Weather-resistant plastic, its preparation method and application in plastic parts of electric vehicles

Abstract

The application discloses weather-resistant plastic and a preparation method and application thereof in plastic parts of electric vehicles, and relates to the field of polymer materials. In the preparation of the weather-resistant plastic, modified lignin is prepared by reacting alkaline lignin with 2-chloromethyl phenol and formaldehyde, and then with 3-amino pyrrole; modified graphene oxide is prepared by reacting graphene oxide with an ethanol solution of 3-amino pyrrole, and then with anhydrous ferric chloride and a chloroform solution of pyrrole; modified polypropylene is prepared by irradiating polypropylene with gamma rays, then reacting with allyl phosphine dichloride, and then with N-(4-hydroxyphenyl) maleimide and triethylamine; and finally, the modified lignin, the modified graphene oxide and the modified polypropylene are uniformly mixed, extruded, granulated and hot-pressed to obtain the weather-resistant plastic. The weather-resistant plastic prepared by the application has good weather resistance, tensile strength, flame retardance, self-repairing performance and antistatic performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular to a weather-resistant plastic, a preparation method thereof and application of the weather-resistant plastic in plastic parts of electric vehicles. BACKGROUND

[0002] Polypropylene is one of the five most widely used general resins in the world. Due to its regular crystal structure, easy preparation and processing, and good mechanical properties, it has a wide range of applications in the automotive industry, packaging, and building materials. Lignin is the only natural polymer containing aromatic rings in nature, with unique aromatic and aliphatic backbone structures, and abundant functional groups suitable for functionalization. This makes lignin a good substitute for petroleum phenolic polymers, and it can be used in the development of sustainable and functional materials.

[0003] Polypropylene is very susceptible to heat, oxygen, and light in actual production and application, and thus various types of antioxidant additives are added to commercially available polypropylene. Currently, hindered phenols are the main antioxidants used in polypropylene. However, many toxicology reports show that hindered phenols are toxic substances, which undoubtedly adds potential risks to the sales and use of polypropylene. Lignin has a natural polyphenol structure and natural antioxidant effect, and as a biomass material, it is environmentally friendly. The weather-resistant plastic prepared by the present application has good weather resistance, tensile strength, flame retardance, self-repairing performance, and antistatic properties, and has a broad market prospect. SUMMARY

[0004] The present application aims to provide a preparation method of a weather-resistant plastic to solve the problems in the prior art.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] A weather-resistant plastic is prepared by the following steps: 2-chloromethylphenol is reacted with alkaline lignin and formaldehyde to obtain pre-modified lignin; the pre-modified lignin is reacted with 3-aminopyrrole to obtain modified lignin; graphene oxide is reacted with an ethanol solution of 3-aminopyrrole to obtain pyrrole-modified graphene oxide; the pyrrole-modified graphene oxide is reacted with anhydrous ferric chloride and a chloroform solution of pyrrole to obtain modified graphene oxide; polypropylene is treated by gamma ray irradiation and reacted with allyl phosphine dichloride to obtain flame-retardant polypropylene; the flame-retardant polypropylene is reacted with N-(4-hydroxyphenyl) maleimide and triethylamine to obtain modified polypropylene; the modified lignin, modified graphene oxide, and modified polypropylene are uniformly mixed, extruded, granulated, and hot-pressed to obtain the weather-resistant plastic.

[0007] A preparation method of a weather-resistant plastic includes the following preparation steps:

[0008] (1) mixing graphene oxide and deionized water according to a mass ratio of 1:300, preparing graphene oxide suspension by ultrasonic dispersion, adding 3-aminopyrrole ethanol solution with a mass of 40-50 times of graphene oxide, stirring at 200-300 r / min under reflux at 85-95℃ for 20-24 h, filtering, washing the filter cake with anhydrous ethanol for 3-5 times, and drying at 65-75℃ for 4-6 h to prepare pyrrole modified graphene oxide; mixing pyrrole modified graphene oxide suspension, anhydrous ferric chloride and chloroform according to a mass ratio of 1:(1.5-2.5):(10-20), stirring at 200-300 r / min under nitrogen atmosphere at room temperature for 10-20 min, cooling to 0℃, adding pyrrole chloroform solution with a mass of 14-16 times of the pyrrole modified graphene oxide suspension, continuing to stir for 2.5-3.5 h, filtering, washing the filter cake with anhydrous ethanol for 3-5 times, and drying at 65-75℃ for 4-6 h to prepare modified graphene oxide;

[0009] (2) irradiating polypropylene with γ-rays at a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h, mixing the irradiated polypropylene, allyl phosphine dichloride and anhydrous ethanol according to a mass ratio of 1:(0.1-0.2):(40-60), stirring at 200-300 r / min under nitrogen atmosphere at 70-80℃ for 3-4 h, filtering, extracting the filter residue with acetone for 48 h to prepare flame-retardant polypropylene; mixing the flame-retardant polypropylene, N-(4-hydroxyphenyl)maleimide, triethylamine and tetrahydrofuran according to a mass ratio of 1:(0.2-0.3):(0.15-0.25):(30-40), stirring at 200-300 r / min under nitrogen atmosphere at room temperature for 7-9 h, filtering, washing the filter cake with anhydrous ethanol for 3-5 times, and drying at 65-75℃ for 4-6 h to prepare modified polypropylene;

[0010] (3) mixing 2-chloromethylphenol, alkaline lignin and 0.1 mol / L sodium hydroxide solution according to a mass ratio of 1:(1-2):(10-20), stirring at 200-300 r / min at 75-85℃ for 1-2 h, cooling to 55-65℃, adding formaldehyde in an equal molar amount of 2-chloromethylphenol, reacting for 1-2 h, adding formaldehyde in a molar amount of 0.5 times of the modified compound, heating to 75-85℃ and continuing to react for 1-2 h, and removing water by rotary evaporation at 60-70℃ to prepare pre-modified lignin; mixing 3-aminopyrrole, pre-modified lignin, sodium carbonate and tetrahydrofuran according to a mass ratio of 1:(1.2-1.7):(1.1-1.3):(20-30), stirring at 400-600 r / min at room temperature for 3-5 h, filtering, and drying the filter residue at 40-50℃ for 5-7 h to prepare modified lignin;

[0011] (4) mixing the modified lignin, the modified graphene oxide and the modified polypropylene according to a mass ratio of 1:(0.8-1.2):(8-12), extruding and granulating by using a double screw extruder to obtain plastic particles, and treating the plastic particles by using a hot press to obtain the weather-resistant plastic.

[0012] As optimization, the graphene oxide in step (1) is graphene oxide with a diameter of 0.5-3 μm.

[0013] As optimization, the preparation method of the ethanol solution of 3-aminopyrrole in step (1) is mixing 3-aminopyrrole and anhydrous ethanol according to a mass ratio of 1:(40-50) to obtain the ethanol solution; and the preparation method of the chloroform solution of pyrrole is mixing pyrrole and chloroform according to a mass ratio of 1:30 to obtain the chloroform solution.

[0014] As optimization, the polypropylene in step (2) is K8003 type polypropylene.

[0015] As optimization, the alkali lignin in step (3) is industrial-grade alkali lignin.

[0016] As optimization, the structural formula of 2-chloromethyl phenol in step (3) is as follows: .

[0017] As optimization, the process parameters of the double screw extrusion in step (4) are as follows: the temperature of the die head is 165℃, the temperature of the first zone is 170℃, the temperature of the second zone is 175℃, the temperature of the third zone is 180℃, the temperature of the fourth zone is 175℃, and the length of the particles is 2-5 mm.

[0018] As optimization, the process parameters of the hot press treatment in step (4) are as follows: the hot press temperature is 150℃, the hot press time is 6 min, the pressure is 4 MPa, the cold press temperature is room temperature, the cold press time is 6 min, and the cold press pressure is 4 MPa.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] In the preparation of the weather-resistant plastic, the present application reacts 2-chloromethyl phenol with alkali lignin and formaldehyde to obtain pre-modified lignin, reacts the pre-modified lignin with 3-aminopyrrole to obtain modified lignin, reacts graphene oxide with an ethanol solution of 3-aminopyrrole to obtain pyrrole-modified graphene oxide, reacts the pyrrole-modified graphene oxide with anhydrous ferric chloride and a chloroform solution of pyrrole to obtain modified graphene oxide, reacts polypropylene treated by gamma ray irradiation with allyl phosphine dichloride to obtain flame-retardant polypropylene, reacts the flame-retardant polypropylene with N-(4-hydroxyphenyl) maleimide and triethylamine to obtain modified polypropylene, mixes the modified lignin, the modified graphene oxide and the modified polypropylene, and extrudes and granulates and hot-presses to obtain the weather-resistant plastic.

[0021] Firstly, polypyrrole is coated on the surface of graphene oxide, polypyrrole has a large number of conjugated structures, and conductive electrons can jump on the pyrrole ring of the conjugated structure, thereby improving the antistatic performance of the weather-resistant plastic; and the polypyrrole structure on the graphene oxide can form stable chemical crosslinking with the maleimide structure on the modified polypropylene through a thermal reversible reaction, thereby improving the mechanical properties and self-repairing performance of the weather-resistant plastic; the allyl phosphine dichloride is grafted on the polypropylene, so that the weather-resistant plastic contains rich phosphorus elements, and the phosphorus elements have good flame retardant performance, thereby effectively improving the flame retardant performance of the weather-resistant plastic, and the chlorine introduced by the allyl phosphine dichloride can react with N-(4-hydroxyphenyl) maleimide to introduce the maleimide structure on the polypropylene.

[0022] Secondly, lignin contains rich phenolic hydroxyl structures, and the phenolic hydroxyl structures can react with free radicals to capture the electrons of the free radicals, thereby interrupting the chain reaction of the free radicals and effectively improving the weather resistance of the weather-resistant plastic; the modified compound is prepared by reacting 3-aminopyrrole with o-chlorophenol, the pyrrole structure is introduced on the phenol structure, and the lignin is provided with the pyrrole group by the reaction of the phenol and the formaldehyde, and the pyrrole ring conjugated structure on the pyrrole can occur 2+4 cycloaddition reaction with the double bond of the maleimide on the modified polypropylene, the 2+4 cycloaddition reaction is a thermal reversible reaction, which is disconnected at high temperature and combined at low temperature, so that the weather-resistant plastic can realize self-repairing effect under heating condition, and the thermal reversible reaction can form stable chemical crosslinking, thereby improving the self-repairing performance and mechanical properties of the weather-resistant plastic. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] Embodiment 1:

[0025] A preparation method of a weather-resistant plastic, comprising the following preparation steps:

[0026] (1) 3-amino pyrrole, anhydrous ethanol were mixed in a mass ratio of 1:40 to prepare a 3-amino pyrrole ethanol solution; graphene oxide, deionized water were mixed in a mass ratio of 1:300 to prepare a graphene oxide suspension, 40 times the mass of the graphene oxide was added to the 3-amino pyrrole ethanol solution, and the mixture was stirred at 200 r / min at 85°C for 20 h under reflux, then filtered, the filter cake was washed with anhydrous ethanol for 3 times, and dried at 65°C for 4 h to prepare pyrrole modified graphene oxide; the pyrrole modified graphene oxide was mixed with chloroform to prepare a suspension with a concentration of 2.5 mg / ml and ultrasonic treated for 4 h to prepare a pyrrole modified graphene oxide suspension; pyrrole, chloroform were mixed in a mass ratio of 1:30 to prepare a pyrrole chloroform solution; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride, chloroform were mixed in a mass ratio of 1:1.5:10, stirred at 200 r / min at room temperature for 10 min under nitrogen atmosphere, cooled to 0°C, 14 times the mass of the pyrrole modified graphene oxide suspension was added to the pyrrole chloroform solution, and the mixture was continuously stirred for 2.5 h, then filtered, the filter cake was washed with anhydrous ethanol for 3 times, and dried at 65°C for 4 h to prepare modified graphene oxide;

[0027] (2) the polypropylene was irradiated by gamma rays with a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h, the irradiated polypropylene, allyl phosphine dichloride, anhydrous ethanol were mixed in a mass ratio of 1:0.1:40, stirred at 200 r / min at 70°C for 3 h under nitrogen atmosphere, filtered, and the filter residue was extracted with acetone for 48 h to prepare a flame-retardant polypropylene; the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine, tetrahydrofuran were mixed in a mass ratio of 1:0.2:0.15:30, stirred at 200 r / min at room temperature for 7 h under nitrogen atmosphere, filtered, the filter cake was washed with anhydrous ethanol for 3 times, and dried at 65°C for 4 h to prepare a modified polypropylene;

[0028] (3) 2-chloromethyl phenol, alkaline lignin, 0.1 mol / L sodium hydroxide solution were mixed in a mass ratio of 1:1:10, stirred at 200 r / min at 75°C for 1 h, cooled to 55°C, 2-chloromethyl phenol was added in an equal molar amount of formaldehyde, reacted for 1 h, then 0.5 times the molar amount of the modified compound was added to formaldehyde, heated to 75°C and continued to react for 1 h, and water was removed by rotary evaporation at 60°C to prepare a pre-modified lignin; 3-amino pyrrole, pre-modified lignin, sodium carbonate, tetrahydrofuran were mixed in a mass ratio of 1:1.2:1.1:20, stirred at 400 r / min at room temperature for 3 h, filtered, and the filter residue was dried at 40°C for 5 h to prepare a modified lignin;

[0029] (4) The modified lignin, modified graphene oxide and modified polypropylene are mixed in a mass ratio of 1:0.8:8, and then extruded and granulated by a double screw extruder, with the setting of the positions of each section being: head temperature 165℃, first zone temperature 170℃, second zone temperature 175℃, third zone temperature 180℃, and fourth zone temperature 175℃, and the length of the granules being 2mm, to obtain plastic granules; the plastic granules are treated by a hot press, with the hot pressing temperature being 150℃, the hot pressing time being 6min, the pressure being 4MPa, and the cold pressing time at room temperature being 6min, to obtain the weather-resistant plastic.

[0030] Example 2:

[0031] A preparation method of the weather-resistant plastic comprises the following preparation steps:

[0032] (1) 3-Aminopyrrole and anhydrous ethanol are mixed in a mass ratio of 1:45 to obtain an ethanol solution of 3-aminopyrrole; graphene oxide and deionized water are mixed in a mass ratio of 1:300 to obtain a graphene oxide suspension, and 3-aminopyrrole ethanol solution with a mass of 45 times that of the graphene oxide is added, and stirred at 90℃ and 250r / min for 22h, and then filtered, and the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to obtain pyrrole modified graphene oxide; the pyrrole modified graphene oxide is mixed with chloroform to prepare a suspension with a concentration of 2.5mg / ml and ultrasonic treated for 5h to obtain a pyrrole modified graphene oxide suspension; pyrrole and chloroform are mixed in a mass ratio of 1:30 to obtain a chloroform solution of pyrrole; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride and chloroform are mixed in a mass ratio of 1:2:15, stirred at room temperature and 250r / min for 15min under a nitrogen atmosphere, cooled to 0℃, and the chloroform solution of pyrrole with a mass of 15 times that of the pyrrole modified graphene oxide suspension is added, and the stirring is continued for 3h, and then filtered, and the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to obtain modified graphene oxide;

[0033] (2) The polypropylene is irradiated by γ-rays with a radiation dose of 15kGy and a dose rate of 2.5kGy / h, and then the irradiated polypropylene, allyl phosphine dichloride and anhydrous ethanol are mixed in a mass ratio of 1:0.15:50, stirred at 75℃ and 250r / min for 3.5h under a nitrogen atmosphere, filtered, and the filter residue is extracted with acetone for 48h to obtain flame-retardant polypropylene; the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine and tetrahydrofuran are mixed in a mass ratio of 1:0.25:0.2:35, stirred at room temperature and 250r / min for 8h under a nitrogen atmosphere, filtered, and the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to obtain modified polypropylene;

[0034] (3) 2-chloromethyl phenol, alkaline lignin, 0.1 mol / L sodium hydroxide solution were mixed in a mass ratio of 1:1.5:15, stirred at 80°C and 250 r / min for 1.5 h, cooled to 60°C, 2-chloromethyl phenol was added in an equimolar amount of formaldehyde, reacted for 1.5 h, and then 0.5 times the molar amount of formaldehyde was added, the temperature was raised to 80°C and the reaction was continued for 1.5 h, and water was removed by rotary evaporation at 65°C to prepare a pre-modified lignin; 3-aminopyrrole, pre-modified lignin, sodium carbonate, and tetrahydrofuran were mixed in a mass ratio of 1:1.4:1.2:25, stirred at room temperature and 500 r / min for 4 h, filtered, and the filter residue was dried at 45°C for 6 h to prepare a modified lignin;

[0035] (4) The modified lignin, modified graphene oxide, and modified polypropylene were mixed in a mass ratio of 1:1:10, extruded and granulated by a twin-screw extruder, and the temperature of each section was set as follows: 165°C for the head, 170°C for the first section, 175°C for the second section, 180°C for the third section, and 175°C for the fourth section. The length of the granules was 3.5 mm, and plastic granules were prepared. The plastic granules were treated by hot pressing using a hot press at a temperature of 150°C for 6 min under a pressure of 4 MPa, and then cold pressed at room temperature for 6 min under the same pressure to obtain a weather-resistant plastic.

[0036] Example 3:

[0037] A method for preparing a weather-resistant plastic, comprising the following preparation steps:

[0038] (1) 3-aminopyrrole and anhydrous ethanol were mixed in a mass ratio of 1:50 to prepare an ethanol solution of 3-aminopyrrole; graphene oxide and deionized water were mixed in a mass ratio of 1:300, ultrasonically dispersed to prepare a graphene oxide suspension, and 3-aminopyrrole ethanol solution with a mass of 50 times that of the graphene oxide was added and stirred at 300 r / min at 95°C for 24 h under reflux. The filter cake was washed with anhydrous ethanol for 5 times and dried at 75°C for 6 h to prepare pyrrole-modified graphene oxide; the pyrrole-modified graphene oxide was formulated into a suspension with a concentration of 2.5 mg / ml and ultrasonically treated for 6 h to prepare a pyrrole-modified graphene oxide suspension; pyrrole and chloroform were mixed in a mass ratio of 1:30 to prepare a chloroform solution of pyrrole; the pyrrole-modified graphene oxide suspension, anhydrous ferric chloride, and chloroform were mixed in a mass ratio of 1:2.5:20, stirred at room temperature and 300 r / min for 20 min under a nitrogen atmosphere, cooled to 0°C, and 16 times the mass of the pyrrole-modified graphene oxide suspension was added to the chloroform solution of pyrrole, and the stirring reaction was continued for 3.5 h. The filter cake was washed with anhydrous ethanol for 5 times and dried at 75°C for 6 h to prepare modified graphene oxide;

[0039] (2) the polypropylene is irradiated by gamma rays with a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h, the irradiated polypropylene, allyl dichlorophosphine and anhydrous ethanol are uniformly mixed at a mass ratio of 1:0.2:60, stirred at 80℃ and 300 r / min under a nitrogen atmosphere for 4h, the filter residue is extracted with acetone for 48h, and the modified polypropylene is prepared; the modified polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine and tetrahydrofuran are uniformly mixed at a mass ratio of 1:0.3:0.25:40, stirred at room temperature and 300 r / min under a nitrogen atmosphere for 9h, filtered, the filter cake is washed with anhydrous ethanol for 5 times, and dried at 75℃ for 6h;

[0040] (3) 2-chloromethyl phenol, alkali lignin and 0.1 mol / L sodium hydroxide solution are uniformly mixed at a mass ratio of 1:2:20, stirred at 85℃ and 300 r / min for 2h, cooled to 65℃, 2-chloromethyl phenol is added in an equal molar amount of formaldehyde, reacted for 2h, and then 0.5 times the molar amount of formaldehyde of the modified compound is added, heated to 85℃ and reacted for 1-2h, and water is removed by rotary evaporation at 70℃, to prepare a pre-modified lignin; 3-aminopyrrole, pre-modified lignin, sodium carbonate and tetrahydrofuran are uniformly mixed at a mass ratio of 1:1.7:1.3:30, stirred at room temperature and 600 r / min for 5h, filtered, and the filter residue is dried at 50℃ for 7h, to prepare a modified lignin;

[0041] (4) the modified lignin, modified graphene oxide and modified polypropylene are uniformly mixed at a mass ratio of 1:1.2:12, and extruded and granulated by a twin-screw extruder, with the setting of the positions of each section as follows: head temperature 165℃, first zone temperature 170℃, second zone temperature 175℃, third zone temperature 180℃, fourth zone temperature 175℃, and particle length 5mm, to prepare plastic particles; the plastic particles are treated by hot pressing with a hot press at a hot pressing temperature of 150℃, a hot pressing time of 6min, a pressure of 4MPa, and a cold pressing time of 6min at room temperature, to prepare a weather-resistant plastic.

[0042] Comparative Example 1

[0043] A preparation method of a weather-resistant plastic, comprising the following preparation steps:

[0044] (1) 3-amino pyrrole, anhydrous ethanol were mixed according to a mass ratio of 1:45 to prepare a 3-amino pyrrole ethanol solution; graphene oxide, deionized water were mixed according to a mass ratio of 1:300 to prepare a graphene oxide suspension, and the graphene oxide suspension was ultrasonically dispersed; 3-amino pyrrole ethanol solution with a mass of 45 times that of the graphene oxide was added, and the mixture was stirred at 90°C and 250 r / min for 22 h under reflux; the filter cake was washed with anhydrous ethanol for 4 times, and dried at 70°C for 5 h to prepare pyrrole modified graphene oxide; the pyrrole modified graphene oxide was mixed with chloroform to prepare a suspension with a concentration of 2.5 mg / ml and ultrasonically treated for 5 h to prepare a pyrrole modified graphene oxide suspension; pyrrole, chloroform were mixed according to a mass ratio of 1:30 to prepare a pyrrole chloroform solution; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride, chloroform were mixed according to a mass ratio of 1:2:15, stirred at room temperature and 250 r / min for 15 min under a nitrogen atmosphere, cooled to 0°C, and pyrrole chloroform solution with a mass of 15 times that of the pyrrole modified graphene oxide suspension was added, and the mixture was continuously stirred for 3 h; the filter cake was washed with anhydrous ethanol for 4 times, and dried at 70°C for 5 h to prepare modified graphene oxide;

[0045] (2) polypropylene was irradiated with gamma rays at a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h; the irradiated polypropylene, N-allyl maleimide, and anhydrous ethanol were mixed according to a mass ratio of 1:0.15:50, stirred at 75°C and 250 r / min for 3.5 h under a nitrogen atmosphere, filtered, and the filter residue was extracted with acetone for 48 h to prepare modified polypropylene;

[0046] (3) 2-chloromethyl phenol, alkaline lignin, and 0.1 mol / L sodium hydroxide solution were mixed according to a mass ratio of 1:1.5:15, stirred at 80°C and 250 r / min for 1.5 h, cooled to 60°C, and formaldehyde with an equivalent amount of 2-chloromethyl phenol was added, reacted for 1.5 h, and then formaldehyde with an amount of 0.5 times that of the modified compound was added, and the mixture was continuously reacted for 1.5 h at 80°C; water was removed by rotary evaporation at 65°C to prepare a pre-modified lignin; 3-amino pyrrole, pre-modified lignin, sodium carbonate, and tetrahydrofuran were mixed according to a mass ratio of 1:1.4:1.2:25, stirred at room temperature and 500 r / min for 4 h, filtered, and the filter residue was dried at 45°C for 6 h to prepare modified lignin;

[0047] (4) modified lignin, modified graphene oxide, and modified polypropylene were mixed according to a mass ratio of 1:1:10, and extruded and granulated by a twin-screw extruder; the settings of each section were as follows: head temperature 165°C, first zone temperature 170°C, second zone temperature 175°C, third zone temperature 180°C, fourth zone temperature 175°C, and particle length 3.5 mm to prepare plastic particles; the plastic particles were hot-pressed by a hot press at a hot-pressing temperature of 150°C, a hot-pressing time of 6 min, a pressure of 4 MPa, and a cold-pressing time of 6 min at room temperature to prepare weather-resistant plastic.

[0048] Comparative Example 2:

[0049] A preparation method of a weather-resistant plastic, comprising the following preparation steps:

[0050] (1) 3-aminopyrrole, anhydrous ethanol were mixed in a mass ratio of 1:45 to prepare an ethanol solution of 3-aminopyrrole; graphene oxide, deionized water were mixed in a mass ratio of 1:300, and an ultrasonic dispersion was prepared to obtain a graphene oxide suspension, 45 times the mass of the graphene oxide was added to the ethanol solution of 3-aminopyrrole, and stirred at 90°C and 250 r / min for 22 h; the filter cake was washed with anhydrous ethanol for 4 times, and dried at 70°C for 5 h to obtain pyrrole modified graphene oxide; the pyrrole modified graphene oxide was prepared into a suspension with a concentration of 2.5 mg / ml and ultrasonic treated for 5 h to obtain a pyrrole modified graphene oxide suspension; pyrrole, chloroform were mixed in a mass ratio of 1:30 to prepare a chloroform solution of pyrrole; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride, chloroform were mixed in a mass ratio of 1:2:15, stirred at room temperature and 250 r / min for 15 min under nitrogen atmosphere, cooled to 0°C, 15 times the mass of the pyrrole modified graphene oxide suspension was added to the chloroform solution of pyrrole, and continued to be stirred for 3 h; the filter cake was washed with anhydrous ethanol for 4 times, and dried at 70°C for 5 h to obtain modified graphene oxide;

[0051] (2) The polypropylene was irradiated by γ-rays with a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h, and the irradiated polypropylene, allyl phosphine dichloride, and anhydrous ethanol were mixed in a mass ratio of 1:0.15:50, stirred at 75°C and 250 r / min for 3.5 h under nitrogen atmosphere, filtered, and the filter residue was extracted with acetone for 48 h to obtain modified polypropylene;

[0052] (3) 2-chloromethylphenol, alkaline lignin, and 0.1 mol / L sodium hydroxide solution were mixed in a mass ratio of 1:1.5:15, stirred at 80°C and 250 r / min for 1.5 h, cooled to 60°C, and 2-chloromethylphenol was added with an equal molar amount of formaldehyde, reacted for 1.5 h, and then 0.5 times the molar amount of modified compound was added with formaldehyde, and the temperature was increased to 80°C for continuous reaction for 1.5 h; water was removed by rotary evaporation at 65°C to obtain a pre-modified lignin; 3-aminopyrrole, pre-modified lignin, sodium carbonate, and tetrahydrofuran were mixed in a mass ratio of 1:1.4:1.2:25, stirred at room temperature and 500 r / min for 4 h, filtered, and the filter residue was dried at 45°C for 6 h to obtain modified lignin;

[0053] (4) The modified lignin, modified graphene oxide, and modified polypropylene are mixed in a mass ratio of 1:1:10, and extruded and granulated by a twin-screw extruder, with the setting of the positions of each section being: head temperature 165℃, first zone temperature 170℃, second zone temperature 175℃, third zone temperature 180℃, and fourth zone temperature 175℃, and the length of the granules being 3.5mm, to obtain plastic granules; the plastic granules are treated by hot pressing by a hot press, with the hot pressing temperature being 150℃, the hot pressing time being 6min, the pressure being 4MPa, and then cold pressing at room temperature for 6min with the pressure being unchanged, to obtain the weather-resistant plastic.

[0054] Comparative Example 3

[0055] A preparation method of a weather-resistant plastic, comprising the following preparation steps:

[0056] (1) The polypropylene is irradiated by γ-rays with a radiation dose of 15kGy and a dose rate of 2.5kGy / h, and the irradiated polypropylene, allyl phosphine dichloride, and anhydrous ethanol are mixed in a mass ratio of 1:0.15:50, stirred at 75℃ and 250r / min for 3.5h under a nitrogen atmosphere, filtered, and the filter residue is extracted by acetone for 48h to obtain flame-retardant polypropylene; the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine, and tetrahydrofuran are mixed in a mass ratio of 1:0.25:0.2:35, stirred at room temperature and 250r / min for 8h under a nitrogen atmosphere, filtered, the filter cake is washed by anhydrous ethanol for 4 times, and dried at 70℃ for 5h to obtain modified polypropylene;

[0057] (2) 2-Chloromethyl phenol, alkali lignin, and 0.1mol / L sodium hydroxide solution are mixed in a mass ratio of 1:1.5:15, stirred at 80℃ and 250r / min for 1.5h, cooled to 60℃, 2-chloromethyl phenol is added in an equimolar amount of formaldehyde, reacted for 1.5h, 0.5 times the molar amount of modified compound is added to formaldehyde, heated to 80℃ and continued to react for 1.5h, and water is removed by rotary evaporation at 65℃ to obtain pre-modified lignin; 3-Aminopyrrole, pre-modified lignin, sodium carbonate, and tetrahydrofuran are mixed in a mass ratio of 1:1.4:1.2:25, stirred at room temperature and 500r / min for 4h, filtered, and the filter residue is dried at 45℃ for 6h to obtain modified lignin;

[0058] (3) The modified lignin, graphene oxide, and modified polypropylene are mixed in a mass ratio of 1:1:10, and extruded and granulated by a twin-screw extruder, with the setting of the positions of each section being: head temperature 165℃, first zone temperature 170℃, second zone temperature 175℃, third zone temperature 180℃, and fourth zone temperature 175℃, and the length of the granules being 3.5mm, to obtain plastic granules; the plastic granules are treated by hot pressing by a hot press, with the hot pressing temperature being 150℃, the hot pressing time being 6min, the pressure being 4MPa, and then cold pressing at room temperature for 6min with the pressure being unchanged, to obtain the weather-resistant plastic.

[0059] Comparative Example 4:

[0060] A preparation method of the weather-resistant plastic comprises the following preparation steps:

[0061] (1) 3-Aminopyrrole, anhydrous ethanol are mixed in a mass ratio of 1:45 to prepare an ethanol solution of 3-aminopyrrole; graphene oxide, deionized water are mixed in a mass ratio of 1:300 to prepare a graphene oxide suspension by ultrasonic dispersion, 3-aminopyrrole ethanol solution with a mass of 45 times that of graphene oxide is added, and stirring reflux is carried out at 90℃ and 250r / min for 22h, then the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare pyrrole modified graphene oxide; the pyrrole modified graphene oxide is formulated into a suspension with a concentration of 2.5mg / ml and treated by ultrasonic for 5h to prepare a pyrrole modified graphene oxide suspension; pyrrole, chloroform are mixed in a mass ratio of 1:30 to prepare a pyrrole chloroform solution; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride, chloroform are mixed in a mass ratio of 1:2:15, stirring is carried out at room temperature and 250r / min for 15min under nitrogen atmosphere, the temperature is lowered to 0℃, pyrrole chloroform solution with a mass of 15 times that of the pyrrole modified graphene oxide suspension is added, and stirring reaction is continued for 3h, then the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare modified graphene oxide;

[0062] (2) The irradiation dose of the polypropylene is 15kGy, and the dose rate is 2.5kGy / h, then the polypropylene is irradiated by γ-ray, and then the irradiated polypropylene, allyl phosphine dichloride, anhydrous ethanol are mixed in a mass ratio of 1:0.15:50, stirring is carried out at 75℃ and 250r / min for 3.5h under nitrogen atmosphere, then the filter residue is extracted with acetone for 48h to prepare flame-retardant polypropylene; the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine, tetrahydrofuran are mixed in a mass ratio of 1:0.25:0.2:35, stirring is carried out at room temperature and 250r / min for 8h under nitrogen atmosphere, then the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare modified polypropylene;

[0063] (3) The alkaline lignin, modified graphene oxide, modified polypropylene are mixed in a mass ratio of 1:1:10, and then extruded and granulated by a twin-screw extruder, the positions of each section are set as follows: the temperature of the die head is 165℃, the temperature of the first section is 170℃, the temperature of the second section is 175℃, the temperature of the third section is 180℃, the temperature of the fourth section is 175℃, and the length of the granules is 3.5mm, to prepare plastic granules; the plastic granules are treated by hot pressing with a hot press, the hot pressing temperature is 150℃, the hot pressing time is 6min, the pressure is 4MPa, and then the cold pressing is carried out at room temperature for 6min, and the pressure remains unchanged to prepare weather-resistant plastic.

[0064] Comparative Example 5:

[0065] A preparation method of weather-resistant plastic, comprising the following preparation steps:

[0066] (1) 3-Aminopyrrole, anhydrous ethanol are uniformly mixed in a mass ratio of 1:45 to prepare an ethanol solution of 3-aminopyrrole; graphene oxide, deionized water are uniformly mixed in a mass ratio of 1:300, and an ultrasonic dispersion is prepared to obtain a graphene oxide suspension, 3-aminopyrrole ethanol solution with a mass of 45 times that of graphene oxide is added, stirring at 90℃ and 250r / min for 22h, suction filtration, the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare pyrrole modified graphene oxide; the pyrrole modified graphene oxide is formulated into a suspension with a concentration of 2.5mg / ml and ultrasonic treated for 5h to prepare a pyrrole modified graphene oxide suspension; pyrrole, chloroform are uniformly mixed in a mass ratio of 1:30 to prepare a pyrrole chloroform solution; the pyrrole modified graphene oxide suspension, anhydrous ferric chloride, chloroform are uniformly mixed in a mass ratio of 1:2:15, stirring at room temperature and 250r / min for 15min under nitrogen atmosphere, cooling to 0℃, adding pyrrole chloroform solution with a mass of 15 times that of the pyrrole modified graphene oxide suspension, continuing to stir for 3h, suction filtration, the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare modified graphene oxide;

[0067] (2) The irradiated polypropylene, allyl phosphine dichloride, anhydrous ethanol are uniformly mixed in a mass ratio of 1:0.15:50, stirring at 75℃ and 250r / min for 3.5h under nitrogen atmosphere, filtering, and the filter residue is extracted with acetone for 48h to prepare flame-retardant polypropylene; the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine, tetrahydrofuran are uniformly mixed in a mass ratio of 1:0.25:0.2:35, stirring at room temperature and 250r / min for 8h under nitrogen atmosphere, suction filtration, the filter cake is washed with anhydrous ethanol for 4 times, and dried at 70℃ for 5h to prepare modified polypropylene;

[0068] (3) The modified graphene oxide, modified polypropylene are uniformly mixed in a mass ratio of 1:10, and are extruded and granulated by a double screw extruder, the positions of each section are set as follows: head temperature 165℃, first zone temperature 170℃, second zone temperature 175℃, third zone temperature 180℃, fourth zone temperature 175℃, and the particle length is 3.5mm to prepare plastic particles; the plastic particles are treated by hot pressing with a hot press, the hot pressing temperature is 150℃, the hot pressing time is 6min, the pressure is 4MPa, and the cold pressing time is 6min at room temperature, and the pressure remains unchanged to prepare weather-resistant plastic.

[0069] Test Example 1:

[0070] Mechanical property test: according to GB / T 1040-1992, the mechanical property of the sample was tested by using DXLL-5000 electronic tensile testing machine of Shanghai Dengjie Machinery Equipment Co., Ltd., and the test environment temperature was 25±1℃. The results are shown in Table 1.

[0071] Weather resistance test: according to GB / T3512-2014, the standard sample prepared was placed in a DHG-9245A type electric heating air drying oven for 30 days of indoor thermal aging test, and the temperature was set to 100℃. The tensile strength retention rate of the material after 30 days of aging test was tested. The results are shown in Table 2.

[0072] Self-repairing performance test: each example and the comparative example were cut into a sample with a specification of 20mmx4mmx1mm to prepare an original sample, and the original tensile strength 1 was tested. The sample was cut at the middle position, and the cut sample was gently placed together, heated to 150℃ and kept for 10min, and then cooled to room temperature. The tensile strength 2 was tested. The repair efficiency was calculated according to the repair efficiency=tensile strength 2 / tensile strength 1x100%. The results are shown in Table 3.

[0073] Table 1

[0074]

[0075] From the comparison of the experimental data of examples 1-3 and comparative examples 1-5 in Table 1, it can be found that the weather-resistant plastic prepared by the present application has good mechanical properties.

[0076] Through comparison, the tensile strength of examples 1-3 is greater than that of comparative example 2, which shows that the maleimide on the modified polypropylene can form stable chemical crosslinking with the pyrrole structure on the modified lignin through thermal reversible reaction, thereby improving the mechanical properties of the weather-resistant plastic; the tensile strength of examples 1-3 is greater than that of comparative example 3, which shows that the polypyrrole structure on the graphene oxide can form stable chemical crosslinking with the maleimide structure on the modified polypropylene through thermal reversible reaction, thereby improving the mechanical properties of the weather-resistant plastic; the tensile strength of examples 1-3 is greater than that of comparative example 4, which shows that the pyrrole structure on the modified lignin can form stable chemical crosslinking with the maleimide structure on the modified polypropylene through thermal reversible reaction, thereby improving the mechanical properties of the weather-resistant plastic.

[0077] Table 2

[0078]

[0079] From the comparison of the experimental data of examples 1-3 and comparative examples 1-5 in Table 2, it can be found that the weather-resistant plastic prepared by the present application has good weather resistance.

[0080] By comparison, the tensile strength retention rate of examples 1-3 is greater than that of comparative example 5, which indicates that the lignin contains rich phenolic hydroxyl structure, the phenolic hydroxyl structure can react with free radicals to capture the electrons of free radicals, thereby interrupting the chain reaction of free radicals, and effectively improving the aging resistance of the weather-resistant plastic.

[0081] Table 3

[0082]

[0083] From the comparison of the experimental data of examples 1-3 and comparative examples 1-5 in table 3, it can be found that the weather-resistant plastic prepared by the present application has good self-repairing performance.

[0084] By comparison, the repair efficiency of examples 1-3 is obviously greater than that of comparative example 2, which indicates that the maleimide structure on the modified polypropylene can occur thermal reversible reaction with polypyrrole on the modified graphene oxide and pyrrole on the modified lignin, high-temperature disconnection and low-temperature combination, so that the weather-resistant plastic can realize self-repairing effect under heating condition; the repair efficiency of examples 1-3 is greater than that of comparative example 3, which indicates that the polypyrrole structure on the graphene oxide can occur thermal reversible reaction with the maleimide structure on the modified polypropylene, thereby improving the self-repairing performance of the weather-resistant plastic; the repair efficiency of examples 1-3 is obviously greater than that of comparative examples 4 and 5, which indicates that the pyrrole on the modified lignin can occur thermal reversible reaction with the maleimide structure on the modified polypropylene, thereby improving the self-repairing performance of the weather-resistant plastic.

[0085] Test example 2:

[0086] Flame retardant performance test: according to ISO 4589-2 standard, the sample size is 100mm×6.5mm×3.2mm. The limiting oxygen index is tested by using JF-3 oxygen index instrument. The results are shown in table 4.

[0087] Table 4

[0088]

[0089] From the comparison of the experimental data of examples 1-3 and comparative examples 1-5 in table 4, it can be found that the weather-resistant plastic prepared by the present application has good flame retardant performance.

[0090] By comparison, the limiting oxygen index of examples 1-3 is obviously greater than that of comparative example 1, which indicates that the introduction of allyl phosphine dichloride on the polypropylene makes the weather-resistant plastic contain rich phosphorus element, and the phosphorus element has good flame retardant performance, thereby effectively improving the flame retardant performance of the weather-resistant plastic.

[0091] Test example 3:

[0092] Antistatic test: The antistatic performance test was carried out according to GB / T 1410-2006, the test voltage was 100V, the charging time was 30s, the sample was placed in a constant temperature and humidity chamber for 24h (23℃, relative humidity 45%) before the test, and the surface resistivity was tested. The results are shown in Table 5.

[0093] Table 5

[0094]

[0095] From the comparison of the experimental data of Examples 1-3 and Comparative Examples 1-5 in Table 5, it can be found that the weather-resistant plastic prepared by the present application has good antistatic performance.

[0096] Through comparison, the surface resistivity of Examples 1-3 is significantly smaller than that of Comparative Example 3, indicating that the polypyrrole is coated on the surface of graphene oxide, the polypyrrole has a large number of conjugated structures, and the conductive electrons can jump on the pyrrole ring of the conjugated structure, thereby improving the antistatic performance of the weather-resistant plastic.

[0097] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for the production of weatherable plastics, characterized in that The weather-resistant plastic is prepared by uniformly mixing modified lignin, modified graphene oxide and modified polypropylene, extruding and granulating, and hot-pressing molding; The modified lignin is prepared by reacting 2-chloromethyl phenol with alkaline lignin and formaldehyde to obtain pre-modified lignin, and reacting the pre-modified lignin with 3-aminopyrrole; The modified graphene oxide is prepared by reacting graphene oxide with an ethanol solution of 3-aminopyrrole to obtain pyrrole-modified graphene oxide, and reacting the pyrrole-modified graphene oxide with anhydrous ferric chloride and a chloroform solution of pyrrole; The modified polypropylene is prepared by reacting polypropylene treated by gamma ray irradiation with allyl phosphine dichloride, and then reacting the flame-retardant polypropylene with N-(4-hydroxyphenyl) maleimide and triethylamine; It is characterized by the following preparation steps: (1) uniformly mixing graphene oxide and deionized water at a mass ratio of 1:300, ultrasonic dispersion to obtain graphene oxide suspension, adding 40-50 times the mass of the graphene oxide of 3-aminopyrrole ethanol solution, stirring at 85-95 DEG C under 200-300 r / min for 20-24 h, suction filtration, washing the filter cake with anhydrous ethanol for 3-5 times, drying at 65-75 DEG C for 4-6 h to obtain pyrrole-modified graphene oxide; uniformly mixing pyrrole-modified graphene oxide suspension, anhydrous ferric chloride and chloroform at a mass ratio of 1:(1.5-2.5):(10-20), stirring at room temperature under nitrogen atmosphere for 10-20 min, cooling to 0 DEG C, adding 14-16 times the mass of the pyrrole-modified graphene oxide suspension of pyrrole chloroform solution, continuing to stir for 2.5-3.5 h, suction filtration, washing the filter cake with anhydrous ethanol for 3-5 times, drying at 65-75 DEG C for 4-6 h to obtain modified graphene oxide; (2) irradiating polypropylene with gamma rays at a radiation dose of 15 kGy and a dose rate of 2.5 kGy / h, uniformly mixing the irradiated polypropylene, allyl phosphine dichloride and anhydrous ethanol at a mass ratio of 1:(0.1-0.2):(40-60), stirring at 70-80 DEG C under nitrogen atmosphere at 200-300 r / min for 3-4 h, filtering, extracting the filter residue with acetone for 48 h to obtain flame-retardant polypropylene; uniformly mixing the flame-retardant polypropylene, N-(4-hydroxyphenyl) maleimide, triethylamine and tetrahydrofuran at a mass ratio of 1:(0.2-0.3):(0.15-0.25):(30-40), stirring at room temperature under nitrogen atmosphere at 200-300 r / min for 7-9 h, suction filtration, washing the filter cake with anhydrous ethanol for 3-5 times, drying at 65-75 DEG C for 4-6 h to obtain modified polypropylene; (3) mixing 2-chloromethyl phenol, alkaline lignin, 0.1 mol / L sodium hydroxide solution according to a mass ratio of 1:(1-2):(10-20), stirring at 75-85°C and 200-300 r / min for 1-2 h, cooling to 55-65°C, adding formaldehyde in an equal molar number of 2-chloromethyl phenol, reacting for 1-2 h, adding formaldehyde in a molar number of 0.5 times of the modified compound, increasing the temperature to 75-85°C and continuing to react for 1-2 h, removing water at 60-70°C by rotary evaporation, and preparing a pre-modified lignin; mixing 3-aminopyrrole, pre-modified lignin, sodium carbonate, and tetrahydrofuran according to a mass ratio of 1:(1.2-1.7):(1.1-1.3):(20-30), stirring at room temperature and 400-600 r / min for 3-5 h, filtering, and drying the filter residue at 40-50°C for 5-7 h to prepare a modified lignin; (4) mixing the modified lignin, modified graphene oxide, and modified polypropylene according to a mass ratio of 1:(0.8-1.2):(8-12), extruding and granulating by using a double-screw extruder to prepare plastic particles; and hot-pressing the plastic particles by using a hot press to prepare a weather-resistant plastic.

2. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (1), the graphene oxide has a diameter of 0.5-3 μm.

3. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (1), the preparation method of the 3-aminopyrrole ethanol solution is mixing 3-aminopyrrole and anhydrous ethanol according to a mass ratio of 1:(40-50) to prepare the 3-aminopyrrole ethanol solution; and the preparation method of the pyrrole chloroform solution is mixing pyrrole and chloroform according to a mass ratio of 1:30 to prepare the pyrrole chloroform solution.

4. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (2), the polypropylene is K8003 type polypropylene.

5. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (3), the alkaline lignin is an industrial-grade alkaline lignin.

6. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (4), the double-screw extrusion process parameters are: head temperature 165°C, zone 1 temperature 170°C, zone 2 temperature 175°C, zone 3 temperature 180°C, zone 4 temperature 175°C, and particle length 2-5 mm.

7. The method for preparing a weather-resistant plastic according to claim 1, characterized in that, In step (4), the hot-pressing process parameters are: hot-pressing temperature 150°C, hot-pressing time 6 min, pressure 4 MPa, cold-pressing temperature room temperature, cold-pressing time 6 min, and cold-pressing pressure 4 MPa.

8. Application of a weather-resistant plastic prepared by the preparation method of the weather-resistant plastic according to any one of claims 1-7 in a plastic part of an electric vehicle.

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