Modified plastic particle with impact resistance and preparation method thereof

Abstract

The invention provides modified plastic particles with impact resistance and a preparation method thereof, and the modified plastic particles comprise the following components by weight: 82%-88% of polypropylene, 8%-12% of a polyolefin elastomer-maleic anhydride copolymer and 4%-6% of a functional composite modified material. Maleic anhydride is grafted to the polyolefin elastomer to form the polyolefin elastomer-maleic anhydride copolymer, and the polyolefin elastomer-maleic anhydride copolymer is applied to polypropylene, so that the acting force between the polypropylene and the polyolefin elastomer is effectively improved, and the impact strength and the elongation at break of modified plastic particles are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic particles, and in particular to modified plastic particles with impact resistance and a preparation method thereof. Background Art

[0002] PP plastic has a very low density and is one of the lightest types of plastic. PP plastic has good comprehensive properties such as chemical resistance, heat resistance, electrical insulation, high wear resistance, high strength mechanical properties and mechanical properties. PP plastic products have excellent resistance to bending fatigue and can withstand multiple folding and bending without damage. PP plastic has high application value in the manufacture of durable consumer goods and packaging materials, and is suitable for food packaging and medical devices.

[0003] However, PP plastic products have low brittle toughness and impact strength. PP materials are prone to cracking or even breaking after being subjected to high-pressure impact, blows or collisions. For plastic products that require high impact or collision resistance, pure PP plastic is difficult to meet the use requirements.

[0004] POE is a thermoplastic elastomer with excellent thermal stability, optical properties, and crack resistance. POE-modified copolymers can ensure product integrity in high-impact applications. Conventional POE-modified PP plastic particles rely solely on physical blending. While this approach offers simplicity and low production costs, the resulting plastic particles often suffer from low impact strength and elongation at break. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a modified plastic particle with impact resistance and a preparation method thereof.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: The present application discloses a modified plastic particle with impact resistance. The components of the modified plastic particle are as follows, calculated by weight percentage: 82%-88% polypropylene, 8%-12% polyolefin elastomer-maleic anhydride copolymer, and 4%-6% functional composite modified material.

[0007] By setting up the above technical scheme, maleic anhydride is grafted onto polyolefin elastomer to form a polyolefin elastomer-maleic anhydride copolymer, which is applied to polypropylene, effectively improving the interaction force between polypropylene and polyolefin elastomer, and improving the impact strength and elongation at break of the modified plastic particles.

[0008] Preferably, in terms of weight percentage, the components of the polyolefin elastomer-maleic anhydride copolymer are as follows: 96% polyolefin elastomer, 4% maleic anhydride; the components of the functional composite modified material are as follows: 5%-10% filler, 30%-40% solvent, 15%-25% initiator, 10%-14% isosorbide, and 20%-30% styrene.

[0009] By setting up the above technical scheme, isosorbide can be dissolved in the PP melt and preferentially precipitated to form a nanofiber structure before the PP begins to crystallize, inducing PP nucleation crystallization and increasing the PP crystallization rate. The nanofiber structure formed by isosorbide enhances the structural strength of PP, which is beneficial to improving the structural strength and impact resistance of the modified plastic particle product.

[0010] Preferably, the solvent consists of xylene and epoxidized soybean oil in a mass ratio of 1:1.

[0011] By setting up the above technical solution, xylene and polyolefin elastomer have similar solubility parameters, and epoxidized soybean oil contains a large number of groups that can react with maleic anhydride. The synergistic effect of xylene and epoxidized soybean oil can improve the dispersion uniformity of maleic anhydride in the polyolefin elastomer molecules, thereby fully improving the grafting rate and efficiency of maleic anhydride and polyolefin elastomer.

[0012] Preferably, the initiator is one of diisopropyl peroxide or benzoyl peroxide.

[0013] Preferably, the filler is modified wollastonite, and its preparation steps are as follows: wollastonite powder, acetone and water are weighed in a mass ratio of 7:2:5, 2% by mass fraction of KH-560 is added dropwise under mechanical stirring conditions, and 0.2 mol of HCl is used to adjust the pH to 5.5, and the mixture is reacted at 85°C for 2h, followed by filtration, washing and drying to obtain the modified wollastonite.

[0014] By setting up the above technical scheme, the surface polarity of wollastonite treated with the coupling agent is reduced, the active sites of wollastonite are increased, and the wollastonite can be evenly dispersed in the copolymer of polypropylene, polyolefin elastomer and maleic anhydride. Part of the maleic anhydride combines with the modified wollastonite to form hydrogen bonds, thereby enhancing the interfacial effect between molecules, which is beneficial to improving the structural strength and impact resistance of the modified plastic ions.

[0015] Preferably, the preparation steps of the polyolefin elastomer-maleic anhydride copolymer are as follows: weighing a polyolefin elastomer and maleic anhydride in proportion, dissolving the maleic anhydride in acetone, dispersing the polyolefin elastomer and the dissolved maleic anhydride solution in a high-speed disperser for 2 minutes, and after the acetone is completely volatilized, adding the mixture to a screw extruder for extrusion and granulation to obtain the polyolefin elastomer-maleic anhydride copolymer.

[0016] Preferably, during the preparation of the polyolefin elastomer-maleic anhydride copolymer, the solvent is weighed in proportion and dispersed together with the polyolefin elastomer and maleic anhydride at a high speed.

[0017] Preferably, the extrusion conditions of the screw extruder are: screw speed: 150-300 rpm, screw temperature: 225-245° C., die head melt pressure: 50 bar, reaction residence time: 150-200 s.

[0018] Preferably, the polypropylene is pretreated, and the specific steps are as follows: weigh the polypropylene and place it in the sample chamber of a pressure-volume-temperature measuring instrument, heat it until the polypropylene melts, completely remove the bubbles, treat it with pressures of 20 MPa, 60 MPa, 100 MPa, and 140 MPa in sequence, perform non-isothermal crystallization at a cooling rate of 2 K / min, cool it to room temperature, and select isotactic polypropylene using wide-angle X-ray diffraction and small-angle X-ray scattering experiments.

[0019] The present application also discloses a method for preparing modified plastic particles with impact resistance. The preparation method comprises the following steps: weighing a polyolefin elastomer-maleic anhydride copolymer, isotactic polypropylene and a functional composite modified material in proportion, mixing them evenly, adding them to a twin-screw extruder, extruding and granulating them, and obtaining modified plastic particles with impact resistance.

[0020] Among them, the extrusion conditions of the twin-screw extruder are: Screw speed: 150~300rpm, screw temperature: 225~245℃, die melt pressure: 50bar, reaction residence time: 150~200s.

[0021] By implementing the above technical solution, polypropylene is melted and then subjected to high-pressure treatment to form polymorphic polypropylene with α, β, and γ crystal forms. The γ crystal form is isotactic polypropylene, which can be selected using wide-angle X-ray diffraction and small-angle X-ray scattering experiments. The modified wollastonite exhibits good compatibility with the components of the system consisting of isotactic polypropylene and a polyolefin elastomer-maleic anhydride copolymer, resulting in strong interfacial bonding, which enhances the tensile strength and overall mechanical properties of the prepared modified plastic particles. Styrene grafting onto the system consisting of isotactic polypropylene and a polyolefin elastomer-maleic anhydride copolymer reduces the melt flow rate of the isotactic polypropylene and increases its melt strength. High-melt-strength isotactic polypropylene can better maintain shape stability during processing and reduce flow deformation, thereby improving the dimensional accuracy and surface quality of the modified plastic particles.

[0022] The beneficial effects of the present invention are: The invention forms a polyolefin elastomer-maleic anhydride copolymer by grafting maleic anhydride onto a polyolefin elastomer, and applies the copolymer to polypropylene, thereby effectively improving the interaction between the polypropylene and the polyolefin elastomer and increasing the impact strength and elongation at break of the modified plastic particles.

[0023] Xylene and polyolefin elastomers have similar solubility parameters. Epoxidized soybean oil contains a large number of groups that can react with maleic anhydride. The combined effect of xylene and epoxidized soybean oil can improve the dispersion uniformity of maleic anhydride in polyolefin elastomer molecules, thereby fully improving the grafting rate and efficiency of maleic anhydride and polyolefin elastomer.

[0024] The wollastonite treated with coupling agent reduces the surface polarity of wollastonite and increases the active sites of wollastonite, so that it can be evenly dispersed in copolymers of polypropylene, polyolefin elastomer and maleic anhydride. Part of the maleic anhydride combines with the modified wollastonite to form hydrogen bonds, which enhances the interfacial effect between molecules and is beneficial to improving the structural strength and impact resistance of the modified plastic ions. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] Example 1: This example discloses a modified plastic particle with impact resistance. The components of the modified plastic particle are as follows, in weight percentage: 82% polypropylene, 12% polyolefin elastomer-maleic anhydride copolymer, and 6% functional composite modified material.

[0027] In terms of weight percentage, the composition of the polyolefin elastomer-maleic anhydride copolymer is as follows: 96% polyolefin elastomer and 4% maleic anhydride; the composition of the functional composite modified material is as follows: 5% modified wollastonite, 15% xylene, 15% epoxy soybean oil, 25% diisostyrene peroxide, 10% isosorbide, and 30% styrene.

[0028] In this embodiment, the preparation steps of the polyolefin elastomer-maleic anhydride copolymer are as follows: polyolefin elastomer, maleic anhydride and diisophenylpropionyl peroxide are weighed in proportion, the maleic anhydride is dissolved in acetone, the dissolved maleic anhydride solution, the polyolefin elastomer and diisophenylpropionyl peroxide are dispersed in a high-speed disperser for 2 minutes, and after the acetone is completely evaporated, the mixture is added to a screw extruder for extrusion and granulation to obtain the polyolefin elastomer-maleic anhydride copolymer; Among them, the screw speed is 150, the screw temperature is 225°C, the head melt pressure is 50 bar, and the reaction residence time is 150 s.

[0029] It is worth noting that the preparation steps of modified wollastonite are as follows: wollastonite powder, acetone and water are weighed in a mass ratio of 7:2:5, 2% by mass fraction of KH-560 is added dropwise under mechanical stirring conditions, and 0.2 mol of HCl is used to adjust the pH to 5.5. The mixture is reacted at 85°C for 2 hours, and then filtered, washed and dried in sequence to obtain the modified wollastonite.

[0030] It is worth noting that the polypropylene is pretreated, and the specific steps are as follows: after weighing the polypropylene, put it into the sample chamber of the pressure-volume-temperature measuring instrument, heat it until the polypropylene melts, completely remove the bubbles, and treat it with pressures of 20MPa, 60MPa, 100MPa, and 140MPa in sequence, perform non-isothermal crystallization at a cooling rate of 2K / min, and after cooling to room temperature, use wide-angle X-ray diffraction and small-angle X-ray scattering experiments to select isotactic polypropylene.

[0031] This embodiment also discloses a method for preparing modified plastic particles with impact resistance, comprising the following steps: Weighing polyolefin elastomer-maleic anhydride copolymer, isotactic polypropylene and functional composite modified material in proportion, mixing them evenly, adding them into a twin-screw extruder for extrusion and granulation to obtain modified plastic particles with impact resistance; Among them, the extrusion conditions of the twin-screw extruder are: Screw speed: 150 rpm, screw temperature: 225°C, die melt pressure: 50 bar, reaction residence time: 150 s.

[0032] Example 2: This example discloses a modified plastic particle with impact resistance. The components of the modified plastic particle are as follows, in weight percentage: 88% polypropylene, 8% polyolefin elastomer-maleic anhydride copolymer, and 4% functional composite modified material.

[0033] In terms of weight percentage, the composition of the polyolefin elastomer-maleic anhydride copolymer is as follows: 96% polyolefin elastomer, 4% maleic anhydride; the composition of the functional composite modified material is as follows: 10% modified wollastonite, 20% xylene, 20% epoxidized soybean oil, 16% benzoyl peroxide, 14% isosorbide, and 20% styrene.

[0034] In this embodiment, the preparation steps of the polyolefin elastomer-maleic anhydride copolymer are as follows: polyolefin elastomer, maleic anhydride and benzoyl peroxide are weighed in proportion, the maleic anhydride is dissolved in acetone, the dissolved maleic anhydride solution, the polyolefin elastomer and benzoyl peroxide are dispersed in a high-speed disperser for 2 minutes, and after the acetone is completely evaporated, the mixture is added to a screw extruder for extrusion and granulation to obtain the polyolefin elastomer-maleic anhydride copolymer; Among them, the screw speed is 300 rpm, the screw temperature is 245°C, the head melt pressure is 50 bar, and the reaction residence time is 200 s.

[0035] It is worth noting that the preparation steps of modified wollastonite are as follows: wollastonite powder, acetone and water are weighed in a mass ratio of 7:2:5, 2% by mass fraction of KH-560 is added dropwise under mechanical stirring conditions, and 0.2 mol of HCl is used to adjust the pH to 5.5. The mixture is reacted at 85°C for 2 hours, and then filtered, washed and dried in sequence to obtain the modified wollastonite.

[0036] It is worth noting that the polypropylene is pretreated, and the specific steps are as follows: after weighing the polypropylene, put it into the sample chamber of the pressure-volume-temperature measuring instrument, heat it until the polypropylene melts, completely remove the bubbles, and treat it with pressures of 20MPa, 60MPa, 100MPa, and 140MPa in sequence, perform non-isothermal crystallization at a cooling rate of 2K / min, and after cooling to room temperature, use wide-angle X-ray diffraction and small-angle X-ray scattering experiments to select isotactic polypropylene.

[0037] This embodiment also discloses a method for preparing modified plastic particles with impact resistance, comprising the following steps: Weighing polyolefin elastomer-maleic anhydride copolymer, isotactic polypropylene and functional composite modified material in proportion, mixing them evenly, adding them into a twin-screw extruder for extrusion and granulation to obtain modified plastic particles with impact resistance; Among them, the extrusion conditions of the twin-screw extruder are: Screw speed: 300 rpm, screw temperature: 245°C, die melt pressure: 50 bar, reaction residence time: 200 s.

[0038] Example 3: This example discloses a modified plastic particle with impact resistance. The components of the modified plastic particle are as follows, in weight percentage: 88% polypropylene, 8% polyolefin elastomer-maleic anhydride copolymer, and 4% functional composite modified material.

[0039] In terms of weight percentage, the composition of the polyolefin elastomer-maleic anhydride copolymer is as follows: 96% polyolefin elastomer and 4% maleic anhydride; the composition of the functional composite modified material is as follows: 10% modified wollastonite, 20% xylene, 20% epoxidized soybean oil, 15% benzoyl peroxide, 10% isosorbide, and 25% styrene.

[0040] In this embodiment, the preparation steps of the polyolefin elastomer-maleic anhydride copolymer are as follows: polyolefin elastomer, maleic anhydride and benzoyl peroxide are weighed in proportion, the maleic anhydride is dissolved in acetone, the dissolved maleic anhydride solution, the polyolefin elastomer and benzoyl peroxide are dispersed in a high-speed disperser for 2 minutes, and after the acetone is completely evaporated, the mixture is added to a screw extruder for extrusion and granulation to obtain the polyolefin elastomer-maleic anhydride copolymer; Among them, the screw speed is 300 rpm, the screw temperature is 245°C, the head melt pressure is 50 bar, and the reaction residence time is 200 s.

[0041] It is worth noting that the preparation steps of modified wollastonite are as follows: wollastonite powder, acetone and water are weighed in a mass ratio of 7:2:5, 2% by mass fraction of KH-560 is added dropwise under mechanical stirring conditions, and 0.2 mol of HCl is used to adjust the pH to 5.5. The mixture is reacted at 85°C for 2 hours, and then filtered, washed and dried in sequence to obtain the modified wollastonite.

[0042] It is worth noting that the polypropylene is pretreated, and the specific steps are as follows: after weighing the polypropylene, put it into the sample chamber of the pressure-volume-temperature measuring instrument, heat it until the polypropylene melts, completely remove the bubbles, and treat it with pressures of 20MPa, 60MPa, 100MPa, and 140MPa in sequence, perform non-isothermal crystallization at a cooling rate of 2K / min, and after cooling to room temperature, use wide-angle X-ray diffraction and small-angle X-ray scattering experiments to select isotactic polypropylene.

[0043] This embodiment also discloses a method for preparing modified plastic particles with impact resistance, comprising the following steps: Weighing polyolefin elastomer-maleic anhydride copolymer, isotactic polypropylene and functional composite modified material in proportion, mixing them evenly, adding them into a twin-screw extruder for extrusion and granulation to obtain modified plastic particles with impact resistance; Among them, the extrusion conditions of the twin-screw extruder are: Screw speed: 300 rpm, screw temperature: 245°C, die melt pressure: 50 bar, reaction residence time: 200 s.

[0044] Comparative Example 1: A modified plastic particle with impact resistance. The modified plastic particle is different from Example 3 only in that the polyolefin elastomer-maleic anhydride copolymer is replaced by a polyolefin elastomer.

[0045] Comparative Example 2: A modified plastic particle with impact resistance, the modified plastic particle differs from Example 3 only in that no functional composite modifying material is added.

[0046] Comparative Example 3: Modified plastic particles with impact resistance are prepared. The modified plastic particles differ from those in Example 3 only in that the polypropylene is not pretreated and ordinary polypropylene is used instead of isotactic polypropylene in the preparation of the modified plastic particles.

[0047] Comparative Example 4: A modified plastic particle with impact resistance. The modified plastic particle is different from Example 3 only in that xylene and epoxidized soybean oil are not added.

[0048] Comparative Example 5: A modified plastic particle with impact resistance. The modified plastic particle is different from Example 3 only in that the solvent is entirely composed of xylene.

[0049] Comparative Example 6: A modified plastic particle with impact resistance. The modified plastic particle is different from Example 3 only in that the solvent is entirely composed of epoxidized soybean oil.

[0050] Comparative Example 7: A modified plastic particle with impact resistance, wherein the modified plastic particle differs from Example 3 only in that benzoyl peroxide is not added.

[0051] Comparative Example 8: A modified plastic particle with impact resistance. The modified plastic particle is different from Example 3 only in that ordinary wollastonite is used instead of the modified wollastonite.

[0052] Comparative Example 9: A modified plastic particle with impact resistance, wherein the modified plastic particle differs from comparative example 8 only in that wollastonite is not added.

[0053] Mechanical properties test of polypropylene plastic: 1. The modified plastic particles obtained in Examples 1-3 and Comparative Examples 1-9 were used to prepare the specimens required for mechanical property testing, and the specimens were uniformly made into sheets of 100 mm × 100 mm × 1 mm.

[0054] 2. Tensile properties: The tensile properties test was carried out on an INSTRON material mechanics testing machine according to GB / T1040-2006, with a tensile rate of 60 mm / min and a test temperature of room temperature. Five specimens were tested in each group and the average value was taken as the final result. The results are shown in Table 1.

[0055] 3. Bending properties: Bending tests were performed on an INSTRON material mechanics testing machine according to GB / T9341-2008. The test rate was 3 mm / min and the test temperature was room temperature. Five specimens were tested in each group and the average value was taken as the final result. The results are shown in Table 1.

[0056] 4. Impact Performance: Notched impact strength of the samples was tested on an Izod impact tester according to GB / T1842-2008. Specific method: Injection molded specimens were machined into a V-notch on a notch prototyping machine. The arc radius of the notch bottom was 0.25 mm. The specimens were left at room temperature for 24 hours before testing. Five specimens were tested in each group, and the average value was taken as the final result. The results are shown in Table 1.

[0057] Table 1 Performance parameters of modified plastic particles obtained in Examples 1-3 and Comparative Examples 1-9

[0058] From Table 1 we can see that: The tensile strength, flexural strength and impact strength of the modified plastic particles in Examples 1-3 are all greater than the various data of the modified plastic particles in Comparative Examples 1-9. The addition of functional composite modifying materials can cooperate with polypropylene and polyolefin elastomer-maleic anhydride copolymer and respond to improve the tensile strength, flexural strength and impact strength of the modified plastic particles.

[0059] The difference between Examples 1-3 is mainly the slight difference between the specific content of each component and the parameter data of the preparation method, which has little effect on the tensile strength, flexural strength and impact strength of the modified plastic particles.

[0060] Comparing the mechanical properties of the modified plastic particles in Examples 1-9 with those in Example 3 reveals that replacing the polyolefin elastomer-maleic anhydride copolymer with a polyolefin elastomer, replacing isotactic polypropylene with conventional polypropylene without pretreatment, replacing modified wollastonite with conventional wollastonite, and omitting the addition of wollastonite all significantly reduce the tensile strength, flexural strength, and impact strength of the modified plastic particles. Changing the solvent type has minimal effect on the tensile strength, flexural strength, and impact strength of the modified plastic particles.

[0061] In summary: Maleic anhydride is grafted onto polyolefin elastomer to form a polyolefin elastomer-maleic anhydride copolymer, which is applied to polypropylene, effectively improves the interaction between polypropylene and polyolefin elastomer, and improves the impact strength and elongation at break of the modified plastic particles.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A modified plastic particle with impact resistance, characterized in that: Calculated by weight percentage, the modified plastic particles are composed of the following components: 82%-88% polypropylene, 8%-12% polyolefin elastomer-maleic anhydride copolymer, and 4%-6% functional composite modified material.

2. The modified plastic particles with impact resistance according to claim 1, characterized in that: In weight percentage: The composition of the polyolefin elastomer-maleic anhydride copolymer is as follows: polyolefin elastomer 96%, maleic anhydride 4%; The components of the functional composite modified material are as follows: filler 5%-10%, solvent 30%-40%, initiator 15%-25%, isosorbide 10%-14%, and styrene 20%-30%.

3. The modified plastic particles with impact resistance according to claim 2, characterized in that: The solvent consists of xylene and epoxidized soybean oil in a mass ratio of 1:

1.

4. The modified plastic particles with impact resistance according to claim 3, characterized in that: The initiator is one of diisophenylpropane peroxide or benzoyl peroxide.

5. The modified plastic particles with impact resistance according to claim 4, characterized in that: The filler is modified wollastonite, and its preparation steps are as follows: wollastonite powder, acetone and water are weighed in a mass ratio of 7:2:5, 2% by mass of KH-560 is added dropwise under mechanical stirring conditions, and 0.2 mol of HCl is used to adjust the pH to 5.

5. The mixture is reacted at 85° C. for 2 hours, and then filtered, washed and dried in sequence to obtain the modified wollastonite.

6. The modified plastic particles with impact resistance according to claim 4, characterized in that: The polyolefin elastomer-maleic anhydride copolymer is prepared by weighing a polyolefin elastomer and maleic anhydride in proportion, dissolving the maleic anhydride in acetone, dispersing the polyolefin elastomer and the dissolved maleic anhydride solution in a high-speed disperser for 2 minutes, and adding the polyolefin elastomer to a screw extruder for extrusion and granulation after the acetone is completely volatilized to obtain the polyolefin elastomer-maleic anhydride copolymer.

7. The modified plastic particles with impact resistance according to claim 6, characterized in that: During the preparation of the polyolefin elastomer-maleic anhydride copolymer, the solvent is weighed in proportion and dispersed together with the polyolefin elastomer and maleic anhydride at a high speed.

8. The modified plastic particles with impact resistance according to claim 7, characterized in that: The extrusion conditions of the screw extruder are: Screw speed: 150~300rpm, screw temperature: 225~245℃, die melt pressure: 50bar, reaction residence time: 150~200s.

9. The modified plastic particles with impact resistance according to claim 7, characterized in that: Polypropylene is pretreated, the specific steps are as follows: After weighing polypropylene, place it in the sample chamber of a pressure-volume-temperature measuring instrument. After heating until the polypropylene melts, completely remove the bubbles. Then, apply pressure treatment of 20 MPa, 60 MPa, 100 MPa, and 140 MPa in sequence, and perform non-isothermal crystallization at a cooling rate of 2 K / min. After cooling to room temperature, wide-angle X-ray diffraction and small-angle X-ray scattering experiments are used to select isotactic polypropylene.

10. A method for preparing modified plastic particles with impact resistance according to claim 9, characterized in that: The preparation method comprises the following steps: weighing polyolefin elastomer-maleic anhydride copolymer, isotactic polypropylene and functional composite modified material in proportion, mixing them evenly, adding them into a twin-screw extruder, extruding and granulating them, and obtaining modified plastic particles with impact resistance; Among them, the extrusion conditions of the twin-screw extruder are: Screw speed: 150~300rpm, screw temperature: 225~245℃, die melt pressure: 50bar, reaction residence time: 150~200s.

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