Environment-friendly composite fluoride-free flame-retardant polycarbonate material as well as preparation method and application thereof

Abstract

The invention discloses an environment-friendly composite fluoride-free flame-retardant polycarbonate material as well as a preparation method and application thereof, and relates to the technical field of polycarbonate. The environment-friendly composite fluoride-free flame-retardant polycarbonate material is prepared from the following raw material components in parts by weight: 80 parts of PC, 10 to 15 parts of a lignin-based flame retardant, 5 to 10 parts of modified carbon fibers, 5 to 10 parts of PI, 3 to 5 parts of SEBS-g-GMA and 0.3 to 0.5 part of an antioxidant. Through the synergistic effect of the lignin-based flame retardant, the modified carbon fiber, PI and SEBS-g-GMA, the environment-friendly composite fluoride-free flame-retardant polycarbonate material with excellent flame retardance and wear resistance is comprehensively prepared, and can be widely applied to related plastic parts of automobiles and electronic products as flame-retardant resin.

Description

Technical Field

[0001] This invention relates to the field of polycarbonate technology, specifically to an environmentally friendly composite fluorine-free flame-retardant polycarbonate material, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC), as a high-performance engineering plastic, has been widely used in many fields such as electronic and electrical enclosures, automotive parts, building materials, and medical devices due to its excellent light transmittance, impact strength, weather resistance, and thermal stability. However, PC itself has two major defects that seriously restrict its application in demanding scenarios: insufficient flame retardancy and poor abrasion resistance.

[0003] Traditional PC flame retardant modification largely relies on fluorinated flame retardants (or halogenated flame retardants such as decabromodiphenyl ether). While these flame retardants effectively improve flame retardant performance, they pose serious environmental and health risks. Fluorinated flame retardants are difficult to degrade and easily accumulate in ecosystems, causing long-term harm to water bodies, soil, and biodiversity. Halogenated flame retardants release toxic and harmful gases (such as hydrogen bromide) during combustion, polluting the environment and potentially damaging the human respiratory and nervous systems. With increasing environmental awareness, the application of these PC materials has been significantly limited. Therefore, developing fluorine-free and halogen-free environmentally friendly flame retardants has become a core development direction in the field of PC modification.

[0004] In terms of abrasion resistance modification, traditional solutions often involve adding fillers such as glass fiber, graphite, and molybdenum disulfide. However, glass fiber can easily reduce the light transmittance of PC, and uneven dispersion can lead to fluctuations in the material's mechanical properties. Furthermore, these fillers are prone to "migration and precipitation" over time, resulting in a decrease in abrasion resistance. Meanwhile, existing modification solutions often struggle to balance flame retardancy and abrasion resistance—adding a flame retardant alone may reduce the material's toughness and abrasion resistance, while adding abrasion-resistant fillers may affect the dispersion and flame retardant efficiency of the flame retardant. Achieving a synergistic optimization of "environmentally friendly flame retardancy + high abrasion resistance" has become a pressing technical challenge for the industry.

[0005] Based on this, the present invention provides an environmentally friendly composite fluorine-free flame-retardant polycarbonate material and its preparation method, which is of great significance. Summary of the Invention

[0006] The purpose of this invention is to provide an environmentally friendly composite fluorine-free flame-retardant polycarbonate material, its preparation method, and its application, so as to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: An environmentally friendly composite fluorine-free flame-retardant polycarbonate material is prepared by comprising the following raw material components in parts by weight: 80 parts PC, 10-15 parts lignin-based flame retardant, 5-10 parts modified carbon fiber, 5-10 parts PI, 3-5 parts SEBS-g-GMA, and 0.3-0.5 parts antioxidant.

[0008] Furthermore, the preparation method of the environmentally friendly composite fluorine-free flame-retardant polycarbonate material includes the following steps: S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, lignin and maleic anhydride are added to acetic acid and stirred at 30-40℃ for 2-6 hours. After filtration, washing and drying, maleic anhydride-modified lignin is obtained. S12: Maleic anhydride modified lignin, ABS, and dicumyl peroxide are stirred and mixed for 10-20 minutes, added to a screw extruder, melt-blended, extruded and granulated to obtain ABS grafted modified lignin. S13: Under nitrogen protection, DOPO and ABS grafted modified lignin are added to N,N-dimethylformamide, stirred and mixed for 10-20 min, and reacted at 115-130℃ for 6-12 h. After filtration, washing and drying, lignin-based flame retardant is obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 65-70 wt% nitric acid solution, soak them at 70-90℃ for 1-3 hours, filter, wash, and dry to obtain oxidized carbon fibers; S22: (1) Add mercaptosilane coupling agent to 70-80wt% ethanol aqueous solution, adjust pH to 5-5.5, stir and mix for 20-40min to obtain mercaptosilane hydrolysate; (2) Add oxidized carbon fiber to mercaptosilane hydrolysate for soaking treatment for 1-3h, filter, wash, and vacuum dry to obtain mercapto modified carbon fiber; S23: Under nitrogen protection, mercapto-modified carbon fiber, 1,1-bis(diethoxyphosphoryl)ethylene, glycidyl methacrylate, and photoinitiator were added to anhydrous ethanol and stirred for 10-20 min. Under 365 nm ultraviolet light irradiation, the mixture was stirred and reacted for 1-2 h. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: PC, lignin-based flame retardant, modified carbon fiber, PI, SEBS-g-GMA, and antioxidant are stirred and mixed for 10-20 minutes, added to a screw extruder, melt-blended, extruded and granulated to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0009] Furthermore, the preparation of maleic anhydride-modified lignin includes the following raw material components in parts by weight: 5 parts lignin, 1-2 parts maleic anhydride, and 30 parts acetic acid.

[0010] Furthermore, the preparation of the ABS grafted modified lignin includes the following raw material components in parts by weight: 5 parts maleic anhydride modified lignin, 3-5 parts ABS, and 0.01-0.02 parts dicumyl peroxide.

[0011] Furthermore, in S12, the process parameters of the screw extruder are: melt blending temperature of 190~210℃, melt blending time of 10~20min, and screw speed of 200~300r / min.

[0012] Furthermore, the preparation of the lignin-based flame retardant includes the following raw material components in parts by weight: 0.5-1 parts of DOPO, 5 parts of ABS grafted modified lignin, and 20 parts of N,N-dimethylformamide.

[0013] Furthermore, the ratio of the carbon fiber to the nitric acid solution is 1g:10mL.

[0014] Furthermore, the volume ratio of the mercaptosilane coupling agent and the aqueous ethanol solution is (0.05~0.1):1.

[0015] Furthermore, the mercaptosilane coupling agent is one or a combination of two of γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane.

[0016] Furthermore, the ratio of the oxidized carbon fiber to the mercaptosilane hydrolysate is 1g:5mL.

[0017] Furthermore, the modified carbon fiber preparation comprises the following raw material components in parts by weight: 5 parts of mercapto-modified carbon fiber, 0.5-1.5 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 1-2 parts of glycidyl methacrylate, 0.1-0.2 parts of photoinitiator, and 25 parts of anhydrous ethanol.

[0018] Furthermore, in S31, the process parameters of the screw extruder are: melt blending temperature of 230~250℃, melt blending time of 10~20min, and screw speed of 200~300r / min.

[0019] Furthermore, the application of an environmentally friendly composite fluorine-free flame-retardant polycarbonate material in flame-retardant plastics.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are: (1) In this invention, maleic anhydride is first used to modify lignin through esterification to obtain maleic anhydride-modified lignin; then, it is melt-grafted with ABS to obtain ABS-grafted modified lignin; finally, DOPO is grafted onto the ABS-grafted modified lignin to prepare a lignin-based flame retardant. Because the lignin flame retardant contains ABS segments, it has excellent compatibility with PC resin. Furthermore, because it also contains lignin structure and grafted DOPO structure, the flame retardant properties of PC resin can be significantly improved through the combined effect of these two factors.

[0021] (2) In this invention, carbon fibers are sequentially oxidized and then thiolized to obtain thiol-modified carbon fibers; subsequently, phosphoryl groups and epoxy groups are grafted onto the carbon fibers via click reaction to obtain modified carbon fibers. Due to the presence of epoxy groups, the modified carbon fibers can react with oxygen-containing active groups on PC resin, thus exhibiting good compatibility with PC resin; in addition, the modified carbon fibers also contain phosphoryl groups, which can synergistically enhance the flame retardant properties of PC resin with lignin-based flame retardants.

[0022] (3) Lignin-based flame retardants and modified carbon fibers can also be used as fillers, which not only improve the flame retardant properties of PC resin, but also significantly improve the poor wear resistance of PC resin.

[0023] (4) In order to further improve the poor wear resistance of PC resin and give PC resin better flame retardant properties, PI resin is added in this invention. It has excellent wear resistance and flame retardant properties, which can further synergize the flame retardant and wear resistance properties of lignin-based flame retardant and modified carbon fiber reinforced PC resin.

[0024] (5) Considering that the compatibility of PI resin in PC resin is not good, SEBS-g-GMA is further added as a compatibility agent in this invention to improve the compatibility of PI resin and PC resin, thereby better achieving the enhancement of the flame retardant and wear resistance properties of PC resin.

[0025] In summary, this invention utilizes the synergistic effect of lignin-based flame retardants, modified carbon fibers, PI, and SEBS-g-GMA to comprehensively prepare an environmentally friendly composite fluorine-free flame-retardant polycarbonate material with excellent flame retardant and wear resistance. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that the following quantities are by weight, and there are no special restrictions on the suppliers of all raw materials involved in this invention. Exemplary examples include: In the following examples, alkali lignin (catalog number 370959) and carbon fiber (diameter × length 100nm × 20μm) were purchased from Merck Reagents Ltd. 1,1-Bis(diethoxyphosphoryl)ethylene, CAS No. 37465-31-9; DOPO, purity ≥99%; both purchased from Zhengzhou Alpha Chemical Co., Ltd. Maleic anhydride, purity ≥99%; γ-mercaptopropyltriethoxysilane, purity ≥99%; glycidyl methacrylate, purity ≥99%; photoinitiator, model MBP; antioxidant, model 1076; all purchased from Shanghai Dingmiao Chemical Technology Co., Ltd. PC, model URZ2500, melt flow rate 54g / 10min; ABS, model GP-AF312B, melt flow rate 55g / 10min; both purchased from Shunbang New Materials Co., Ltd. PI, model JHPI-20, purchased from Junhua Special Engineering Plastics; SEBS-g-GMA, product number YY2351, was purchased from Wuxi Yiyuan New Material Technology Co., Ltd.; all other raw materials were purchased commercially; each part by weight is 100g.

[0028] Example 1: A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S22: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of oxidized carbon fiber to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon fiber; wherein the ratio of oxidized carbon fiber to mercaptosilane hydrolysate is 1 g: 5 mL; S23: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: Mix 80 parts PC, 12.5 parts lignin-based flame retardant, 7.5 parts modified carbon fiber, 7.5 parts PI, 4 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0029] Example 2: A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: Example 2 is based on Example 1, but with adjustments made to the following: the amount of raw material components used in the environmentally friendly composite fluorine-free flame-retardant polycarbonate material; S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S22: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of oxidized carbon fiber to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon fiber; wherein the ratio of oxidized carbon fiber to mercaptosilane hydrolysate is 1 g: 5 mL; S23: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: Mix 80 parts PC, 10 parts lignin-based flame retardant, 5 parts modified carbon fiber, 5 parts PI, 3 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0030] Example 3: A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: Example 3 is based on Example 1, but with adjustments made to the following: the amount of raw material components in the environmentally friendly composite fluorine-free flame-retardant polycarbonate material; S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S22: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of oxidized carbon fiber to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon fiber; wherein the ratio of oxidized carbon fiber to mercaptosilane hydrolysate is 1 g: 5 mL; S23: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: Mix 80 parts PC, 15 parts lignin-based flame retardant, 10 parts modified carbon fiber, 10 parts PI, 5 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0031] The following comparative experiments are based on Example 1, with comparative examples 1 to 4, as detailed below: Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustment: no lignin-based flame retardant is added, while other processes remain unchanged; A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: S1: Preparation of modified carbon fiber: S11: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S12: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of carbon dioxide to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon dioxide; wherein the ratio of carbon dioxide to mercaptosilane hydrolysate is 1 g: 5 mL; S13: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S2: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S21: Mix 80 parts PC, 7.5 parts modified carbon fiber, 7.5 parts PI, 4 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0032] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following adjustment: no modified carbon fiber is added, and other processes remain unchanged; A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S21: Mix 80 parts PC, 12.5 parts lignin-based flame retardant, 7.5 parts PI, 4 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0033] Comparative Example 3: Comparative Example 3 is based on Example 1, with the following adjustment: PI is not added, while other processes remain unchanged; A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S22: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of oxidized carbon fiber to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon fiber; wherein the ratio of oxidized carbon fiber to mercaptosilane hydrolysate is 1 g: 5 mL; S23: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: Mix 80 parts PC, 12.5 parts lignin-based flame retardant, 7.5 parts modified carbon fiber, 4 parts SEBS-g-GMA, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0034] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustment: SEBS-g-GMA is not added, while other processes remain unchanged; A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material: S1: Preparation of lignin-based flame retardants: S11: Under nitrogen protection, 15 parts of alkali lignin and 4.5 parts of maleic anhydride were added to 90 parts of acetic acid and stirred at 35°C for 4 hours. After filtration, washing and drying, maleic anhydride modified lignin was obtained. S12: Mix 15 parts of maleic anhydride modified lignin, 12 parts of ABS, and 0.045 parts of dicumyl peroxide for 15 minutes, add to a screw extruder, melt blend at 200℃ for 15 minutes, and extrude and granulate to obtain ABS grafted modified lignin. S13: Under nitrogen protection, 2.25 parts of DOPO and 15 parts of ABS grafted modified lignin were added to 60 parts of N,N-dimethylformamide, stirred and mixed for 15 min, and reacted at 125℃ for 9 h. After filtration, washing and drying, lignin-based flame retardant was obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in a 70wt% nitric acid solution, soak them at 80℃ for 2 hours, filter, wash, and dry to obtain oxidized carbon fibers; wherein the ratio of carbon fibers to nitric acid solution is 1g:10mL. S22: (1) Add γ-mercaptopropyltriethoxysilane to a 75wt% aqueous ethanol solution, adjust the pH to 5, stir and mix for 30 min to obtain a mercaptosilane hydrolysate, wherein the volume ratio of γ-mercaptopropyltriethoxysilane to the aqueous ethanol solution is 0.075:1; (2) Add 10 parts of oxidized carbon fiber to the mercaptosilane hydrolysate for soaking and treatment for 2 h, filter, wash, and vacuum dry to obtain mercapto-modified carbon fiber; wherein the ratio of oxidized carbon fiber to mercaptosilane hydrolysate is 1 g: 5 mL; S23: Under nitrogen protection, 10 parts of mercapto-modified carbon fiber, 2 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 3 parts of glycidyl methacrylate, and 0.3 parts of photoinitiator were added to 50 parts of anhydrous ethanol and stirred for 15 min. The mixture was then stirred and reacted for 1.5 h under 365 nm ultraviolet light irradiation. After filtration, washing, and vacuum drying, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: Mix 80 parts PC, 12.5 parts lignin-based flame retardant, 7.5 parts modified carbon fiber, 7.5 parts PI, and 0.4 parts antioxidant for 15 minutes, add to a screw extruder, melt blend at 240℃ for 15 minutes, and extrude and granulate to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

[0035] Performance Testing: The environmentally friendly composite fluorine-free flame-retardant polycarbonate materials prepared in Examples 1-3 and Comparative Examples 1-4 were added to a screw extruder and melted at 240℃ to extrude test specimens measuring 150mm (length) × 10mm (width) × 3mm (thickness). The limiting oxygen index was tested according to GB / T 2406.2. The wear was measured using a Tiber abrasion tester at 72 r / min, a load of 250g, and a CS-10 abrasion-resistant rubber wheel for 1 hour, according to ASTM D4060. The test results are shown in Table 1 below. Table 1

[0036] Conclusion: As can be seen from the data comparison of the examples and comparative examples in Table 1 above, the present invention comprehensively prepares an environmentally friendly composite fluorine-free flame-retardant polycarbonate material with excellent flame retardant and wear resistance through the synergistic effect of lignin-based flame retardant, modified carbon fiber, PI, and SEBS-g-GMA. All four components are indispensable.

[0037] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material, characterized in that: Includes the following steps: S1: Preparation of lignin-based flame retardants: S11: Add lignin and maleic anhydride to acetic acid, stir and react at 30~40℃ for 2~6h, and then separate and purify to obtain maleic anhydride modified lignin; S12: Maleic anhydride modified lignin, ABS, and dicumyl peroxide are stirred and mixed evenly, added to a screw extruder, melt-blended, extruded and granulated to obtain ABS grafted modified lignin. S13: DOPO and ABS grafted lignin are added to N,N-dimethylformamide, stirred and mixed evenly, and reacted at 115~130℃ for 6~12h. After separation and purification, lignin-based flame retardant is obtained. S2: Preparation of modified carbon fibers: S21: Disperse carbon fibers in nitric acid solution, soak them, and then separate and purify them to obtain oxidized carbon fibers; S22: (1) Add mercaptosilane coupling agent to an ethanol aqueous solution, adjust the pH to 5~5.5, stir and mix to obtain mercaptosilane hydrolysate; (2) Add oxidized carbon fiber to the mercaptosilane hydrolysate for soaking treatment, and after separation and purification, obtain mercapto modified carbon fiber; S23: Thiol-modified carbon fiber, 1,1-bis(diethoxyphosphoryl)ethylene, glycidyl methacrylate, and photoinitiator were added to anhydrous ethanol, stirred and mixed evenly, and reacted under ultraviolet light. After separation and purification, modified carbon fiber was obtained. S3: Preparation of environmentally friendly composite fluorine-free flame-retardant polycarbonate materials: S31: PC, lignin-based flame retardant, modified carbon fiber, PI, SEBS-g-GMA, and antioxidant are stirred and mixed evenly, added to a screw extruder, melt-blended, extruded and granulated to obtain an environmentally friendly composite fluorine-free flame-retardant polycarbonate material.

2. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: The preparation of the environmentally friendly composite fluorine-free flame-retardant polycarbonate material includes the following raw material components in parts by weight: 80 parts PC, 10-15 parts lignin-based flame retardant, 5-10 parts modified carbon fiber, 5-10 parts PI, 3-5 parts SEBS-g-GMA, and 0.3-0.5 parts antioxidant.

3. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: In S11, the preparation of maleic anhydride modified lignin includes the following raw material components in parts by weight: 5 parts lignin, 1-2 parts maleic anhydride, and 30 parts acetic acid; In S12, the preparation of ABS grafted modified lignin includes the following raw material components in parts by weight: 5 parts maleic anhydride modified lignin, 3-5 parts ABS, and 0.01-0.02 parts dicumyl peroxide; In S13, the preparation of the lignin-based flame retardant includes the following raw material components in parts by weight: 0.5-1 parts of DOPO, 5 parts of ABS grafted modified lignin, and 20 parts of N,N-dimethylformamide.

4. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: In S21, the ratio of the carbon fiber to the nitric acid solution is 1g:10mL; In S22, the volume ratio of the mercaptosilane coupling agent and the ethanol aqueous solution is (0.05~0.1):1; the ratio of the oxidized carbon fiber and the mercaptosilane hydrolysate is 1g:5mL. In S23, the modified carbon fiber preparation includes the following raw material components in parts by weight: 5 parts of mercapto-modified carbon fiber, 0.5-1.5 parts of 1,1-bis(diethoxyphosphoryl)ethylene, 1-2 parts of glycidyl methacrylate, 0.1-0.2 parts of photoinitiator, and 25 parts of anhydrous ethanol.

5. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: The mercaptosilane coupling agent is one or a combination of two of γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane.

6. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: In S12, the process parameters of the screw extruder are: melt blending temperature of 190~210℃, melt blending time of 10~20min, and screw speed of 200~300r / min.

7. The method for preparing an environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 1, characterized in that: In S31, the process parameters of the screw extruder are: melt blending temperature of 230~250℃, melt blending time of 10~20min, and screw speed of 200~300r / min.

8. An environmentally friendly composite fluorine-free flame-retardant polycarbonate material, characterized in that: It is prepared by any one of the preparation methods of the environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to any one of claims 1 to 7.

9. The application of the environmentally friendly composite fluorine-free flame-retardant polycarbonate material according to claim 8 as a flame-retardant plastic in automobiles and electronic products.

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