High-strength glass fiber modified plastic and method for producing the same

Abstract

The application relates to a high-strength glass fiber modified plastic and a preparation method thereof, and belongs to the technical field of high polymer composite materials. The glass fiber modified plastic comprises the following components in parts by weight: resin 40-90 parts, modified glass fiber 10-20 parts, lubricant 0.4-3 parts and antioxidant 0.5-2 parts; the modified glass fiber comprises a glass fiber matrix, a polydopamine layer coated on the surface of the glass fiber matrix and Sr-doped ZnS nanosheet layers formed on the surface of the polydopamine layer; by constructing a polydopamine / Sr-doped ZnS nanosheet composite interface layer on the surface of the glass fiber, the interface bonding force between the glass fiber and the plastic matrix is significantly improved, meanwhile, the composite material is endowed with excellent ultraviolet aging resistance, the obtained glass fiber modified plastic has high strength and high durability, and can be widely applied in the fields of automobile industry, aerospace, electronic appliances and the like.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to a high-strength glass fiber modified plastic and its preparation method. Background Technology

[0002] Glass fiber reinforced plastics combine the high strength and high modulus of glass fibers with the lightweight and easy-to-process properties of plastic matrices, making them widely used in the automotive, aerospace, electronics, and building materials industries. However, as an inorganic material, glass fiber has poor interfacial compatibility with organic plastic matrices, resulting in weak interfacial bonding. When subjected to external forces, debonding and fiber pull-out easily occur at the interface, limiting further improvements in the composite material's mechanical properties. Furthermore, common plastics such as polyethylene and polypropylene are sensitive to ultraviolet light and are prone to photo-oxidative degradation during long-term outdoor use, leading to a sharp decline in material properties.

[0003] To address the aforementioned issues, CN121022001A discloses a plastic pipe comprising the following materials in parts by weight: 100 parts PVC, 15-18 parts silica composite filler, 2-4 parts maleic anhydride-grafted POE, 4-6 parts epoxidized soybean oil, 3-5 parts calcium-zinc composite heat stabilizer, 2-3 parts silane-impregnated glass fiber, 0.5-1 part calcium stearate, 0.8-1.2 parts polyethylene wax, 1-1.2 parts processing aid, and 0.5-1 part antioxidant. The glass fiber is impregnated with an ethanol solution of silane coupling agent KH-550. One end of the silane coupling agent molecule has a siloxane group that can react with the silanol groups on the surface of the glass fiber, and the other end has an organic functional group that is compatible with the PVC matrix. During impregnation, the siloxane groups undergo hydrolytic condensation with the silanol groups on the glass fiber surface, forming chemical bonds that fix the silane coupling agent to the glass fiber surface. After drying, the organic functional groups exhibit good compatibility and adhesion with the PVC matrix. When the material is subjected to impact, the silane-treated glass fiber effectively prevents crack propagation, disperses impact energy over a wider area, and improves the material's impact strength. However, the interface layer structure formed by the coupling agent is simple, and its effect on improving interfacial bonding is limited, thus failing to improve the overall mechanical properties of the plastic.

[0004] CN120863177A discloses a TPE-PP composite material for folding joints of pet strollers. The base layer, by weight, consists of 50-70% highly crystalline polypropylene, 20-35% glass fiber reinforced polar plastic, 5-10% polyolefin elastomer toughening agent, and 3-5% compatibilizer. The functional layer consists of 40-60% hydrogenated styrene-butadiene-styrene block copolymer, 20-30% polyolefin plasticizer, 15-25% nano-silica, and 2-5% antioxidant. The surface layer consists of 85-90% matrix elastomer, 5-8% polytetrafluoroethylene micropowder, 3-5% silver-zinc zeolite antibacterial agent, and 2-3% UV stabilizer. CN113004667A discloses a plastic product and its manufacturing process, comprising the following components by weight: 100 parts of plastic resin composite material, 1.5-1.7 parts of antioxidant, 1.3-1.5 parts of ultraviolet absorber, 0.7-0.9 parts of quencher, 5-7 parts of glass fiber, and 4-7 parts of activated glass microspheres. The preparation method includes the following steps: S1, mixing the plastic resin composite material, antioxidant, ultraviolet absorber, quencher, glass fiber, activated glass microspheres, and hexadecyltrimethylsilver ammonium bromide according to a set ratio to obtain a mixture; S2, collecting the mixture from step S1 and placing it in a twin-screw extruder, collecting the extruded material, processing it into shape, and allowing it to cool to room temperature. Although the above literature includes an anti-ultraviolet agent, its performance is not optimized, resulting in insufficient ultraviolet resistance in the final plastic product.

[0005] Therefore, developing a glass fiber reinforced plastic that possesses both excellent mechanical strength and UV aging resistance has significant application value. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-strength glass fiber modified plastic and its preparation method. This invention involves sequentially constructing a polydopamine layer (PDA layer) and a Sr-doped ZnS (Sr-ZnS) nanosheet layer in situ on the surface of glass fibers, forming modified glass fibers with an organic-inorganic composite interface layer. This modified glass fiber is then composited with a plastic matrix, resulting in a glass fiber modified plastic with significantly improved mechanical properties and anti-aging properties.

[0007] In a first aspect, the present invention provides a high-strength glass fiber modified plastic, comprising the following components in parts by weight: 40-90 parts resin; 10-20 parts modified glass fiber; 0.4-3 parts lubricant; 0.5-2 parts antioxidant.

[0008] In this invention, the resin is a thermoplastic resin, which is selected from one or more of polypropylene, polyethylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyetheretherketone.

[0009] In this invention, the lubricant may be selected from one or more of calcium stearate, zinc stearate, polyethylene wax, and ethylene bis-stearamide.

[0010] In this invention, the antioxidant may be selected from one or more of hindered phenolic antioxidants and phosphite antioxidants.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned glass fiber modified plastic, comprising the following steps: Step (1): In-situ coating of polydopamine layer Glass fibers were impregnated in Tris buffer solution of dopamine hydrochloride, and an in-situ polymerization reaction was carried out on the surface of the glass fibers to obtain a modified glass fiber precursor with a polydopamine layer on the surface. Step (2): In-situ growth of Sr-doped ZnS nanosheets The modified glass fiber precursor obtained in step (1) was dispersed in a mixed solvent of deionized water and glycerol, and zinc source, sulfur source, strontium source and urea were added to carry out a hydrothermal reaction to generate Sr-doped ZnS nanosheets in situ on the surface of the polydopamine layer, thus obtaining modified glass fiber.

[0012] Preferably, the mixed solvent is a mixed solution of deionized water and glycerol, wherein the volume ratio of deionized water to glycerol is 1:3-1:4.

[0013] Preferably, the zinc source is one or more of zinc nitrate, zinc chloride, or zinc acetate; The sulfur source is one or more of thiourea, thioacetamide, or sodium sulfide; The strontium source is one or more of strontium nitrate, strontium chloride, or strontium acetate; The molar ratio of the zinc source to the sulfur source is 1:1, and the molar ratio of the zinc source to the strontium source is 1:0.05-1:0.1; the molar ratio of the added urea to the zinc source is 2:1-3:1, and the concentration of dopamine hydrochloride is 1-3 g / L.

[0014] Preferably, the conditions for the hydrothermal reaction include: a reaction temperature of 150-220°C and a reaction time of 12-24 hours.

[0015] Step (3): Melt blending The resin, lubricant, antioxidant and modified glass fiber obtained in step (2) are mixed in proportion and then melt-blended and extruded into granules by a twin-screw extruder. The extrusion temperature is 180-280℃ according to the melting point of the resin and the screw speed is 100-300 rpm.

[0016] Thirdly, the present invention also provides the application of the above-mentioned modified glass fiber in plastic reinforcement.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This application first coats a thin layer of PDA onto the surface of glass fiber. Glycerol molecules can interact with the PDA layer through hydrogen bonds, increasing the interlayer spacing and free volume of the PDA layer, thus enabling Zn... 2+ 、Sr 2+ Ions can diffuse into the interior of the PDA layer rather than simply adsorbing on the surface. This 'embedded' nucleation method, combined with the slow-release effect of urea, induces ZnS crystal nuclei to grow simultaneously inside and on the surface of the PDA network, forming an interpenetrating network of nanosheets. Through the combined action of the polydopamine layer, deionized water / glycerol mixed solvent, and urea, the uniform and directional growth of Sr-ZnS nanosheets on the glass fiber surface was successfully achieved, forming a composite coating layer with excellent interface reinforcement and UV aging resistance.

[0018] Nanosheet-like ZnS possesses a large specific surface area and abundant edge sites, thus exhibiting excellent ultraviolet absorption capabilities. Through Sr... 2+ Doping can further modulate the band structure and lattice parameters of ZnS, enhancing its absorption efficiency for ultraviolet light. In addition, the nanosheet structure helps to enhance the interfacial bonding force with plastics.

[0019] This invention employs a two-step in-situ growth method, requiring no complex equipment, with mild reaction conditions, and is easily scalable for industrial production. Furthermore, the composite interface layer of this invention exhibits excellent reinforcing effects on various types of plastic matrices, demonstrating good versatility and application prospects. Attached Figure Description

[0020] Figure 1 The image shown is a scanning electron microscope image of the modified glass fiber prepared in Example 1 of the present invention, which shows the Sr-ZnS nanosheet structure uniformly coated on the surface of the glass fiber.

[0021] Figure 2 This is a flowchart illustrating the preparation process of the plastic used in this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Example 1

[0023] Preparation of modified glass fiber (1) In-situ coating of polydopamine layer: 3g of glass fiber was ultrasonically cleaned and dried, then immersed in 0.5L of Tris buffer solution of dopamine hydrochloride (pH=8.5) with a concentration of 2 g / L, and reacted magnetically at room temperature for 12 hours. After the reaction was completed, the glass fiber was removed, washed three times with deionized water, and dried under vacuum at 50℃ to obtain a modified glass fiber precursor with a polydopamine layer on the surface.

[0024] (2) In-situ growth of Sr-doped ZnS nanosheets: The modified glass fiber precursor obtained in step (1) was dispersed in 120 mL of a deionized water / glycerol mixed solvent with a volume ratio of 1:3. Then, 0.01 mol zinc nitrate, 0.01 mol thiourea, and 0.001 mol strontium nitrate were added and stirred until homogeneous. 0.02 mol urea was then added. The mixture was transferred to a hydrothermal reactor and reacted at 180 °C for 24 hours. After natural cooling, the product was removed, washed three times alternately with deionized water and ethanol, and dried under vacuum at 60 °C to obtain modified glass fibers with Sr-ZnS nanosheets grown in situ on the surface.

[0025] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber: 15 parts; lubricant calcium stearate: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation. After granulation, the modified plastic is obtained by injection molding. Example 2

[0026] Preparation of modified glass fiber (1) In-situ coating of polydopamine layer: 3g of glass fiber was ultrasonically cleaned and dried, then immersed in 0.5L of Tris buffer solution of dopamine hydrochloride (pH=8.5) with a concentration of 1.8 g / L, and reacted magnetically at room temperature for 15 hours. After the reaction was completed, the glass fiber was removed, washed three times with deionized water, and dried under vacuum at 50℃ to obtain a modified glass fiber precursor with a polydopamine layer on the surface.

[0027] (2) In-situ growth of Sr-doped ZnS nanosheets: The modified glass fiber precursor obtained in step (1) was dispersed in 120 mL of a deionized water / glycerol mixed solvent with a volume ratio of 1:3. Then, 0.01 mol zinc nitrate, 0.01 mol thiourea, and 0.001 mol strontium nitrate were added and stirred until homogeneous. 0.02 mol urea was then added. The mixture was transferred to a hydrothermal reactor and reacted at 170 °C for 18 hours. After natural cooling, the product was removed, washed three times alternately with deionized water and ethanol, and dried under vacuum at 60 °C to obtain modified glass fibers with Sr-ZnS nanosheets grown in situ on the surface.

[0028] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber: 15 parts; lubricant calcium stearate: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation to obtain modified plastics. Example 3

[0029] Preparation of modified glass fiber (1) In-situ coating of polydopamine layer: 3g of glass fiber was ultrasonically cleaned and dried, then immersed in 0.5L of Tris buffer solution of dopamine hydrochloride (pH=8) with a concentration of 2 g / L, and reacted magnetically at room temperature for 12 hours. After the reaction was completed, the glass fiber was removed, washed three times with deionized water, and dried under vacuum at 50℃ to obtain a modified glass fiber precursor with a polydopamine layer on the surface.

[0030] (2) In-situ growth of Sr-doped ZnS nanosheets: The modified glass fiber precursor obtained in step (1) was dispersed in 120 mL of a deionized water / glycerol mixed solvent with a volume ratio of 1:4. Then, 0.01 mol zinc nitrate, 0.01 mol thiourea, and 0.001 mol strontium nitrate were added and stirred until homogeneous. 0.02 mol urea was then added. The mixture was transferred to a hydrothermal reactor and reacted at 180 °C for 24 hours. After natural cooling, the product was removed, washed three times alternately with deionized water and ethanol, and dried under vacuum at 60 °C to obtain modified glass fibers with Sr-ZnS nanosheets grown in situ on the surface.

[0031] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber: 15 parts; lubricant calcium stearate: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation. After granulation, the modified plastic is obtained by injection molding.

[0032] Comparative Example 1: Preparation of modified glass fiber 3g of glass fiber was ultrasonically cleaned and dried, then dispersed in 120mL of a deionized water / glycerol mixed solvent (deionized water / glycerol volume ratio 1:3). Then, 0.01 mol zinc nitrate, 0.01 mol thiourea, and 0.001 mol strontium nitrate were added, and the mixture was stirred until homogeneous. Finally, 0.02 mol urea was added. The mixture was transferred to a hydrothermal reactor and reacted at 180℃ for 24 hours. After natural cooling, the product was removed, washed three times alternately with deionized water and ethanol, and then vacuum dried at 60℃ to obtain modified glass fiber with Sr-ZnS nanosheets grown in situ on its surface.

[0033] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber: 15 parts; lubricant calcium stearate: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation. After granulation, the modified plastic is obtained by injection molding.

[0034] Comparative Example 2 (1) In-situ coating of polydopamine layer: 3g of glass fiber was ultrasonically cleaned and dried, then immersed in 0.5L of Tris buffer solution of dopamine hydrochloride (pH=8.5) with a concentration of 2 g / L, and reacted magnetically at room temperature for 12 hours. After the reaction was completed, the glass fiber was removed, washed three times with deionized water, and dried under vacuum at 50℃ to obtain a modified glass fiber precursor with a polydopamine layer on the surface.

[0035] (2) In-situ growth of ZnS: The modified glass fiber precursor obtained in step (1) was dispersed in 120 mL of a deionized water / glycerol mixed solvent with a volume ratio of 1:3. Then, 0.01 mol of zinc nitrate and 0.01 mol of thiourea were added, and after stirring evenly, 0.02 mol of urea was added. The mixture was transferred to a hydrothermal reactor and reacted at 180 °C for 24 hours. After natural cooling, the product was taken out, washed three times alternately with deionized water and ethanol, and dried under vacuum at 60 °C to obtain modified glass fibers with ZnS grown in situ on the surface.

[0036] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber: 15 parts; lubricant calcium stearate: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation. After granulation, the modified plastic is obtained by injection molding.

[0037] Comparative Example 3 In-situ coating of polydopamine layer: 3g of glass fiber was ultrasonically cleaned and dried, then immersed in 0.5L of Tris buffer solution (pH=8.5) containing 2g / L dopamine hydrochloride, and reacted magnetically at room temperature for 24 hours. After the reaction was completed, the glass fiber was removed, washed three times with deionized water, and vacuum dried at 50℃ to obtain a modified glass fiber precursor with a polydopamine layer coated on its surface.

[0038] Preparation of polypropylene-based glass fiber modified plastics Weigh each component according to the following parts by weight: polypropylene (PP) resin: 80 parts; modified glass fiber with a polydopamine coating: 15 parts; calcium stearate lubricant: 1 part; antioxidant 1010: 1 part; After the above components are mixed evenly in a high-speed mixer, they are added to a twin-screw extruder for melt blending, extrusion, and granulation to obtain modified plastics.

[0039] The following performance tests were conducted on the 80mm×10mm×4mm standard specimens of plastic injection molded from the above embodiments and comparative examples: Mechanical property testing: Tensile strength is tested according to ASTM D638 standard, and flexural strength is tested according to ASTM D790 standard.

[0040] Aging resistance test: The test specimens were placed in an ultraviolet aging test chamber, with an irradiance of 0.55 W / m²@340nm and a temperature of 60℃. After aging for 200 hours, the tensile strength was tested again, and the tensile strength retention rate was calculated.

[0041] Table 1 project Tensile strength (MPa) Bending strength (MPa) Tensile strength retention rate after aging (%) Example 1 89.1 101.5 90.5 Example 2 85.6 96.8 88.2 Example 3 86.4 98.7 88.4 Comparative Example 1 74.2 85.3 75.5 Comparative Example 2 85.0 97.0 71.8 Comparative Example 3 65.3 73.5 56.5 Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the scope of specific implementation methods based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A glass fiber modified plastic, characterized in that, The components include the following parts by weight: 40-90 parts of resin; Modified glass fiber 10-20 parts; lubricant 0.4-3 parts; antioxidant 0.5-2 parts; The modified glass fiber includes a glass fiber matrix and a polydopamine coating layer covering the surface of the glass fiber matrix; and an Sr-ZnS nanosheet layer grown in situ on the surface of the polydopamine layer.

2. The glass fiber modified plastic according to claim 1, characterized in that, The resin is selected from thermoplastic resins; the thermoplastic resin is selected from one or more of polypropylene, polyethylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyetheretherketone.

3. The glass fiber modified plastic according to claim 1, characterized in that, The lubricant is selected from one or more of calcium stearate, zinc stearate, polyethylene wax, and ethylene bis-stearamide; the antioxidant is selected from one or more of hindered phenolic antioxidants and phosphite antioxidants.

4. A method for preparing glass fiber modified plastic as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Glass fibers are impregnated in Tris buffer solution of dopamine hydrochloride to allow dopamine hydrochloride to undergo in-situ polymerization on the surface of glass fibers, thereby obtaining modified glass fibers with a polydopamine layer on the surface. (2) The modified glass fiber precursor with polydopamine coating on its surface is dispersed in a mixed solvent of deionized water and glycerol, and zinc source, sulfur source, strontium source and urea are added to carry out a hydrothermal reaction to generate Sr-doped ZnS nanosheets in situ on the surface of the polydopamine layer, thereby obtaining modified glass fiber. (3) The resin, lubricant, antioxidant and modified glass fiber obtained in step (2) are melt-blended, extruded and granulated to obtain glass fiber modified plastic.

5. The method for preparing glass fiber modified plastic according to claim 4, characterized in that, The volume ratio of deionized water to glycerol is 1:3 to 1:

4.

6. The method for preparing glass fiber modified plastic according to claim 4, characterized in that, The zinc source is one or more of zinc nitrate, zinc chloride, or zinc acetate; the sulfur source is one or more of thiourea, thioacetamide, or sodium sulfide; and the strontium source is one or more of strontium nitrate, strontium chloride, or strontium acetate.

7. The method for preparing glass fiber modified plastic according to claim 4, characterized in that, The molar ratio of the zinc source to the sulfur source is 1:1, and the molar ratio of the zinc source to the strontium source is 1:0.05-1:0.1; the molar ratio of the amount of urea added to the zinc source is 2:1-3:

1.

8. The method for preparing glass fiber modified plastic according to claim 4, characterized in that, The conditions for the hydrothermal reaction include: a reaction temperature of 150-220℃ and a reaction time of 12-24 hours.

Images