High-impact material prepared from recycled polypropylene and preparation method of high-impact material

Abstract

The invention discloses a high-impact material prepared from recycled polypropylene and a preparation method of the high-impact material, and relates to the field of materials. When recycled polypropylene is used for preparing the high-impact material, firstly, polypropylene is grafted with vinyl diphenylphosphine, then the grafted polypropylene is reacted with 1-(3-chlorphenyl)-2-propyn-1-ol, and then the reacted polypropylene is reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene; secondly, the calcium carbonate pretreated by 3-aminopropyltrimethoxysilane reacts with 3-thiophenecarboxaldehyde, thiophene, 6-(thiophene-2-yl) pyridine-2-carboxylic acid and 6-(3-thienyl) pyridine-2-formaldehyde are polymerized on the surface of the calcium carbonate, and modified calcium carbonate is obtained; and finally, carrying out melt blending on recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide, and carrying out extrusion granulation to obtain the high-impact material. The high-impact material prepared by the invention has good impact resistance, aging resistance and antibacterial property.

Description

Technical Field

[0001] The invention relates to the field of materials, and in particular to a high-impact material prepared by recycling polypropylene and a preparation method thereof. Background Art

[0002] Polypropylene, as the second most widely used general-purpose plastic in the world today, plays an important role in the production of various plastic products such as plastic buckets, plastic chairs, and plastic lunch boxes due to its excellent physical properties of low density, light weight, and stable chemical properties. It not only appears frequently in daily life, but also has a profound impact on the development of many industries such as construction, daily necessities, and packaging. However, with the vigorous development of these industries, the amount of waste polypropylene has also increased sharply, becoming one of the environmental problems that need to be solved urgently.

[0003] At present, there are various ways to deal with waste polypropylene, including landfill, incineration for energy, catalytic cracking to prepare fuel, and recycling. However, after weighing multiple factors such as technical feasibility, cost control, energy consumption, and environmental protection, recycling and reprocessing waste polypropylene into polymer materials is recognized as an environmentally friendly and sustainable treatment method.

[0004] However, the recycled waste polypropylene often comes from used plastic products. The mechanical properties of these plastics will inevitably weaken during use. At the same time, the additives or additives added during the processing may also migrate, further affecting the overall performance of the waste plastics. Therefore, in the process of recycling waste polypropylene, how to improve its mechanical properties so that it can meet the standards for reuse has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The object of the present invention is to provide a high-impact material prepared by recycling polypropylene and a preparation method thereof, so as to solve the problems existing in the prior art.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] The invention discloses a high-impact material prepared from recycled polypropylene. The high-impact material is prepared from recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide by melt blending and then extruding and granulating.

[0008] Preferably, the modified polypropylene is obtained by grafting vinyl diphenylphosphine onto polypropylene, reacting the grafted polypropylene with 1-(3-chlorophenyl)-2-propyn-1-ol, and reacting the grafted polypropylene with 6-(methyl formate)pyridine-3-boric acid.

[0009] Preferably, the modified calcium carbonate is obtained by reacting calcium carbonate pretreated with 3-aminopropyltrimethoxysilane with 3-thiophenecarboxaldehyde, and polymerizing thiophene, 6-(thiophen-2-yl)pyridine-2-carboxylic acid and 6-(3-thiophene)pyridine-2-carboxaldehyde on the surface of calcium carbonate.

[0010] A method for preparing a high-impact material by recycling polypropylene comprises the following steps:

[0011] (1) vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:(0.3-0.5):(20-30), and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 65-75 rpm, the temperature is 190-200° C., and the time is 10-12 min to obtain a primary product, and the primary product is dissolved in xylene with a mass of 50-60 times that of the primary product, heated to 130° C., stirred for 5-6 min, and the stirring speed is 200-300 r / min, and acetone is added in an equal volume to the volume of xylene, filtered and vacuum dried at 70-80° C. for 22-24 h to obtain phosphorus-containing polypropylene;

[0012] (2) mixing phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin in a mass ratio of 1:(0.5-0.6):(0.02-0.03):(20-30), heating to 140-150° C., reacting for 10-12 hours, and after the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene;

[0013] (3) reacting pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide at 80° C. under the condition of passing carbon monoxide for 18-20 hours, and after the reaction is completed, performing vacuum rotary evaporation to obtain modified polypropylene;

[0014] (4) Pretreated calcium carbonate, 3-thiophene carboxaldehyde, and acetone are mixed in a mass ratio of 1:(2-3):(20-30), ultrasonically dispersed uniformly, heated to 30-40° C. for reaction for 6-8 hours, filtered after the reaction is completed, washed with pure water for 3-4 times, and vacuum dried at 50-60° C. to obtain pre-modified calcium carbonate;

[0015] (5) Weigh the following components: pre-modified calcium carbonate, thiophene solution, 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 6-(3-thiophene)pyridine-2-carboxaldehyde solution, anhydrous ferric chloride, and chloroform; at 30-40° C., mix the pre-modified calcium carbonate, anhydrous ferric chloride, and chloroform for 30-40 min, add 40%-50% thiophene solution and stir for 1-2 h, add 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution and stir for 1-2 h, then add the remaining thiophene solution and stir for 1-2 h, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3-4 h. After stirring, filter and wash with pure water for 3-4 times to obtain modified calcium carbonate;

[0016] (6) Weigh the following raw materials by mass: 20-30 parts of recycled polypropylene, 50-60 parts of modified polypropylene, 6-10 parts of modified calcium carbonate, 0.2-0.3 parts of sodium cyanide, and 1-2 parts of bismaleimide, mix the raw materials and add them into a twin-screw extruder for blending and extrusion at a melting temperature of 190-200° C. After extrusion, send them into a pelletizer for granulation to obtain recycled polypropylene for preparing aging-resistant material.

[0017] Preferably, the model of the polypropylene in step (1) is 1102K.

[0018] Preferably, the pressure of carbon monoxide in step (3) is 5 bar.

[0019] Preferably, the preparation method of the pretreated calcium carbonate in step (4) is: 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water are mixed in a mass ratio of 1:1:5 for 10 minutes, 0.5 times the mass of the silane coupling agent is added into calcium carbonate, the temperature is raised to 110°C, refluxed for 3-4 hours, filtered and washed with anhydrous ethanol for 4 times, and vacuum dried to obtain the pretreated calcium carbonate.

[0020] Preferably, the thiophene solution in step (5) is obtained by mixing thiophene and chloroform in a mass ratio of 1:10; the 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution is obtained by mixing 6-(thiophene-2-yl)pyridine-2-carboxylic acid and chloroform in a mass ratio of 1:10; and the 6-(3-thienyl)pyridine-2-carboxaldehyde solution is obtained by mixing 6-(3-thienyl)pyridine-2-carboxaldehyde solution and chloroform in a mass ratio of 1:10.

[0021] Preferably, the weighed amounts of the components in step (5) are: by mass, 1 part of pre-modified calcium carbonate, 0.5 parts of thiophene solution, 0.1-0.2 parts of 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 0.1-0.3 parts of 6-(3-thienyl)pyridine-2-carboxaldehyde solution, 4-5 parts of anhydrous ferric chloride, and 20-30 parts of chloroform.

[0022] Preferably, the source of the recycled polypropylene in step (7) is crushed polypropylene lunch boxes, polypropylene plastic chairs, and polypropylene plastic barrels.

[0023] Preferably, the calcium carbonate has a specification of 1250 mesh.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] When the high-impact material is prepared by using recycled polypropylene, firstly, vinyl diphenylphosphine is grafted onto polypropylene, then the polypropylene is reacted with 1-(3-chlorophenyl)-2-propyn-1-ol, and then the polypropylene is reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene; secondly, calcium carbonate pretreated with 3-aminopropyltrimethoxysilane is reacted with 3-thiophenecarboxaldehyde, and thiophene, 6-(thiophene-2-yl) pyridine-2-carboxylic acid and 6-(3-thienyl) pyridine-2-carboxaldehyde are polymerized on the surface of calcium carbonate to obtain modified calcium carbonate; finally, the recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide are melt-blended and then extruded and granulated to obtain the high-impact material.

[0026] First, vinyl diphenylphosphine with flame retardant properties is grafted onto polypropylene to give the material good flame retardant properties. Second, the polypropylene is reacted with 1-(3-chlorophenyl)-2-propyn-1-ol. Chlorophenyl and phenylphosphine react to generate a quaternary phosphonium salt with antibacterial properties, which can give the material good antibacterial properties. The polypropylene is then reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene. The reaction of propynol and 6-(methyl formate) pyridine-3-boric acid can not only generate a furan structure, but also introduce a pyridine formaldehyde structure into the side chain of polypropylene.

[0027] Secondly, calcium carbonate, as an inorganic filler, can enhance the impact resistance of polypropylene. 3-aminopropyltrimethoxysilane is used to pretreat calcium carbonate so that the surface of calcium carbonate has amino groups. The surface of calcium carbonate has thiophene functional groups through the reaction of amino groups and 3-thiophenecarboxaldehyde. Thiophene, 6-(thiophene-2-yl)pyridine-2-carboxylic acid, and 6-(3-thiophene)pyridine-2-carboxaldehyde are polymerized on the surface of calcium carbonate with thiophene functional groups to obtain modified calcium carbonate. The conjugated structure of polythiophene can give the material good antistatic properties, prevent floating dust adsorption, and have certain self-cleaning properties. The negatively charged carboxylic acid functional group on 6-(thiophene-2-yl)pyridine-2-carboxylic acid allows calcium carbonate to be uniformly dispersed in polypropylene through electrostatic bonding. 6-(3-thiophene)pyridine-2-carboxaldehyde gives the surface of calcium carbonate a pyridinecarboxaldehyde structure.

[0028] Finally, the recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide are melt-blended and extruded and granulated to obtain a high-impact material. The furan structure on the polypropylene undergoes a Diels-Alder (DA) reaction in the presence of bismaleimide and is cross-linked by forming dynamic bonds. The breaking and recombination process of the dynamic bonds can dissipate a large amount of energy, thereby playing a role in buffering energy absorption and impact resistance. The pyridine aldehyde group on the modified polypropylene and modified calcium carbonate generates a pyridine enediol structure under the action of sodium cyanide. The pyridine enediol structure has good antioxidant and free radical scavenging capabilities. Its antioxidant mechanism is mainly based on its enediol structure. It provides hydrogen atoms or electrons to free radicals through multiple pathways such as direct hydrogen atom transfer, electron transfer with proton preferential loss, or electron transfer first followed by a proton transfer, forming a stable free radical intermediate, thereby effectively interrupting the free radical chain reaction and scavenging the free radical, giving the material good antioxidant ability. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The calcium carbonate used in the following embodiments and comparative examples has a specification of 1250 mesh; the recycled polypropylene used is sourced from a polypropylene lunch box; the model of the polypropylene is 1102K; the thiophene solution used is obtained by mixing thiophene and chloroform in a mass ratio of 1:10; the 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution used is obtained by mixing 6-(thiophene-2-yl)pyridine-2-carboxylic acid and chloroform in a mass ratio of 1:10; the 6-(3-thienyl)pyridine-2-carboxaldehyde solution used is obtained by mixing 6-(3-thienyl)pyridine-2-carboxaldehyde solution and chloroform in a mass ratio of 1:10.

[0031] Embodiment 1:

[0032] A high-impact material prepared by recycling polypropylene and a preparation method thereof, the preparation method comprising the following preparation steps:

[0033] (1) Vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:0.3:20, and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 75 rpm, the temperature is 200° C., and the time is 12 min to obtain a primary product, and the primary product is dissolved in xylene with a mass that is 60 times that of the primary product, heated to 130° C., stirred for 6 min, and the stirring speed is 300 r / min, and acetone with a volume equal to that of xylene is added, filtered and vacuum dried at 80° C. for 24 h to obtain phosphorus-containing polypropylene;

[0034] (2) mixing phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin in a mass ratio of 1:0.5:0.02:20, heating to 150° C., reacting for 12 hours, and after the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene;

[0035] (3) reacting pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide at 80° C., passing carbon monoxide, and a pressure of 5 bar for 20 hours. After the reaction is completed, performing vacuum rotary evaporation to obtain modified polypropylene;

[0036] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water were mixed at a mass ratio of 1:1:5 for 10 minutes, calcium carbonate 0.5 times the mass of the silane coupling agent was added, the temperature was raised to 110°C, refluxed for 4 hours, filtered and washed with anhydrous ethanol 4 times, and vacuum dried to obtain pretreated calcium carbonate; pretreated calcium carbonate, 3-thiophenecarboxaldehyde and acetone were mixed at a mass ratio of 1:2:20, ultrasonically dispersed uniformly, heated to 40°C for reaction for 8 hours, filtered after the reaction, washed with pure water 4 times, and vacuum dried at 60°C to obtain pre-modified calcium carbonate;

[0037] (5) Weigh the following components: 1 part of pre-modified calcium carbonate, 0.5 parts of thiophene solution, 0.1 parts of 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 0.1 parts of 6-(3-thiophene)pyridine-2-carboxaldehyde solution, 4 parts of anhydrous ferric chloride, and 20 parts of chloroform, by mass; at 40° C., mix the pre-modified calcium carbonate, anhydrous ferric chloride, and chloroform for 40 min, add 40% thiophene solution and stir for 2 h, add 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution and stir for 2 h, then add the remaining thiophene solution and stir for 2 h, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 4 h. After stirring, filter and wash with pure water 4 times to obtain modified calcium carbonate;

[0038] (6) Weigh the following raw materials by mass: 20 parts of recycled polypropylene, 50 parts of modified polypropylene, 6 parts of modified calcium carbonate, 0.2 parts of sodium cyanide, and 1 part of bismaleimide. Mix the raw materials and add them into a twin-screw extruder for blending and extrusion. The melting temperature is 200° C. After extrusion, the materials are sent to a pelletizer for pelletization to obtain recycled polypropylene for preparing an aging-resistant material.

[0039] Embodiment 2:

[0040] A high-impact material prepared by recycling polypropylene and a preparation method thereof, the preparation method comprising the following preparation steps:

[0041] (1) Vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:0.4:25, and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 70 rpm, the temperature is 195° C., and the time is 11 min to obtain a primary product, and the primary product is dissolved in xylene with a mass of 55 times that of the primary product, heated to 130° C., stirred for 5 min, and stirred at a speed of 250 r / min, and acetone of an equal volume to that of xylene is added, filtered and vacuum dried at 75° C. for 23 h to obtain phosphorus-containing polypropylene;

[0042] (2) mixing phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin in a mass ratio of 1:0.55:0.025:25, heating to 145° C., reacting for 11 hours, and after the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene;

[0043] (3) reacting pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide at 80° C., passing carbon monoxide, and a pressure of 5 bar for 19 hours. After the reaction is completed, performing vacuum rotary evaporation to obtain modified polypropylene;

[0044] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water were mixed at a mass ratio of 1:1:5 for 10 minutes, calcium carbonate 0.5 times the mass of the silane coupling agent was added, the temperature was raised to 110°C, refluxed for 3.5 hours, filtered and washed with anhydrous ethanol 4 times, and vacuum dried to obtain pretreated calcium carbonate; pretreated calcium carbonate, 3-thiophenecarboxaldehyde and acetone were mixed at a mass ratio of 1:2.5:25, ultrasonically dispersed uniformly, heated to 35°C for reaction for 7 hours, filtered after the reaction, washed with pure water 3 times, and vacuum dried at 55°C to obtain pre-modified calcium carbonate;

[0045] (5) Weigh the following components: 1 part of pre-modified calcium carbonate, 0.5 parts of thiophene solution, 0.15 parts of 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 0.2 parts of 6-(3-thiophene)pyridine-2-carboxaldehyde solution, 4.5 parts of anhydrous ferric chloride, and 25 parts of chloroform, by mass. At 35° C., mix the pre-modified calcium carbonate, anhydrous ferric chloride, and chloroform for 35 minutes, add 45% thiophene solution and stir for 1.5 hours, add 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution and stir for 1.5 hours, then add the remaining thiophene solution and stir for 1.5 hours, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3.5 hours. After stirring, filter and wash with pure water three times to obtain modified calcium carbonate.

[0046] (6) Weigh the following raw materials by mass: 25 parts of recycled polypropylene, 55 parts of modified polypropylene, 8 parts of modified calcium carbonate, 0.25 parts of sodium cyanide, and 1.5 parts of bismaleimide. Mix the raw materials and add them into a twin-screw extruder for blending and extrusion. The melting temperature is 195° C. After extrusion, the materials are sent to a pelletizer for pelletization to obtain recycled polypropylene for preparing an aging-resistant material.

[0047] Embodiment 3:

[0048] A high-impact material prepared by recycling polypropylene and a preparation method thereof, the preparation method comprising the following preparation steps:

[0049] (1) vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:0.5:30, and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 65 rpm, the temperature is 1900° C., and the time is 10 min to obtain a primary product, and the primary product is dissolved in xylene with a mass that is 60 times that of the primary product, heated to 130° C., stirred for 5 min, and the stirring speed is 200 r / min, and acetone with a volume equal to that of xylene is added, filtered and vacuum dried at 70° C. for 22 h to obtain phosphorus-containing polypropylene;

[0050] (2) mixing phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin in a mass ratio of 1:0.6:0.03:30, heating to 140° C., reacting for 10 hours, and after the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene;

[0051] (3) reacting pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide at 80° C., passing carbon monoxide, and a pressure of 5 bar for 18 hours. After the reaction is completed, performing vacuum rotary evaporation to obtain modified polypropylene;

[0052] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water were mixed at a mass ratio of 1:1:5 for 10 minutes, calcium carbonate with a mass of 0.5 times of the silane coupling agent was added, the temperature was raised to 110°C, refluxed for 3 hours, filtered and washed with anhydrous ethanol 4 times, and vacuum dried to obtain pretreated calcium carbonate; pretreated calcium carbonate, 3-thiophenecarboxaldehyde and acetone were mixed at a mass ratio of 1:3:30, ultrasonically dispersed uniformly, heated to 30°C for reaction for 6 hours, filtered after the reaction, washed with pure water 3 times, and vacuum dried at 50°C to obtain pre-modified calcium carbonate;

[0053] (5) Weigh the following components: 1 part of pre-modified calcium carbonate, 0.5 parts of thiophene solution, 0.2 parts of 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 0.3 parts of 6-(3-thiophene)pyridine-2-carboxaldehyde solution, 5 parts of anhydrous ferric chloride, and 30 parts of chloroform, by mass. At 30° C., mix the pre-modified calcium carbonate, anhydrous ferric chloride, and chloroform for 30 min, add 50% of the thiophene solution and stir for 1 h, add 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution and stir for 1 h, then add the remaining thiophene solution and stir for 1 h, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3 h. After stirring, filter and wash with pure water 3 times to obtain modified calcium carbonate.

[0054] (6) Weigh the following raw materials by mass: 30 parts of recycled polypropylene, 60 parts of modified polypropylene, 10 parts of modified calcium carbonate, 0.3 parts of sodium cyanide, and 2 parts of bismaleimide. Mix the raw materials and add them into a twin-screw extruder for blending and extrusion. The melting temperature is 190° C. After extrusion, the materials are sent to a pelletizer for pelletization to obtain recycled polypropylene for preparing an aging-resistant material.

[0055] Comparative Example 1:

[0056] The preparation method of high-impact material prepared by recycling polypropylene in Comparative Example 1 differs from that in Example 2 in that it does not contain steps (2) and (3), and step (1) is modified as follows: vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:0.4:25, and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 70 rpm, the temperature is 195° C., and the time is 11 min to obtain a primary product, and the primary product is dissolved in xylene with a mass 55 times that of the primary product, heated to 130° C., stirred for 5 min, and stirred at a speed of 250 r / min, and acetone of an equal volume to that of xylene is added, filtered and vacuum dried at 75° C. for 23 h to obtain modified polypropylene.

[0057] Comparative Example 2:

[0058] The difference between the preparation method of high-impact material prepared by recycled polypropylene in Comparative Example 2 and Example 2 is that step (6) is modified as follows: weigh the following raw materials in parts by mass: 25 parts of recycled polypropylene, 55 parts of modified polypropylene, 8 parts of modified calcium carbonate, and 0.25 parts of sodium cyanide; mix the raw materials and add them to a twin-screw extruder for blending and extrusion; the melting temperature is 195°C; after extrusion, send them to a pelletizer for granulation to obtain recycled polypropylene for preparing aging-resistant material.

[0059] Comparative Example 3:

[0060] The difference between the preparation method of high-impact material prepared by recycled polypropylene in Comparative Example 3 and Example 2 is that step (6) is modified as follows: weigh the following raw materials by mass: 25 parts of recycled polypropylene, 55 parts of modified polypropylene, 8 parts of modified calcium carbonate, and 1.5 parts of bismaleimide, mix the raw materials and add them into a twin-screw extruder for blending and extrusion, the melting temperature is 195° C., and after extrusion, send them into a pelletizer for granulation to obtain recycled polypropylene for preparing aging-resistant material;

[0061] Test Example 1:

[0062] Mechanical properties test:

[0063] The materials obtained in the examples and comparative examples were cut into samples with a size of 20 mm*10 mm, and the samples were subjected to impact strength tests according to the standard GB / T1043.1-2008, with a span of 70 mm, an impact speed of 3.8 m / s, and a pendulum pre-elevation angle of 150°. The results are shown in Table 1.

[0064] Thermal oxygen aging resistance test:

[0065] Test method: According to the standard GB / T 1040-2006, the recycled polypropylene prepared in the embodiment and the comparative example is used to prepare the high impact material to prepare the sample, the sample is laid flat on the sample rack, and then put into the aging box, the aging temperature is 50°C, the relative humidity is 55%, the ozone concentration is 450pphm, the aging time is 180h, and after the aging is completed, the tensile strength retention rate is calculated according to the mechanical property test method. The results are shown in Table 1.

[0066] Table 1 Statistics of mechanical properties test results

[0067] <![CDATA[Impact strength (KJ / m 2 )]]> Impact strength retention rate (%) Example 1 81.13 95.36 Example 2 81.27 95.37 Example 3 82.24 95.41 Comparative Example 1 51.67 69.23 Comparative Example 2 62.31 93.56 Comparative Example 3 75.31 71.22

[0068] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 1, it can be found that the high-impact material prepared from the recycled polypropylene prepared in the present invention has good impact resistance and anti-aging properties.

[0069] By comparison, the impact strength of Examples 1 to 3 is greater than that of Comparative Examples 1 to 3, and the impact strength retention rate of Examples 1 to 3 after thermal oxidative aging is greater than that of Comparative Examples 1 and 3 after thermal oxidative aging; this indicates that calcium carbonate, as an inorganic filler, can enhance the impact resistance of polypropylene, and that the recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide, and bismaleimide are melt-blended and then extruded and granulated to obtain a high-impact material; the furan structure on the polypropylene undergoes a Diels-Alder (DA) reaction in the presence of bismaleimide, and cross-links are formed by forming dynamic bonds, and the rupture and recombination of the dynamic bonds. The formation process can dissipate a large amount of energy, thereby playing a role in buffering energy absorption and impact resistance; the pyridine aldehyde group on modified polypropylene and modified calcium carbonate generates a pyridine enediol structure under the action of sodium cyanide. The pyridine enediol structure has good antioxidant and free radical scavenging capabilities. Its antioxidant mechanism is mainly based on its 2-enediol structure. It provides hydrogen atoms or electrons to free radicals through multiple pathways such as direct hydrogen atom transfer, electron transfer with proton preferential loss, or electron transfer followed by a proton transfer, forming stable free radical intermediates, thereby effectively interrupting the free radical chain reaction and scavenging free radicals, giving the material good antioxidant ability.

[0070] Test Example 2:

[0071] Antibacterial performance test:

[0072] Test method: The recycled polypropylene high-impact material prepared in the embodiment and the comparative example was prepared into a 6 mm circular sheet; the circular sheet was placed on an agar medium coated with bacterial solution, inverted in a constant temperature incubator at 37°C for culture, taken out after 24 hours, and the diameter of the inhibition zone was measured and recorded. Staphylococcus aureus was selected as the bacterial solution, and the larger the diameter, the better the antibacterial performance. The results are shown in Table 2.

[0073] Table 2 Statistics of antibacterial performance test results

[0074] Diameter of inhibition zone / mm Diameter of inhibition zone / mm Example 1 11.2 Comparative Example 1 3.5 Example 2 11.3 Comparative Example 2 11.1 Example 3 11.3 Comparative Example 3 11.1

[0075] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 3 in Table 2, it can be found that the high-impact material prepared from the recycled polypropylene prepared in the present invention has good antibacterial properties.

[0076] By comparison, the antibacterial properties of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that first, polypropylene is grafted with vinyl diphenyl phosphine, which is then reacted with 1-(3-chlorophenyl)-2-propyn-1-ol, and the chlorophenyl group and phenyl phosphine react to generate a quaternary phosphonium salt with antibacterial properties, which can give the material good antibacterial properties.

[0077] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing high impact material by recycling polypropylene, characterized in that: The high-impact material prepared from recycled polypropylene is prepared by melt blending recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide, followed by extrusion granulation. The modified polypropylene is obtained by grafting vinyl diphenylphosphine onto polypropylene, reacting with 1-(3-chlorophenyl)-2-propyn-1-ol, and then reacting with 6-(methyl formate)pyridine-3-boric acid; The modified calcium carbonate is obtained by reacting calcium carbonate pretreated with 3-aminopropyltrimethoxysilane with 3-thiophenecarboxaldehyde, and polymerizing thiophene, 6-(thiophene-2-yl)pyridine-2-carboxylic acid and 6-(3-thiophene-yl)pyridine-2-carboxaldehyde on the surface of calcium carbonate.

2. A method for preparing high impact material by recycling polypropylene, characterized in that: The method comprises the following preparation steps: (1) vinyl diphenylphosphine, di-tert-butyl peroxide isopropylbenzene and polypropylene are mixed in a mass ratio of 1:(0.3-0.5):(20-30), and melt grafting is performed using a Haake rheometer, wherein the Haake rheometer speed is 65-75 rpm, the temperature is 190-200° C., and the time is 10-12 min to obtain a primary product, and the primary product is dissolved in xylene with a mass of 50-60 times that of the primary product, heated to 130° C., stirred for 5-6 min, and the stirring speed is 200-300 r / min, and acetone is added in an equal volume to the volume of xylene, filtered and vacuum dried at 70-80° C. for 22-24 h to obtain phosphorus-containing polypropylene; (2) mixing phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin in a mass ratio of 1:(0.5-0.6):(0.02-0.03):(20-30), heating to 140-150° C., reacting for 10-12 hours, and after the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene; (3) reacting pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide at 80° C. under the condition of passing carbon monoxide for 18-20 hours, and after the reaction is completed, performing vacuum rotary evaporation to obtain modified polypropylene; (4) Pretreated calcium carbonate, 3-thiophene carboxaldehyde, and acetone are mixed in a mass ratio of 1:(2-3):(20-30), ultrasonically dispersed uniformly, heated to 30-40° C. for reaction for 6-8 hours, filtered after the reaction is completed, washed with pure water for 3-4 times, and vacuum dried at 50-60° C. to obtain pre-modified calcium carbonate; (5) Weigh the following components: pre-modified calcium carbonate, thiophene solution, 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 6-(3-thiophene)pyridine-2-carboxaldehyde solution, anhydrous ferric chloride, and chloroform; at 30-40° C., mix the pre-modified calcium carbonate, anhydrous ferric chloride, and chloroform for 30-40 min, add 40%-50% thiophene solution and stir for 1-2 h, add 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution and stir for 1-2 h, then add the remaining thiophene solution and stir for 1-2 h, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3-4 h. After stirring, filter and wash with pure water for 3-4 times to obtain modified calcium carbonate; (6) Weigh the following raw materials by mass: 20-30 parts of recycled polypropylene, 50-60 parts of modified polypropylene, 6-10 parts of modified calcium carbonate, 0.2-0.3 parts of sodium cyanide, and 1-2 parts of bismaleimide, mix the raw materials and add them into a twin-screw extruder for blending and extrusion at a melting temperature of 190-200° C. After extrusion, send them into a pelletizer for granulation to obtain recycled polypropylene for preparing aging-resistant material.

3. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The model of the polypropylene in step (1) is 1102K.

4. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The pressure of carbon monoxide in step (3) is 5 bar.

5. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The preparation method of the pretreated calcium carbonate in step (4) is as follows: 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water are mixed in a mass ratio of 1:1:5 for 10 minutes, 0.5 times the mass of the silane coupling agent of calcium carbonate is added, the temperature is raised to 110° C., refluxed for 3-4 hours, filtered and washed with anhydrous ethanol for 4 times, and vacuum dried to obtain the pretreated calcium carbonate.

6. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The thiophene solution in step (5) is obtained by mixing thiophene and chloroform in a mass ratio of 1:10; the 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution is obtained by mixing 6-(thiophene-2-yl)pyridine-2-carboxylic acid and chloroform in a mass ratio of 1:10; and the 6-(3-thienyl)pyridine-2-carboxaldehyde solution is obtained by mixing 6-(3-thienyl)pyridine-2-carboxaldehyde solution and chloroform in a mass ratio of 1:

10.

7. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The weighed amounts of the components in step (5) are: 1 part of pre-modified calcium carbonate, 0.5 parts of thiophene solution, 0.1-0.2 parts of 6-(thiophene-2-yl)pyridine-2-carboxylic acid solution, 0.1-0.3 parts of 6-(3-thienyl)pyridine-2-carboxaldehyde solution, 4-5 parts of anhydrous ferric chloride, and 20-30 parts of chloroform, by mass.

8. The method for preparing high impact material by recycling polypropylene according to claim 2, characterized in that: The source of the recycled polypropylene in step (7) is one or more of polypropylene lunch boxes, polypropylene plastic chairs, and polypropylene plastic barrel crushed materials.

9. The method for preparing high impact material by recycling polypropylene according to claim 4, characterized in that: The calcium carbonate specification is 1250 mesh.