A high-impact material prepared by recycling polypropylene and its preparation method

Abstract

The invention discloses a kind of recycling polypropylene to prepare high-impact material and preparation method thereof, relate to the field of materials. When the present invention uses recycling polypropylene to prepare high-impact material, first, polypropylene is grafted with vinyl diphenylphosphine, then reacted with 1-(3-chlorophenyl)-2-propyn-1-ol, and then reacted with 6-(methyl formate) pyridine-3-boric acid to obtain modified polypropylene; Secondly, calcium carbonate pretreated with 3-aminopropyltrimethoxysilane and 3-thiophene carboxaldehyde are reacted, 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, recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide, and bismaleimide are melt-blended, and then extrusion granulation is performed to obtain high-impact material; The high-impact material prepared by the present invention has good impact resistance, anti-aging performance and antibacterial performance.

Description

Technical Field

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

[0002] Polypropylene, the second most widely used general-purpose plastic worldwide, plays a crucial role in the production of a wide range of plastic products, including plastic buckets, chairs, and lunch boxes, thanks to its outstanding physical properties: low density, light weight, and stable chemical properties. Not only is it a common sight in daily life, it also profoundly impacts the development of numerous industries, including construction, household goods, and packaging. However, with the booming development of these industries, the amount of waste polypropylene has also surged, becoming a pressing environmental issue.

[0003] Currently, there are various methods for disposing of waste polypropylene, including landfill, incineration for energy, catalytic cracking to produce fuel, and recycling. However, after weighing multiple factors, including 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, recycled waste polypropylene often comes from used plastic products. The mechanical properties of these plastics inevitably weaken during use. Furthermore, additives added during processing can migrate, further impacting the overall performance of the waste plastic. Therefore, improving the mechanical properties of waste polypropylene to meet reuse standards in the recycling process has become a pressing technical challenge. Summary of the Invention

[0005] The purpose 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 by melt-blending recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide and bismaleimide, and then extruding and granulating the mixture.

[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-thienyl)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 isopropyl benzene, 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 amount equal 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 completion of the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene;

[0013] (3) Pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide were reacted at 80° C. under the condition of carbon monoxide flow for 18-20 hours. After the reaction was completed, the modified polypropylene was obtained by vacuum rotary evaporation;

[0014] (4) Pretreated calcium carbonate, 3-thiophene carboxaldehyde, and acetone were mixed in a mass ratio of 1:(2-3):(20-30), ultrasonically dispersed uniformly, heated to 30-40°C for reaction for 6-8h, filtered after the reaction, washed with pure water 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-(thiophen-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 minutes, add 40%-50% thiophene solution and stir for 1-2 hours, add 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution and stir for 1-2 hours, then add the remaining thiophene solution and stir for 1-2 hours, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3-4 hours. After stirring, filter and wash with pure water 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. The melting temperature is 190-200°C. After extrusion, the materials are sent to 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: mixing 3-aminopropyltrimethoxysilane, anhydrous ethanol and pure water in a mass ratio of 1:1:5 for 10 minutes, adding calcium carbonate 0.5 times the mass of the silane coupling agent, heating to 110°C, reflux reaction for 3-4 hours, filtering and washing with anhydrous ethanol 4 times, and vacuum drying to obtain 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-(thiophen-2-yl)pyridine-2-carboxylic acid solution is obtained by mixing 6-(thiophen-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: 1 part of pre-modified calcium carbonate, 0.5 part of thiophene solution, 0.1-0.2 part of 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution, 0.1-0.3 part of 6-(3-thienyl)pyridine-2-carboxaldehyde solution, 4-5 parts of anhydrous ferric chloride, and 20-30 parts of chloroform, by mass.

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

[0023] Preferably, the calcium carbonate specification is 1250 mesh.

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

[0025] When using recycled polypropylene to prepare a high-impact material, the present invention comprises the following steps: first, vinyl diphenylphosphine is grafted onto polypropylene, followed by reaction with 1-(3-chlorophenyl)-2-propyn-1-ol, and then with 6-(methyl formate)pyridine-3-boric acid to obtain modified polypropylene; second, calcium carbonate pretreated with 3-aminopropyltrimethoxysilane is reacted with 3-thiophenecarboxaldehyde, and thiophene, 6-(thiophen-2-yl)pyridine-2-carboxylic acid, and 6-(3-thienyl)pyridine-2-carboxaldehyde are polymerized on the surface of the calcium carbonate to obtain modified calcium carbonate; and 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, polypropylene is grafted with flame-retardant vinyl diphenylphosphine to impart good flame-retardant properties. Then, the grafted polypropylene is reacted with 1-(3-chlorophenyl)-2-propyn-1-ol. The chlorophenyl group and phenylphosphine react to form a quaternary phosphonium salt with antibacterial properties, which imparts good antibacterial properties to the material. The grafted polypropylene is then reacted with 6-(methyl formate)pyridine-3-boronic acid to obtain modified polypropylene. The reaction of propynol with 6-(methyl formate)pyridine-3-boronic acid not only generates a furan structure but also introduces a pyridine formaldehyde structure into the polypropylene side chain.

[0027] Secondly, calcium carbonate, as an inorganic filler, can enhance the impact resistance of polypropylene. Calcium carbonate is pretreated with 3-aminopropyltrimethoxysilane to impart amino groups to the surface of the calcium carbonate. The amino groups react with 3-thiophenecarboxaldehyde to impart thiophene functional groups to the surface of the calcium carbonate. Thiophene, 6-(thiophen-2-yl)pyridine-2-carboxylic acid, and 6-(3-thiophene)pyridine-2-carboxaldehyde are polymerized on the surface of the calcium carbonate with thiophene functional groups to obtain modified calcium carbonate. The conjugated structure of polythiophene can impart good antistatic properties to the material, preventing dust adsorption and imparting certain self-cleaning properties. The negatively charged carboxylic acid functional groups on 6-(thiophen-2-yl)pyridine-2-carboxylic acid allow calcium carbonate to be uniformly dispersed in polypropylene through electrostatic bonding. 6-(3-thiophene)pyridine-2-carboxaldehyde imparts a pyridinecarboxaldehyde structure to the surface of the calcium carbonate.

[0028] Finally, recycled polypropylene, modified polypropylene, modified calcium carbonate, sodium cyanide, and bismaleimide are melt-blended and then extruded and granulated to produce a high-impact material. The furan structure on the polypropylene undergoes a Diels-Alder (DA) reaction in the presence of bismaleimide, and cross-links 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. Through multiple pathways such as direct hydrogen atom transfer, electron transfer with proton preferential loss, or electron transfer followed by a proton transfer, it provides hydrogen atoms or electrons to the free radicals to form stable free radical intermediates, thereby effectively interrupting the free radical chain reaction and scavenging the free radicals, 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 embodiments described 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 making creative efforts are within the scope of protection of the present invention.

[0030] The calcium carbonate used in the following examples and comparative examples has a specification of 1250 mesh; the recycled polypropylene used is sourced from polypropylene lunch boxes; 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-(thiophen-2-yl)pyridine-2-carboxylic acid solution used is obtained by mixing 6-(thiophen-2-yl)pyridine-2-carboxylic acid and chloroform in a mass ratio of 1:10; and 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] Example 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 isopropyl benzene, and polypropylene are mixed in a mass ratio of 1:0.3:20, and melt grafted using a Hake rheometer at a speed of 75 rpm, a temperature of 200° C., and a time of 12 min to obtain a primary product, which is dissolved in xylene with a mass 60 times that of the primary product, heated to 130° C., stirred for 6 min at a stirring speed of 300 r / min, and an acetone equal in volume to the xylene is added, filtered, and vacuum dried at 80° C. for 24 h to obtain phosphorus-containing polypropylene;

[0034] (2) Phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin were mixed in a mass ratio of 1:0.5:0.02:20, heated to 150° C., and reacted for 12 h. After the reaction was completed, pre-modified polypropylene was obtained by vacuum rotary evaporation;

[0035] (3) Pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide were reacted at 80° C. under the conditions of carbon monoxide and a pressure of 5 bar for 20 hours. After the reaction was completed, the modified polypropylene was obtained by vacuum rotary evaporation;

[0036] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol, and pure water were mixed in a mass ratio of 1:1:5 for 10 minutes, and calcium carbonate 0.5 times the mass of the silane coupling agent was added, and the mixture was heated 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 in a mass ratio of 1:2:20, ultrasonically dispersed, heated to 40°C for 8 hours, filtered, 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-(thiophen-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 minutes, add 40% of the thiophene solution and stir for 2 hours, add the 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution and stir for 2 hours, then add the remaining thiophene solution and stir for 2 hours, then add the 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 4 hours. 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 granulation to obtain recycled polypropylene for preparing aging-resistant material.

[0039] Example 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 isopropyl benzene, and polypropylene were mixed in a mass ratio of 1:0.4:25, and melt grafted using a Hake rheometer at a speed of 70 rpm, a temperature of 195° C., and a time of 11 minutes to obtain a primary product, which was dissolved in xylene with a mass 55 times that of the primary product, heated to 130° C., stirred for 5 minutes at a stirring speed of 250 r / min, and acetone of an equal volume to that of xylene was added, filtered, and vacuum dried at 75° C. for 23 hours to obtain phosphorus-containing polypropylene;

[0042] (2) Phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin were mixed in a mass ratio of 1:0.55:0.025:25, heated to 145° C., and reacted for 11 hours. After the reaction was completed, pre-modified polypropylene was obtained by vacuum rotary evaporation;

[0043] (3) Pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide were reacted at 80° C. under the conditions of carbon monoxide and a pressure of 5 bar for 19 hours. After the reaction, the modified polypropylene was obtained by vacuum rotary evaporation;

[0044] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol, and pure water were mixed in a mass ratio of 1:1:5 for 10 minutes, and calcium carbonate 0.5 times the mass of the silane coupling agent was added, and the mixture was heated to 110°C, refluxed for 3.5 hours, filtered, and washed with anhydrous ethanol four times, and vacuum dried to obtain pretreated calcium carbonate; pretreated calcium carbonate, 3-thiophenecarboxaldehyde, and acetone were mixed in a mass ratio of 1:2.5:25, ultrasonically dispersed, heated to 35°C for 7 hours, filtered, washed with pure water three 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-(thiophen-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-(thiophen-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 granulation to obtain recycled polypropylene for preparing aging-resistant material.

[0047] Example 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 isopropyl benzene, and polypropylene are mixed in a mass ratio of 1:0.5:30, and melt grafted using a Haake rheometer at a speed of 65 rpm, a temperature of 1900° C., and a time of 10 min to obtain a primary product, which is dissolved in xylene with a mass 60 times that of the primary product, heated to 130° C., stirred for 5 min at a stirring speed of 200 r / min, and an acetone equal in volume to the xylene is added, filtered, and vacuum dried at 70° C. for 22 h to obtain phosphorus-containing polypropylene;

[0050] (2) Phosphorus-containing polypropylene, 1-(3-chlorophenyl)-2-propyn-1-ol, potassium iodide, and decalin were mixed in a mass ratio of 1:0.6:0.03:30, heated to 140° C., and reacted for 10 h. After the reaction was completed, pre-modified polypropylene was obtained by vacuum rotary evaporation;

[0051] (3) Pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide were reacted at 80° C. under the conditions of carbon monoxide and a pressure of 5 bar for 18 hours. After the reaction was completed, the modified polypropylene was obtained by vacuum rotary evaporation;

[0052] (4) 3-aminopropyltrimethoxysilane, anhydrous ethanol, and pure water were mixed in a mass ratio of 1:1:5 for 10 minutes, and calcium carbonate 0.5 times the mass of the silane coupling agent was added, and the mixture was heated 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 in a mass ratio of 1:3:30, ultrasonically dispersed, heated to 30°C for 6 hours, filtered, 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-(thiophen-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 minutes, add 50% of the thiophene solution and stir for 1 hour, add the 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution and stir for 1 hour, then add the remaining thiophene solution and stir for 1 hour, then add the 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3 hours. 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 granulation to obtain recycled polypropylene for preparing aging-resistant materials.

[0055] Comparative Example 1:

[0056] The preparation method of the high-impact material prepared by recycling polypropylene in Comparative Example 1 differs from that in Example 2 in that steps (2) and (3) are not included, and step (1) is modified as follows: vinyl diphenylphosphine, di-tert-butyl peroxide isopropyl benzene, 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, which 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 with a volume equal 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 from 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, the materials are sent 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 the high-impact material prepared from recycled polypropylene in Comparative Example 3 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 1.5 parts of bismaleimide, mix the raw materials and add them to a twin-screw extruder for blending and extrusion at a melting temperature of 195°C. After extrusion, the materials are sent to a pelletizer for granulation to obtain the recycled polypropylene for preparing the aging-resistant material;

[0061] Test Example 1:

[0062] Mechanical properties test:

[0063] The materials prepared in the Examples and Comparative Examples were cut into 20 mm x 10 mm specimens and subjected to impact strength testing according to standard GB / T 1043.1-2008, with a span of 70 mm, an impact velocity 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: Samples of high-impact materials prepared from recycled polypropylene obtained in the Examples and Comparative Examples were prepared in accordance with GB / T 1040-2006. The samples were laid flat on a sample rack and placed in an aging chamber at 50°C, 55% relative humidity, and an ozone concentration of 450 pphm for 180 hours. After aging, the materials were tested according to the mechanical properties test method and the tensile strength retention was calculated. 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; this indicates that calcium carbonate, as an inorganic filler, can enhance the impact resistance of polypropylene. 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. The rupture and recombination of the dynamic bonds The group 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 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 2-enediol structure. Through direct hydrogen atom transfer, electron transfer with proton preferential loss, or electron transfer followed by a proton transfer and other pathways, it provides hydrogen atoms or electrons to free radicals to form 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] Testing method: The high-impact materials made from recycled polypropylene obtained in the Examples and Comparative Examples were shaped into 6 mm circular slices. These slices were placed on agar culture medium coated with a bacterial solution and incubated upside down in a 37°C constant-temperature incubator. After 24 hours, the slices were removed and the diameter of the inhibition zone was measured and recorded. Staphylococcus aureus was selected for the bacterial solution. A larger diameter indicates better antibacterial performance. The results are shown in Table 2.

[0073] Table 2 Statistics of antibacterial performance test results

[0074] Inhibition zone diameter / mm Inhibition zone diameter / 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, vinyl diphenylphosphine is grafted onto polypropylene, which is then reacted with 1-(3-chlorophenyl)-2-propyn-1-ol, and the chlorophenyl group and phenylphosphine react to form 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 materials 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 the grafted vinyl diphenylphosphine with 1-(3-chlorophenyl)-2-propyn-1-ol, and reacting the grafted vinyl diphenylphosphine 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-(thiophen-2-yl)pyridine-2-carboxylic acid and 6-(3-thienyl)pyridine-2-carboxaldehyde on the surface of the calcium carbonate.

2. A method for preparing high-impact materials by recycling polypropylene, characterized in that: The method comprises the following preparation steps: (1) vinyl diphenylphosphine, di-tert-butyl peroxide isopropyl benzene, 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 amount equal 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 completion of the reaction, performing vacuum rotary evaporation to obtain pre-modified polypropylene; (3) Pre-modified polypropylene, 6-(methyl formate)pyridine-3-boric acid, dichloro(1,5-cyclooctadiene)rhodium, and N,N-dimethylformamide were reacted at 80° C. under the condition of carbon monoxide flow for 18-20 hours. After the reaction was completed, the modified polypropylene was obtained by vacuum rotary evaporation; (4) Pretreated calcium carbonate, 3-thiophene carboxaldehyde, and acetone were mixed in a mass ratio of 1:(2-3):(20-30), ultrasonically dispersed uniformly, heated to 30-40°C for reaction for 6-8h, filtered after the reaction, washed with pure water 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-(thiophen-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 minutes, add 40%-50% thiophene solution and stir for 1-2 hours, add 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution and stir for 1-2 hours, then add the remaining thiophene solution and stir for 1-2 hours, then add 6-(3-thiophene)pyridine-2-carboxaldehyde solution and stir for 3-4 hours. After stirring, filter and wash with pure water 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. The melting temperature is 190-200°C. After extrusion, the materials are sent to a pelletizer for granulation to obtain recycled polypropylene for preparing aging-resistant material.

3. The method for preparing high-impact materials 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 materials 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 materials 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, reflux reaction is carried out for 3-4 hours, filtering and washing with anhydrous ethanol 4 times, and vacuum drying to obtain pretreated calcium carbonate.

6. The method for preparing high-impact materials 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-(thiophen-2-yl)pyridine-2-carboxylic acid solution is obtained by mixing 6-(thiophen-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 materials by recycling polypropylene according to claim 2, characterized in that: The weighing amounts of the components in step (5) are: 1 part of pre-modified calcium carbonate, 0.5 part of thiophene solution, 0.1-0.2 part of 6-(thiophen-2-yl)pyridine-2-carboxylic acid solution, 0.1-0.3 part 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 materials 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 materials by recycling polypropylene according to claim 4, characterized in that: The calcium carbonate specification is 1250 mesh.