Method for recycling plastics using degradable materials

Abstract

The application discloses a method for recycling plastic by using degradable materials. The method comprises the following steps: (1) washing and drying the degradable materials, crushing them, and placing them in a flotation device to screen out the degradable material particles through flotation; (2) dissolving polyacrylamide polymers in distilled water to obtain a modified solution, drying the obtained degradable material particles, placing them in the modified solution, stirring, ultrasonic treatment, taking out the modified degradable material particles, drying, mixing, and heating and melting to obtain a liquid mixture; (3) adding polyurethane urea elastic materials to the liquid mixture to obtain recycled plastic. The method can obtain recycled plastic from degradable materials, improve resource utilization, improve adhesion after modification by polyacrylamide polymers, and improve the mechanical properties and toughness of the recycled plastic by adding polyurethane urea elastic materials to the molten liquid mixture.

Description

Technical Field

[0001] This invention belongs to the field of recycled plastics technology, specifically relating to a method for recycling plastics using biodegradable materials. Background Technology

[0002] Recycled plastics refer to plastic raw materials obtained by processing waste plastics through physical or chemical methods such as pretreatment, melt granulation, and modification. This represents the reuse of plastics. By recycling biodegradable materials, waste resources can be effectively utilized, reducing the demand for virgin materials and achieving resource recycling. Compared to traditional plastic production processes, the recycling process of biodegradable materials reduces energy consumption and greenhouse gas emissions, helping to mitigate climate change. Furthermore, biodegradable materials can decompose into harmless substances under appropriate conditions, reducing pollution and harm to the environment.

[0003] Patent CN 116535705 A discloses a method for preparing fully biodegradable films using biodegradable plastics and biomass materials. The method includes the following steps: adding starch, a starch modifier, and xylene to a nitrogen-protected three-necked flask and stirring; raising the temperature of the three-necked flask to 60-80°C and reacting for 2-4 hours; and then processing to obtain modified starch. PBS, PBAT, modified starch, modified silica, and additives are then mixed evenly and added to a screw extruder for melt extrusion and granulation to obtain composite resin particles. The fully biodegradable film prepared by this invention not only has good mechanical properties but also good biodegradability, making it very environmentally friendly. However, there is still room for improvement in the adhesive properties of the composite resin particles obtained by this method, as well as the mechanical properties and toughness of the fully biodegradable film. Summary of the Invention

[0004] The purpose of this invention is to provide a method for recycling recycled plastics using biodegradable materials, which solves the technical problems of poor adhesive properties, mechanical properties and toughness of recycled plastics in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a method for recycling plastics using biodegradable materials, comprising the following steps:

[0007] Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation.

[0008] In the above process, a flotation device is used to screen biodegradable materials. Flotation can separate target particles from other impurity particles based on the buoyancy differences of biodegradable materials, thereby improving the purity and efficiency of the recovery. The flotation device can be adjusted according to the characteristics and requirements of biodegradable materials to meet the screening needs of different particle sizes, densities and buoyancy. Moreover, the operation of the flotation device is relatively simple and energy-efficient, which helps to reduce production costs and environmental impact.

[0009] Step (2) Dissolve polyacrylamide polymers in distilled water to obtain a modified solution. After drying the obtained biodegradable material particles, place them in the modified solution, stir, sonicate, remove the modified biodegradable material particles, dry, mix, heat and melt to obtain a liquid mixture.

[0010] In the above process, by modifying the biodegradable material particles with polyacrylamide polymers, the polyacrylamide polymers can physically interact with the biodegradable material particles, which can increase the adhesion between the materials and improve the adhesion performance. Polyacrylamide polymers have cross-linking properties, which can firmly bond the biodegradable material particles together at the molecular level, increase adhesion, improve the processing performance of the biodegradable material particles, and make them easier to mold and process.

[0011] Step (3) Add polyurethane urea elastic material to the liquid mixture to obtain recycled plastic.

[0012] In the above process, the synthesized polyurethane urea elastomer is added to the molten biodegradable material, existing in the form of tiny particles or fibers. This effectively fills and enhances the volume of the biodegradable material, improving its density and strength. The molecular structure of the polyurethane urea elastomer contains cross-linked structures and elastic segments, which can interact with the molecular chains of the biodegradable material, enhancing the inter-chain bonding force and improving the material's mechanical properties and toughness. The polyurethane urea elastomer also has excellent energy absorption and dispersion capabilities. When subjected to external forces, it absorbs and disperses energy, reducing stress concentration in the biodegradable material and improving its impact resistance and toughness. Simultaneously, the polyurethane urea elastomer itself possesses excellent elasticity and flexibility; its addition further enhances the elasticity and flexibility of the biodegradable material, making it more resistant to tension and bending.

[0013] Preferably, the biodegradable material is derived from waste materials generated during petrochemical industrial processing, and its main components are polylactic acid and polyethylene, with polylactic acid accounting for 60-80 parts by weight and polyethylene accounting for 40-45 parts by weight.

[0014] Preferably, in step (2), the method for preparing the polyacrylamide polymer includes the following steps:

[0015] P1: Add acrylamide, ethyl acrylate and acrylic acid to a three-necked round-bottom flask, then add potassium persulfate and sodium bisulfite, and stir until completely dissolved;

[0016] P2: Under nitrogen protection, the reaction temperature and reaction time are controlled. After the reaction is completed, a solid gel-like substance is obtained. The obtained solid gel-like substance is soaked in ethanol. After soaking, the product is rinsed with deionized water, dried, and ground to obtain a polyacrylamide polymer.

[0017] The reaction equations for the polyacrylamide polymers in the above process are shown below:

[0018]

[0019] Preferably, in step P1, the purity of acrylamide is 98%, the purity of ethyl acrylate is 98%, the purity of acrylic acid is 98%, and the molar ratio of acrylamide, ethyl acrylate, and acrylic acid is 1:(2-4):(2-5); the purity of potassium persulfate is 99%, the purity of sodium bisulfite is 99%, and the stirring time is 30-50 min; in step P2, the reaction temperature is 50-60℃, the reaction time is 24-30 h, the soaking time is 12-15 h, the number of rinsings is 3-5 times, the drying temperature is 60-70℃, and the product is dried until the weight is constant.

[0020] Preferably, in step (2), the mass ratio of polyacrylamide polymer to biodegradable material particles is 1:(80-90), the stirring time is 30-50 min, the ultrasonic treatment time is 20-40 min, the drying temperature is 70-80℃, the drying time is 1-2 h, and the heating temperature is 180-200℃.

[0021] Preferably, the method for preparing the polyurethane urea elastic material includes the following steps:

[0022] S1: Place polycaprolactone diol in a dry three-necked flask, heat until melted, and remove moisture and oxygen by vacuuming; add isophorone diisocyanate and dibutyltin dilaurate to the three-necked flask, and stir continuously under heating conditions and nitrogen protection to obtain isocyanate-terminated prepolymer.

[0023] S2: Cool the three-necked flask, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, continue to add dihydrazine p-benzoate to the three-necked flask, react at room temperature to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat, and vacuum dry to obtain a polyurethane urea elastomer material.

[0024] The synthesis process of polyurethane urea elastic material is as follows:

[0025]

[0026] Preferably, in step S1, the three-necked flask is connected to a nitrogen line, a reflux condenser, and a mechanical stirrer.

[0027] Preferably, in step S1, the relative molecular mass of polycaprolactone diol is 2000 Da, the heating temperature is 80-85℃, the molar ratio of polycaprolactone diol, isophorone diisocyanate and dibutyltin dilaurate is 1:(1.8-2.2):(0.011-0.015), the heating temperature is 80-90℃, and the stirring time is 3-4 hours.

[0028] Preferably, in step S2, the cooling temperature is 25-28℃, the molar ratio of dihydrazine p-benzoate to polycaprolactone diol is 1:(0.8-1.2), the reaction time is 24-30h, the heating temperature is 50-60℃, the heating time is 10-14h, the vacuum drying temperature is 80-90℃, and the vacuum drying time is 12-16h.

[0029] Preferably, in step (3), the mass ratio of polyurethane urea elastic material to biodegradable material is 1:(100-140).

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] 1. This invention first selects target particles through flotation screening, then modifies the target particles using polyacrylamide polymers to improve their adhesion properties, and adds polyurethane urea elastic material to the molten modified target particles to improve the mechanical properties and toughness of the recycled plastic. By recycling biodegradable materials, the utilization rate of resources is improved, and the recycling of resources is realized.

[0032] 2. This invention obtains target biodegradable material particles by using a simple flotation device. This device effectively separates target particles from impurity particles based on the buoyancy differences of biodegradable materials, improving the purity and efficiency of the recovery. In addition, the flotation device can be adjusted according to the characteristics and requirements of biodegradable materials to meet the screening requirements of different particle sizes, densities and buoyancy. At the same time, the flotation device is simple to operate and has low energy consumption, which helps to reduce production costs and reduce environmental impact.

[0033] 3. This invention uses polyacrylamide polymers to modify the target particles to enhance their adhesive properties. Polyacrylamide polymers can physically interact with degradable materials, thereby improving the adhesion between materials. In addition, polyacrylamide polymers have cross-linking properties, which help to firmly bond degradable material particles together at the molecular level, giving the degradable material particles good adhesive properties.

[0034] 4. This invention adds polyurethane urea elastic material to molten biodegradable material. The polyurethane urea elastic material exists in the form of microparticles or fibers, which can effectively fill and enhance the volume of the biodegradable material, thereby improving the material's density and strength. In addition, the molecular structure of polyurethane urea elastic material contains cross-linked structures and elastic segments, which can enhance the bonding force between the molecular chains of the biodegradable material, giving it excellent mechanical properties and toughness. At the same time, polyurethane urea elastic material itself has excellent elasticity and flexibility, and its addition can increase the elasticity and flexibility of the biodegradable material, giving it good tensile and bending resistance. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the flotation device of the present invention.

[0037] Attached reference numerals: 1. Overflow port; 2. Stirring rod; 3. Upper collection point; 4. Flotation column; 5. Biodegradable material particles; 6. Air inlet; 7. Bottom plate; 8. Sand core; 9. Adjustable air pump. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] This embodiment discloses a flotation device, the structure of which is as follows: Figure 1As shown in the diagram, the flotation device includes an upper collection point 3, a flotation column 4, and a bottom plate 7 arranged sequentially from top to bottom. Biodegradable material particles 5 are placed inside the cavities of the upper collection point 3 and the flotation column 4. A stirring rod 2 is inserted into the cavities of the upper collection point 3 and the flotation column 4. An overflow port 1 extends from the side wall of the upper collection point 3. The bottom of the flotation column 4 is filled with a sand core 8. An air inlet 6 extends from the side wall of the bottom of the flotation column 4 near the sand core 8 and is connected to an adjustable air pump 9. An ultra-quiet adjustable air pump is used to aerate the flotation column. During flotation, the ultra-quiet adjustable air pump blows air at the bottom of the flotation column. Compressed air passes through the sand core at the bottom of the flotation column, generating a large number of tiny bubbles. During flotation, these bubbles are adsorbed onto the biodegradable material particles 5. Depending on the surface properties of different particles, different numbers of bubbles are adsorbed. The bubbles generated inside the flotation column create minor turbulence. Stirring with a glass rod enhances the turbulence inside the flotation column, optimizing the flotation process. The biodegradable material particles that float to the top overflow at the top of the flotation column and enter the upper collection point. After flotation, the biodegradable material particles collected at the upper collection point are taken out as the target particles.

[0041] Example 2

[0042] This embodiment discloses a method for preparing polyacrylamide polymers, including the following steps:

[0043] P1: Add 71g of 98% acrylamide, 300g of 98% ethyl acrylate and 288g of 98% acrylic acid to a three-necked round-bottom flask, then add 99% potassium persulfate and 99% sodium bisulfite, stir for 40 minutes to dissolve completely.

[0044] P2: Under nitrogen protection, the reaction temperature was controlled at 55℃ and the reaction time was 24h. After the reaction, a solid gel-like substance was obtained. The obtained solid gel-like substance was soaked in ethanol for 14h. After soaking, the product was washed 5 times with deionized water, dried at 70℃ until the product weight was constant, and ground to obtain a polyacrylamide polymer.

[0045] This embodiment discloses a method for preparing a polyurethane urea elastic material, including the following steps:

[0046] S1: 12.00 g of polycaprolactone diol with a relative molecular mass of 2000 Da was placed in a dry three-necked flask connected to a nitrogen line, a reflux condenser, and a mechanical stirrer. The mixture was heated to 80 °C until melted, and the reaction system was evacuated to remove moisture and oxygen. 2.67 g of isophorone diisocyanate and 50.00 mg of dibutyltin dilaurate were added to the three-necked flask. The mixture was stirred continuously for 3 h at 80 °C under nitrogen protection to obtain an isocyanate-terminated prepolymer.

[0047] S2: Cool the three-necked flask to 25°C, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, add 1.16g of dihydrazine p-benzoate to the three-necked flask, react at room temperature for 24h to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat at 50°C for 12h, and vacuum dry at 80°C for 12h to obtain a polyurethane urea elastomer material.

[0048] This embodiment discloses a method for recycling plastics using biodegradable materials, including the following steps:

[0049] Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation. The biodegradable material comes from waste materials generated during the petrochemical industry processing. Its main components are polylactic acid and polyethylene. The weight of polylactic acid is 60-80 parts by weight and the weight of polyethylene is 40-45 parts by weight.

[0050] Step (2) Dissolve 2g of polyacrylamide polymer in distilled water to obtain a modified solution. After drying 170g of the obtained biodegradable material particles, place them in the modified solution, stir for 40min, sonicate for 30min, take out the modified biodegradable material particles, dry at 80℃ for 1h, mix, heat to 200℃ to melt, and obtain a liquid mixture.

[0051] Step (3) Add 1g of polyurethane urea elastic material to 120g of liquid mixture to obtain recycled plastic.

[0052] Example 3

[0053] This embodiment discloses a method for preparing polyacrylamide polymers, including the following steps:

[0054] P1: Add 70g of 98% acrylamide, 298g of 98% ethyl acrylate and 286g of 98% acrylic acid to a three-necked round-bottom flask, then add 99% potassium persulfate and 99% sodium bisulfite, stir for 40 minutes to dissolve completely.

[0055] P2: Under nitrogen protection, the reaction temperature was controlled at 55℃ and the reaction time was 24h. After the reaction, a solid gel-like substance was obtained. The obtained solid gel-like substance was soaked in ethanol for 14h. After soaking, the product was washed 5 times with deionized water, dried at 70℃ until the product weight was constant, and ground to obtain a polyacrylamide polymer.

[0056] This embodiment discloses a method for preparing a polyurethane urea elastic material, including the following steps:

[0057] S1: 12.05 g of polycaprolactone diol with a relative molecular mass of 2000 Da was placed in a dry three-necked flask connected to a nitrogen line, a reflux condenser, and a mechanical stirrer. The mixture was heated to 80 °C until melted, and the reaction system was evacuated to remove moisture and oxygen. 2.63 g of isophorone diisocyanate and 50.05 mg of dibutyltin dilaurate were added to the three-necked flask. The mixture was stirred continuously for 3 h at 80 °C under nitrogen protection to obtain an isocyanate-terminated prepolymer.

[0058] S2: Cool the three-necked flask to 25°C, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, add 1.18g of dihydrazine p-benzoate to the three-necked flask, react at room temperature for 24h to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat at 50°C for 12h, and vacuum dry at 80°C for 12h to obtain a polyurethane urea elastomer material.

[0059] This embodiment discloses a method for recycling plastics using biodegradable materials, including the following steps:

[0060] Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation. The biodegradable material comes from waste materials generated during the petrochemical industry processing. Its main components are polylactic acid and polyethylene. The weight of polylactic acid is 60-80 parts by weight and the weight of polyethylene is 40-45 parts by weight.

[0061] Step (2) Dissolve 2g of polyacrylamide polymer in distilled water to obtain a modified solution. Dry 180g of the obtained biodegradable material particles and place them in the modified solution. Stir for 40min, sonicate for 30min, take out the modified biodegradable material particles, dry at 80℃ for 1h, mix, heat to 200℃ to melt, and obtain a liquid mixture.

[0062] Step (3) Add 1g of polyurethane urea elastic material to 140g of liquid mixture to obtain recycled plastic.

[0063] Example 4

[0064] This embodiment discloses a method for preparing polyacrylamide polymers, including the following steps:

[0065] P1: Add 72g of 98% acrylamide, 301g of 98% ethyl acrylate and 290g of 98% acrylic acid to a three-necked round-bottom flask, then add 99% potassium persulfate and 99% sodium bisulfite, and stir for 40 minutes to dissolve completely.

[0066] P2: Under nitrogen protection, the reaction temperature was controlled at 55℃ and the reaction time was 24h. After the reaction, a solid gel-like substance was obtained. The obtained solid gel-like substance was soaked in ethanol for 14h. After soaking, the product was washed 5 times with deionized water, dried at 70℃ until the product weight was constant, and ground to obtain a polyacrylamide polymer.

[0067] This embodiment discloses a method for preparing a polyurethane urea elastic material, including the following steps:

[0068] S1: 11.95 g of polycaprolactone diol with a relative molecular mass of 2000 Da was placed in a dry three-necked flask connected to a nitrogen line, a reflux condenser, and a mechanical stirrer. The mixture was heated to 80 °C until melted, and the reaction system was evacuated to remove moisture and oxygen. 2.69 g of isophorone diisocyanate and 50.10 mg of dibutyltin dilaurate were added to the three-necked flask. The mixture was stirred continuously for 3 h at 80 °C under nitrogen protection to obtain an isocyanate-terminated prepolymer.

[0069] S2: Cool the three-necked flask to 25°C, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, add 1.15g of dihydrazine p-benzoate to the three-necked flask, react at room temperature for 24h to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat at 50°C for 12h, and vacuum dry at 80°C for 12h to obtain a polyurethane urea elastomer material.

[0070] This embodiment discloses a method for recycling plastics using biodegradable materials, including the following steps:

[0071] Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation. The biodegradable material comes from waste materials generated during the petrochemical industry processing. Its main components are polylactic acid and polyethylene. The weight of polylactic acid is 60-80 parts by weight and the weight of polyethylene is 40-45 parts by weight.

[0072] Step (2) Dissolve 2g of polyacrylamide polymer in distilled water to obtain a modified solution. After drying 160g of the obtained biodegradable material particles, place them in the modified solution, stir for 40min, sonicate for 30min, take out the modified biodegradable material particles, dry at 80℃ for 1h, mix, heat to 200℃ to melt, and obtain a liquid mixture.

[0073] Step (3) Add 1g of polyurethane urea elastic material to 100g of liquid mixture to obtain recycled plastic.

[0074] Example 5

[0075] This embodiment discloses a method for preparing polyacrylamide polymers, including the following steps:

[0076] P1: Add 71g of 98% acrylamide, 299g of 98% ethyl acrylate and 289g of 98% acrylic acid to a three-necked round-bottom flask, then add 99% potassium persulfate and 99% sodium bisulfite, stir for 40 minutes to dissolve completely.

[0077] P2: Under nitrogen protection, the reaction temperature was controlled at 55℃ and the reaction time was 24h. After the reaction, a solid gel-like substance was obtained. The obtained solid gel-like substance was soaked in ethanol for 14h. After soaking, the product was washed 5 times with deionized water, dried at 70℃ until the product weight was constant, and ground to obtain a polyacrylamide polymer.

[0078] This embodiment discloses a method for preparing a polyurethane urea elastic material, including the following steps:

[0079] S1: 11.90 g of polycaprolactone diol with a relative molecular mass of 2000 Da was placed in a dry three-necked flask connected to a nitrogen line, a reflux condenser, and a mechanical stirrer. The mixture was heated to 80 °C until melted, and the reaction system was evacuated to remove moisture and oxygen. 2.71 g of isophorone diisocyanate and 49.90 mg of dibutyltin dilaurate were added to the three-necked flask. The mixture was stirred continuously for 3 h at 80 °C under nitrogen protection to obtain an isocyanate-terminated prepolymer.

[0080] S2: Cool the three-necked flask to 25°C, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, add 1.11g of dihydrazine p-benzoate to the three-necked flask, react at room temperature for 24h to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat at 50°C for 12h, and vacuum dry at 80°C for 12h to obtain a polyurethane urea elastomer material.

[0081] This embodiment discloses a method for recycling plastics using biodegradable materials, including the following steps:

[0082] Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation. The biodegradable material comes from waste materials generated during the petrochemical industry processing. Its main components are polylactic acid and polyethylene. The weight of polylactic acid is 60-80 parts by weight and the weight of polyethylene is 40-45 parts by weight.

[0083] Step (2) Dissolve 2g of polyacrylamide polymer in distilled water to obtain a modified solution. After drying 175g of the obtained biodegradable material particles, place them in the modified solution, stir for 40min, sonicate for 30min, take out the modified biodegradable material particles, dry at 80℃ for 1h, mix, heat to 200℃ to melt, and obtain a liquid mixture.

[0084] Step (3) Add 1g of polyurethane urea elastic material to 130g of liquid mixture to obtain recycled plastic.

[0085] Comparative Example 1

[0086] Compared with Example 2, Comparative Example 1 did not use a flotation device for screening, but directly modified polyacrylamide polymers, while other conditions remained unchanged.

[0087] Comparative Example 2

[0088] Compared with Example 2, Comparative Example 2 did not use polyacrylamide polymer modification, and all other conditions remained unchanged.

[0089] Comparative Example 3

[0090] Compared with Example 2, Comparative Example 3 did not add polyurethane urea elastic material, and all other conditions remained the same.

[0091] Experimental Example

[0092] The performance of recycled plastics obtained from Examples 2-5 and Comparative Examples 1-3 using biodegradable materials was tested.

[0093] I. Mechanical Properties

[0094] The test results for the tensile properties of plastics according to the test method specified in GB / T 1040 are shown in Table 1.

[0095] Table 1

[0096]

[0097] As shown in Table 1, the recycled plastics prepared in Examples 2-5 of this invention possess excellent mechanical properties. A comparison between Comparative Example 1 and Examples 2-5 shows that using a flotation device can increase the mechanical properties of the recycled plastics; a comparison between Comparative Example 2 and Examples 2-5 shows that modification with polyacrylamide polymers can increase the mechanical properties of the recycled plastics; and a comparison between Comparative Example 3 and Examples 2-5 shows that adding polyurethane urea elastic material can increase the mechanical properties of the recycled plastics.

[0098] II. Resilience

[0099] The test results for the impact toughness of plastics, as specified in GB / T 1043, are shown in Table 2.

[0100] Table 2

[0101]

[0102] As shown in Table 2, the recycled plastics prepared in Examples 2-5 of this invention exhibit excellent toughness. A comparison between Comparative Example 1 and Examples 2-5 shows that using a flotation device can increase the toughness of the recycled plastics; a comparison between Comparative Example 2 and Examples 2-5 shows that modification with polyacrylamide polymers can increase the toughness of the recycled plastics; and a comparison between Comparative Example 3 and Examples 2-5 shows that adding polyurethane urea elastic material can increase the toughness of the recycled plastics.

[0103] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0104] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for recycling and regenerating plastics using biodegradable materials, characterized in that, Includes the following steps: Step (1) After cleaning and drying the biodegradable material, crush it and place it in a flotation device to screen out the biodegradable material particles by flotation. Step (2) Dissolve polyacrylamide polymers in distilled water to obtain a modified solution. Dry the obtained biodegradable material particles and place them in the modified solution. Stir, sonicate, remove the modified biodegradable material particles, dry, mix, heat and melt to obtain a liquid mixture. Step (3) Add polyurethane urea elastic material to the liquid mixture to obtain recycled plastic; The biodegradable material is derived from waste generated during the petrochemical industry. Its main components are polylactic acid and polyethylene, with polylactic acid accounting for 60-80 parts by weight and polyethylene accounting for 40-45 parts by weight. The preparation method of the polyacrylamide polymer includes the following steps: P1: Add acrylamide, ethyl acrylate and acrylic acid to a three-necked round-bottom flask, then add potassium persulfate and sodium bisulfite, and stir until completely dissolved; P2: Under nitrogen protection, the reaction temperature and reaction time are controlled. After the reaction is completed, a solid gel-like substance is obtained. The obtained solid gel-like substance is soaked in ethanol. After soaking, the product is rinsed with deionized water, dried, and ground to obtain a polyacrylamide polymer. In step P1, the molar ratio of acrylamide, ethyl acrylate, and acrylic acid is 1:(2-4):(2-5); in step P2, the reaction temperature is 50-60℃ and the reaction time is 24-30h. In step (2), the mass ratio of polyacrylamide polymer to biodegradable material particles is 1:(80-90).

2. The method for recycling and regenerating plastics using biodegradable materials according to claim 1, characterized in that, In step P1, the purity of acrylamide is 98%, the purity of ethyl acrylate is 98%, the purity of acrylic acid is 98%, the purity of potassium persulfate is 99%, and the purity of sodium bisulfite is 99%, and the stirring time is 30-50 min; in step P2, the soaking time is 12-15 h, the rinsing number is 3-5 times, the drying temperature is 60-70℃, and the product is dried until the weight is constant.

3. The method for recycling and regenerating plastics using biodegradable materials according to claim 1, characterized in that, In step (2), the stirring time is 30-50 min, the ultrasonic treatment time is 20-40 min, the drying temperature is 70-80℃, the drying time is 1-2 h, and the heating temperature is 180-200℃.

4. The method for recycling and regenerating plastics using biodegradable materials according to claim 1, characterized in that, The preparation method of the polyurethane urea elastic material includes the following steps: S1: Place polycaprolactone diol in a dry three-necked flask, heat until melted, and remove moisture and oxygen by vacuuming; add isophorone diisocyanate and dibutyltin dilaurate to the three-necked flask, and stir continuously under heating conditions and nitrogen protection to obtain isocyanate-terminated prepolymer. S2: Cool the three-necked flask, add dry N,N-dimethylformamide to it, dissolve to obtain a transparent solution, continue to add dihydrazine p-benzoate to the three-necked flask, react at room temperature to obtain a polyurethane urea elastomer solution, place the obtained solution on a glass substrate, heat, and vacuum dry to obtain a polyurethane urea elastomer material.

5. The method for recycling and regenerating plastics using biodegradable materials according to claim 4, characterized in that, In step S1, the three-necked flask is connected to a nitrogen line, a reflux condenser, and a mechanical stirrer.

6. The method for recycling and regenerating plastics using biodegradable materials according to claim 4, characterized in that, In step S1, the relative molecular mass of polycaprolactone diol is 2000, the heating temperature is 80-85℃, the molar ratio of polycaprolactone diol, isophorone diisocyanate and dibutyltin dilaurate is 1:(1.8-2.2):(0.011-0.015), the heating temperature is 80-90℃, and the stirring time is 3-4h.

7. The method for recycling and regenerating plastics using biodegradable materials according to claim 4, characterized in that, In step S2, the cooling temperature is 25-28℃, the molar ratio of dihydrazine p-benzoate to polycaprolactone diol is 1:(0.8-1.2), the reaction time is 24-30h, the heating temperature is 50-60℃, the heating time is 10-14h, the vacuum drying temperature is 80-90℃, and the vacuum drying time is 12-16h.

8. The method for recycling and regenerating plastics using biodegradable materials according to claim 1, characterized in that, In step (3), the mass ratio of polyurethane urea elastic material to biodegradable material is 1:(100-140).

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