This seriously hinders the further development and application of PBO fibers and their composites. Therefore, how to improve the ultraviolet radiation resistance of PBO fibers has become a key problem to be solved urgently.

[0004] The method of coating the surface of PBO fibers with a sizing agent to form an ultraviolet radiation-resistant coating has the advantages of simple operation, no damage to the fibers, and being beneficial to enhancing the bonding strength between the reinforcing fibers and the matrix material in the subsequent preparation of composites, and thus has been widely studied and applied. For example, Chinese Patent CN113293614A discloses a method for preparing a solution-type PBO fiber sizing agent with ultraviolet aging resistance by adding a light absorber and a light stabilizer to an aqueous epoxy resin; Chinese Patent CN104264484A discloses a method for obtaining a Pickering emulsion sizing agent by compounding graphene oxide with a traditional organic emulsifier. However, the emulsion-type PBO fiber sizing agents in the above-mentioned invention patents use conventional organic small molecules or macromolecular emulsifiers. These conventional organic emulsifiers are likely to cause the obtained composites to absorb water, thereby reducing their mechanical properties; at the same time, the addition of organic emulsifiers will lead to a decrease in the interlaminar shear strength of the composites.

[0005] Emulsion sizing agents have become the mainstream in industrial production. At present, there is no relevant report on using ultraviolet-resistant nanoparticles as Pickering emulsifiers to prepare emulsifiers for ultraviolet-irradiation-resistant PBO fibers. Using ultraviolet-resistant nanoparticles to replace traditional organic emulsifiers can not only ensure the smooth preparation and storage / use stability of emulsion sizing agents, but also reduce costs and endow the sizing agents with the function of ultraviolet irradiation resistance. Further, the ultraviolet-resistant nanoparticles in the sizing agent adhere to the surface of PBO fibers, which can increase their roughness, facilitate the improvement of the compatibility between PBO fibers as the reinforcing phase and the resin matrix, and thus improve the properties of the corresponding composites. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an ultraviolet-irradiation-resistant sizing agent for PBO fibers and its preparation method to improve the ultraviolet irradiation resistance and interfacial bonding properties of the corresponding composites.

[0007] The present invention provides an ultraviolet-irradiation-resistant sizing agent for PBO fibers. By weight, the sizing agent comprises 2-10 parts of ultraviolet-resistant nanoparticles, 20-50 parts of epoxy resin main slurry, and the balance is water.

[0008] Preferably, the sizing agent is an oil-in-water Pickering emulsion, and the ultraviolet-resistant nanoparticles are coated on the surface of the epoxy resin.

[0009] Preferably, the ultraviolet-resistant nanoparticles include at least one of titanium dioxide (TiO 2 ), or zinc oxide (ZnO), and their diameter ranges from 200 to 500 nm.

[0010] Preferably, the epoxy resin main slurry includes at least one of epoxy resin E44, epoxy resin E51, and epoxy resin E54.

[0011] Preferably, the water includes deionized water.

[0012] The present invention also provides a preparation method for an ultraviolet-irradiation-resistant sizing agent for PBO fibers, comprising the following steps:

[0013] S1. Disperse the ultraviolet-resistant nanoparticles in water, perform ultrasonic treatment, and then stir to form an aqueous dispersion;

[0014] S2. Inject the epoxy resin main slurry into the aqueous dispersion obtained in step S1 and stir to emulsify and form an oil-in-water Pickering emulsion.

[0015] Preferably, in step S1, the ultrasonic time is 0.5-1.5 h, and the stirring speed is 1500-2000 r / min.

[0016] Preferably, in the step S2, the injection speed of the epoxy resin main slurry is 2-10 mL / min, the stirring speed is 600-3000 r / min, and the stirring time is 0.5-1.5 h.

[0017] The present invention also provides an application of the above ultraviolet-resistant sizing agent for PBO fibers in a sizing process. After diluting the sizing agent with water to a solid content of 2 wt% - 5 wt%, the PBO fibers are sized by an impregnation method.

[0018] Preferably, when sizing the PBO fibers, the sizing time is controlled to be 10-30 s, and after sizing, the PBO fibers are dried at 100-150 °C.

[0019] In the present invention, the ultraviolet-resistant sizing agent for PBO fibers is as Figure 1 shown, with ultraviolet-resistant nanoparticles coated on the surface of the epoxy resin and dispersed in water.

[0020] Beneficial effects

[0021] (1) The present invention uses ultraviolet-resistant nanoparticles to replace traditional amphiphilic organic small molecules or macromolecules as emulsifiers, which not only ensures the stability of the emulsion-type sizing agent but also endows it with better ultraviolet irradiation resistance.

[0022] (2) The present invention uses ultraviolet-resistant nanoparticles to replace traditional amphiphilic organic small molecules or macromolecules as emulsifiers, which is beneficial to improving the interfacial properties of composites with PBO fibers as the reinforcing phase.

[0023] (3) The raw materials of the present invention are easily available and the operation is simple, which is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the ultraviolet-resistant sizing agent for PBO fibers in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The following specific examples are used to further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0026] The raw materials used in the following examples of the present invention are all commercially available products.

[0027] Example 1

[0028] The preparation method of the ultraviolet-resistant sizing agent for PBO fibers in this example is as follows:

[0029] S1. Disperse titanium dioxide (TiO 2 ) nanoparticles (2 parts) with a diameter of 400 nm in water (68 parts), ultrasonically treat for 1 hour, and stir at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0030] S2. Subsequently, inject epoxy resin E44 (30 parts) into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and maintain a stirring speed of 600 - 3000 r / min for 1 hour, thereby emulsifying to form an oil-in-water Pickering emulsion type sizing agent.

[0031] Dilute the above sizing agent with water to a solid content of 2 wt% and place it in an impregnating bath. Immerse PBO fibers in the sizing agent, control the sizing time to 20 s, and dry the fibers at 120 °C after sizing. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the tensile strength retention rate of the sized PBO fibers is 92%.

[0032] Example 2

[0033] The preparation method of the sizing agent for ultraviolet radiation-resistant PBO fibers in this example is as follows:

[0034] S1. Disperse zinc oxide (ZnO) nanoparticles (2 parts) with a diameter of 400 nm in water (68 parts), ultrasonically treat for 1 hour, and stir at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0035] S2. Subsequently, inject epoxy resin E44 (30 parts) into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and maintain a stirring speed of 600 - 3000 r / min for 1 hour, thereby emulsifying to form an oil-in-water Pickering emulsion type sizing agent.

[0036] Dilute the above sizing agent with water to a solid content of 2 wt% and place it in an impregnating bath. Immerse PBO fibers in the sizing agent, control the sizing time to 20 s, and dry the fibers at 120 °C after sizing. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the tensile strength retention rate of the sized PBO fibers is 91%.

[0037] Example 3

[0038] The preparation method of the sizing agent for ultraviolet radiation-resistant PBO fibers in this example is as follows:

[0039] S1. Disperse titanium dioxide (TiO 2) 5 parts of nanoparticles are dispersed in 45 parts of water, ultrasonicated for 1 hour, and stirred at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0040] S2. Subsequently, 50 parts of epoxy resin E51 are injected into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and the stirring speed is maintained at 600 - 3000 r / min for 1 hour, thereby emulsifying to form a Pickering emulsion type sizing agent of water-in-oil.

[0041] The above sizing agent is diluted with water to a solid content of 2 wt% and placed in an impregnating bath, and the PBO fiber is immersed in the sizing agent. The sizing time is controlled to be 20 s, and after sizing, the fiber is dried at 120 °C. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the intensity retention rate is 91%.

[0042] Example 4

[0043] The preparation method of the sizing agent for PBO fiber with ultraviolet radiation resistance in this example is as follows:

[0044] S1. Zinc oxide (ZnO) nanoparticles with a diameter of 300 nm (5 parts) are dispersed in 40 parts of water, ultrasonicated for 1 hour, and stirred at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0045] S2. Subsequently, 55 parts of epoxy resin E54 are injected into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and the stirring speed is maintained at 600 - 3000 r / min for 1 hour, thereby emulsifying to form a Pickering emulsion type sizing agent of water-in-oil.

[0046] The above sizing agent is diluted with water to a solid content of 2 wt% and placed in an impregnating bath, and the PBO fiber is immersed in the sizing agent. The sizing time is controlled to be 20 s, and after sizing, the fiber is dried at 120 °C. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the tensile strength retention rate of the sized PBO fiber is 90%.

[0047] Example 5

[0048] The preparation method of the sizing agent for PBO fiber with ultraviolet radiation resistance in this example is as follows:

[0049] S1. Titanium dioxide (TiO 2) 3 parts of nanoparticles and 3 parts of zinc oxide (ZnO) nanoparticles are dispersed in 44 parts of water, ultrasonicated for 1 hour, and stirred at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0050] S2. Subsequently, 50 parts of epoxy resin E54 is injected into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and the stirring speed is maintained at 600 - 3000 r / min for 1 hour, thereby emulsifying to form a Pickering emulsion type sizing agent of water-in-oil.

[0051] The above sizing agent is diluted with water to a solid content of 2 wt% and placed in an impregnating bath, and the PBO fiber is immersed in the sizing agent. The sizing time is controlled to be 20 s, and after sizing, the fiber is dried at 120 °C. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the tensile strength retention rate of the sized PBO fiber is 93%.

[0052] Example 6

[0053] The preparation method of the sizing agent for ultraviolet radiation-resistant PBO fiber in this example is as follows:

[0054] S1. 5 parts of titanium dioxide (TiO 2 ) nanoparticles with a diameter of 400 nm are dispersed in 35 parts of water, ultrasonicated for 1 hour, and stirred at a speed of 1800 r / min for 1 hour to form an aqueous dispersion;

[0055] S2. Subsequently, 30 parts of epoxy resin E51 and 30 parts of epoxy resin E54 are injected into the aqueous dispersion of nanoparticles at a rate of 2 - 10 mL / min, and the stirring speed is maintained at 600 - 3000 r / min for 1 hour, thereby emulsifying to form a Pickering emulsion type sizing agent of water-in-oil.

[0056] The above sizing agent is diluted with water to a solid content of 2 wt% and placed in an impregnating bath, and the PBO fiber is immersed in the sizing agent. The sizing time is controlled to be 20 s, and after sizing, the fiber is dried at 120 °C. After irradiation with a xenon lamp (wavelength 365 nm, intensity 16 mV / cm 2 ) for 168 h, the tensile strength retention rate of the sized PBO fiber is 91%.

Claims

1. A UV-resistant PBO fiber sizing agent, characterized in that: In terms of weight, the sizing agent comprises 2 to 10 parts of UV-resistant nanoparticles, 20 to 50 parts of epoxy resin main slurry, and the rest is water.

2. The ultraviolet radiation resistant PBO fiber sizing agent according to claim 1, characterized in that: The sizing agent is an oil-in-water Pickering emulsion, and the ultraviolet-resistant nanoparticles are coated on the surface of the epoxy resin.

3. The ultraviolet radiation resistant PBO fiber sizing agent according to claim 1, characterized in that: The ultraviolet-resistant nanoparticles include at least one of titanium dioxide and zinc oxide, and have a diameter ranging from 200 to 500 nm.

4. The ultraviolet radiation resistant PBO fiber sizing agent according to claim 1, characterized in that: The epoxy resin main slurry includes at least one of epoxy resin E44, epoxy resin E51, and epoxy resin E54.

5. The ultraviolet radiation resistant PBO fiber sizing agent according to claim 1, characterized in that: The water includes deionized water.

6. A method for preparing a UV-resistant PBO fiber sizing agent, comprising the following steps: S1. dispersing the UV-resistant nanoparticles in water, ultrasonically treating, and then stirring to form an aqueous dispersion; S2. Inject the epoxy resin main slurry into the aqueous dispersion described in step S1 and stir to emulsify and form an oil-in-water Pickering emulsion.

7. The method for preparing the ultraviolet radiation resistant PBO fiber sizing agent according to claim 6, characterized in that: In step S1, the ultrasonic time is 0.5 to 1.5 hours, and the stirring speed is 1500 to 2000 r / min.

8. The method for preparing the ultraviolet radiation resistant PBO fiber sizing agent according to claim 6, characterized in that: In step S2, the injection speed of the epoxy resin main slurry is 2-10 mL / min, the stirring speed is 600-3000 r / min, and the stirring time is 0.5-1.5 h.

9. Use of the ultraviolet radiation resistant PBO fiber sizing agent according to any one of claims 1 to 5 in a sizing process, characterized in that: After the sizing agent is diluted with water to a solid content of 2wt% to 5wt%, the PBO fiber is sized by an immersion method.

10. Use of the ultraviolet radiation resistant PBO fiber sizing agent according to claim 9 in a sizing process, characterized in that: When sizing the PBO fiber, the sizing time is controlled to be 10 to 30 seconds, and the PBO fiber is dried at 100 to 150° C. after sizing.

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