Polypropylene high-rate conductive microcellular foaming master batch and preparation method thereof

Abstract

The invention discloses a polypropylene high-rate conductive microcellular foaming master batch and a preparation method thereof, belongs to the technical field of polypropylene materials, and is used for solving the technical problem that the foaming effect and the conductivity of a polypropylene foaming material in the prior art need to be further improved. Polypropylene, maleic anhydride grafted SBS, a nucleating agent, an antioxidant, a lubricant and polyaniline grafted graphene oxide are subjected to mixing, extrusion, wire drawing, grain-sized dicing and drying in an extruder, and the polypropylene high-rate conductive microcellular foaming master batch is obtained; a polypropylene high-rate conductive microcellular foaming material with good tensile property and conductivity can be obtained from the polypropylene high-rate conductive microcellular foaming master batch prepared by the preparation method through a foaming process.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene materials, and in particular to a polypropylene high-rate conductive microporous foaming masterbatch and a preparation method thereof. Background Art

[0002] With technological advancements, polypropylene, a widely used thermoplastic, has become a vital component in industries such as packaging, automotive, electronics, and home appliances. While polypropylene offers excellent molding and processing properties and chemical stability, its inherent electrical insulation properties hinder its performance in applications requiring specific electrical conductivity, limiting its use in electronics, antistatic materials, and other fields. Traditional conductive polypropylene materials often require a high proportion of conductive fillers to achieve good conductivity, but this approach can result in a decrease in the material's mechanical properties, such as tensile strength.

[0003] Chinese patent CN107828134B discloses a method for preparing highly conductive and flame-retardant polypropylene foam beads. The method comprises mixing polypropylene (A), a nucleating agent masterbatch, a conductive masterbatch, flame retardant masterbatch 1, and flame retardant masterbatch 2 to produce conductive and flame-retardant polypropylene microparticles. The conductive and flame-retardant polypropylene microparticles are then charged into a reactor along with a blowing agent, a dispersant, and the like, and processed by a high-temperature pressure relief method to produce foam beads. The conductive masterbatch is then processed with polypropylene (A) and a conductive filler to produce a conductive masterbatch. The flame retardant masterbatch 1 is then processed with polypropylene (A) and a modified inorganic flame retardant to produce a flame retardant masterbatch. The flame retardant masterbatch 2 is then processed with polypropylene (A) and an organic flame retardant to produce a flame retardant masterbatch. In this invention, the conductive filler in the polypropylene material easily agglomerates, forming an uneven conductive network, which can lead to unstable conductivity. During the foaming process, the filler agglomeration can further affect the nucleation process of the foam cells, thereby affecting the foaming effect and the conductive properties of the material. Summary of the Invention

[0004] The purpose of the present invention is to provide a polypropylene high-rate conductive microporous foam masterbatch and a preparation method thereof, so as to solve the technical problem that the foaming effect and conductivity of polypropylene foam materials in the prior art need to be further improved.

[0005] In order to achieve the above object, the present invention provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0006] Step (1) mixing anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal uniformly, heating to react, and after the reaction is completed, filtering, washing, and vacuum drying to obtain modified graphene oxide;

[0007] Step (2) dispersing the modified graphene oxide in an ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 1-3, stirring, reacting, filtering after the reaction, washing with deionized water until neutral, and drying to obtain polyaniline-grafted graphene oxide;

[0008] Step (3) In a nitrogen environment, polypropylene, maleic anhydride grafted SBS, a nucleating agent, an antioxidant, a lubricant and polyaniline grafted graphene oxide are mixed in an extruder, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foaming masterbatch.

[0009] Preferably, the temperature of each zone of the extruder is basically controlled at 180° C., and the length of the masterbatch is 2-4 mm.

[0010] Preferably, the preparation method of amino-modified graphene oxide comprises the following steps:

[0011] The graphene oxide, anhydrous ethanol and γ-aminopropyltriethoxysilane are uniformly mixed, heated to react, and after the reaction is completed, centrifuged, washed and dried to obtain amino-modified graphene oxide;

[0012] Wherein, the mass ratio of graphene oxide, anhydrous ethanol and γ-aminopropyltriethoxysilane is 40:(1000-1800):(10-15);

[0013] The reaction temperature is 65-85°C and the reaction time is 3-5h.

[0014] Preferably, in step (1), the mass ratio of anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal is (2000-2800):(80-100):(40-60).

[0015] Preferably, in step (1), the reaction temperature is 25-35°C and the reaction time is 3-5h.

[0016] Preferably, in step (1), the vacuum drying conditions are: drying in a vacuum drying oven at 60-70°C for 8-10 hours.

[0017] Preferably, in step (2), the mass ratio of modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate is (60-80):(2500-4500):(250-450):(140-220).

[0018] Preferably, in step (2), the reaction temperature is 20-30°C and the reaction time is 15-18h.

[0019] Preferably, in step (2), the mass concentration of the ethanol aqueous solution is 50%.

[0020] Preferably, in step (2), the pH is adjusted using a 1 mol / L hydrochloric acid aqueous solution.

[0021] Preferably, in step (2), the drying conditions are: drying at 50-60°C for 10-12 hours.

[0022] Preferably, in step (3), the mass ratio of polypropylene, maleic anhydride grafted SBS, nucleating agent, antioxidant, lubricant and polyaniline grafted graphene oxide is (70-85):(5-12):(3-8):(0.5-2):(1-3):(2-6).

[0023] Preferably, in step (3), the nucleating agent is one or more of nano-calcium carbonate, nano-montmorillonite and nano-talc.

[0024] Preferably, in step (3), the antioxidant is one of antioxidant 168 and antioxidant 1010.

[0025] Preferably, in step (3), the lubricant is zinc stearate.

[0026] Preferably, in step (3), the density of polypropylene is 0.9 g / cm 3 .

[0027] Preferably, a polypropylene high-rate conductive microporous foam masterbatch is prepared by the preparation method of the polypropylene high-rate conductive microporous foam masterbatch.

[0028] Preferably, a polypropylene high-rate conductive microporous foam material is obtained by foaming the polypropylene high-rate conductive microporous foam masterbatch.

[0029] Preferably, the polypropylene high-rate conductive microporous foam masterbatch foaming process is specifically as follows:

[0030] The polypropylene high-rate conductive microporous foam masterbatch is put into a foaming reactor, and then the foaming agent is continuously introduced into the foaming reactor and heated and pressurized. When the set temperature and pressure are reached, the pressure is quickly released to obtain a polypropylene conductive microporous foam material; the polypropylene conductive microporous foam material is pre-pressurized with air to store high-pressure air inside, and then secondary foaming is performed to obtain a polypropylene high-rate conductive microporous foam material.

[0031] Preferably, the foaming agent is one or more of carbon dioxide and nitrogen.

[0032] Preferably, the set temperature and pressure are: 140-160°C, 1-4 MPa.

[0033] Preferably, the rapid pressure relief method is: when the temperature and pressure reach the set value, the material release valve is opened to start foaming. During this process, the pressure in the foaming reactor is maintained unchanged, so that the material is continuously released from the reactor.

[0034] Preferably, the air pre-compression pressure is 0.6-0.8 MPa, and the time is 20-40 hours.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. In the present invention, graphene oxide is used as a conductive filler. The dispersibility of the amino-modified graphene oxide obtained by modification with γ-aminopropyltriethoxysilane is better. At the same time, as an inorganic particle, adding it to a polypropylene material will improve the mechanical properties. The siloxane group in γ-aminopropyltriethoxysilane has very high thermal stability and high temperature resistance. Its introduction increases the thermal stability of the matrix material, reduces the thermal decomposition of the material, and improves stability. The amino group in the amino-modified graphene oxide reacts with the aldehyde group in 3-(2-methoxyphenyl)-2-propenal to generate a carbon-nitrogen double bond to obtain modified graphene oxide. At the same time, the conjugated structure contained in 3-(2-methoxyphenyl)-2-propenal is conducive to electron transfer; the modified graphene oxide contains unsaturated carbon-carbon double bonds. Under the action of ammonium persulfate, it is further in-situ polymerized with aniline to obtain polyaniline-grafted graphene oxide. As a conductive organic substance, polyaniline is added to improve conductivity. The nucleating agent used in the present invention helps to control the size and distribution of micropores during the foaming process, thereby improving the conductivity and foaming uniformity of the material; the maleic anhydride grafted SBS has the function of a compatibilizer, and SBS itself is a copolymer and can be used as a toughening agent to further improve the toughness of the base material.

[0037] 2. The polypropylene high-ratio conductive microporous foaming masterbatch foaming process provided by the present invention realizes a finer microporous structure and a higher porosity through secondary foaming of the polypropylene high-ratio conductive microporous foaming masterbatch, effectively improving the performance of the material. All reaction steps and material selections in the present invention use environmentally friendly chemicals and processes, meeting the requirements of green manufacturing. At the same time, the polypropylene high-ratio conductive microporous foaming masterbatch provided by the present invention does not contain a foaming agent, avoiding the problem of the foaming agent causing failure and premature decomposition during the melt blending process, thereby affecting the later foaming performance. This masterbatch not only solves the problem of dispersion of functional components, but also facilitates the precise regulation of material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a process flow chart for preparing the polypropylene high-rate conductive microporous foam masterbatch of the present invention;

[0039] Figure 2 Schematic diagram of the reaction for preparing modified graphite oxide in the present invention. DETAILED DESCRIPTION

[0040] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0041] Example 1

[0042] This embodiment provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0043] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2000:80:40, heated at 25°C for reaction for 5 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 60°C for 10 hours to obtain modified graphene oxide;

[0044] Step (2) dispersing the modified graphene oxide into a 50 wt% ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 1 with a 1 mol / L hydrochloric acid aqueous solution, stirring and reacting at 20° C. for 18 h, filtering and washing with deionized water until neutral, and drying at 50° C. for 12 h to obtain polyaniline-grafted graphene oxide;

[0045] Among them, the modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate are in a mass ratio of 60:2500:250:140;

[0046] Step (3) Under nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano calcium carbonate, antioxidant 168, zinc stearate and polyaniline grafted graphene oxide are mixed in an extruder in a mass ratio of 70:5:3:0.5:1:2, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0047] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0048] Example 2

[0049] This embodiment provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0050] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2200:85:45, heated at 27°C for reaction for 4.5 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 62°C for 9.5 hours to obtain modified graphene oxide;

[0051] Step (2) dispersing the modified graphene oxide into a 50 wt% ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 1 with a 1 mol / L hydrochloric acid aqueous solution, stirring and reacting at 22° C. for 17.3 h, and after the reaction is completed, filtering and washing with deionized water until neutral, and drying at 52° C. for 11.5 h to obtain polyaniline-grafted graphene oxide;

[0052] Among them, the mass ratio of modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate is 65:3000:300:160;

[0053] Step (3) Under nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano calcium carbonate, antioxidant 168, zinc stearate and polyaniline grafted graphene oxide are mixed in an extruder in a mass ratio of 73:6.7:4.2:0.8:1.5:3, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0054] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0055] Example 3

[0056] This embodiment provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0057] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2400:90:50, heated at 30°C for reaction for 4 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 65°C for 9 hours to obtain modified graphene oxide;

[0058] Step (2) dispersing the modified graphene oxide into a 50 wt% ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 2 with a 1 mol / L hydrochloric acid aqueous solution, stirring and reacting at 25°C for 16.5 hours, and after the reaction is completed, filtering and washing with deionized water until neutral, and drying at 55°C for 11 hours to obtain polyaniline-grafted graphene oxide;

[0059] Among them, the mass ratio of modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate is 70:3500:350:180;

[0060] Step (3) Under nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano calcium carbonate, antioxidant 168, zinc stearate and polyaniline grafted graphene oxide are mixed in an extruder in a mass ratio of 77:8.5:5.5:1.2:2:4, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0061] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0062] Example 4

[0063] This embodiment provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0064] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2600:95:55, heated at 32°C for reaction for 3.5 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 68°C for 8.5 hours to obtain modified graphene oxide;

[0065] Step (2) dispersing the modified graphene oxide into a 50 wt% ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 3 with a 1 mol / L hydrochloric acid aqueous solution, stirring and reacting at 28°C for 15.8 hours, and after the reaction is completed, filtering and washing with deionized water until neutral, and drying at 57°C for 10.5 hours to obtain polyaniline-grafted graphene oxide;

[0066] The modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate are in a mass ratio of 75:4000:400:200;

[0067] Step (3) Under a nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano-calcium carbonate, antioxidant 168, zinc stearate and polyaniline grafted graphene oxide are mixed in an extruder in a mass ratio of 71:10.2:6.7:1.6:2.5:5, extruded, drawn, pelletized, and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0068] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0069] Example 5

[0070] This embodiment provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0071] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2800:100:60, heated at 35°C for reaction for 3 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 70°C for 8 hours to obtain modified graphene oxide;

[0072] Step (2) dispersing the modified graphene oxide into a 50 wt% ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 3 with a 1 mol / L hydrochloric acid aqueous solution, stirring and reacting at 30°C for 15 hours, filtering after the reaction, washing with deionized water until neutral, and drying at 60°C for 10 hours to obtain polyaniline-grafted graphene oxide; wherein the modified graphene oxide, the ethanol aqueous solution, the aniline and the ammonium persulfate are in a mass ratio of 80:4500:450:220;

[0073] Step (3) Under a nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano-calcium carbonate, antioxidant 168, zinc stearate and polyaniline grafted graphene oxide are mixed in an extruder in a mass ratio of 85:12:8:2:3:6, extruded, drawn, pelletized, and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0074] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0075] Example 6

[0076] This embodiment provides a method for preparing amino-modified graphene oxide, comprising the following steps:

[0077] Graphene oxide, anhydrous ethanol and γ-aminopropyltriethoxysilane were mixed uniformly in a mass ratio of 40:1000:10, reacted at 65°C for 5 hours, and after the reaction was completed, centrifuged, washed, and dried at 80°C for 4 hours to obtain amino-modified graphene oxide.

[0078] Comparative Example 1

[0079] This comparative example provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0080] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2000:80:40, heated at 25°C for reaction for 5 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 60°C for 10 hours to obtain modified graphene oxide;

[0081] Step (2) in a nitrogen environment, polypropylene, maleic anhydride grafted SBS, nano calcium carbonate, antioxidant 168, zinc stearate and modified graphene oxide are mixed in an extruder at a mass ratio of 70:5:3:0.5:1:2, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0082] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0083] Comparative Example 2

[0084] This comparative example provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0085] Step (1) anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal are mixed uniformly in a mass ratio of 2000:80:40, heated at 25°C for reaction for 5 hours, and after the reaction is completed, filtered, washed, and dried in a vacuum drying oven at 60°C for 10 hours to obtain modified graphene oxide;

[0086] Step (2) in a nitrogen environment, polypropylene, nano-calcium carbonate, antioxidant 168, zinc stearate and modified graphene oxide are mixed in an extruder in a mass ratio of 75:3:0.5:1:2, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foaming masterbatch;

[0087] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0088] Comparative Example 3

[0089] This comparative example provides a method for preparing a polypropylene high-rate conductive microporous foam masterbatch, comprising the following steps:

[0090] Under a nitrogen environment, polypropylene, antioxidant 168, zinc stearate and modified graphene oxide were mixed in an extruder at a mass ratio of 78:0.5:1:2, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foam masterbatch;

[0091] Among them, the temperature of each zone of the extruder is basically controlled at 180°C, and the length of the masterbatch is 2mm.

[0092] The amino-modified graphene oxide in Examples 1-5 of the present invention and Comparative Examples 1-3 all adopt the amino-modified graphene oxide prepared in Example 6.

[0093] In the examples and comparative examples of the present invention, polypropylene was obtained from Sinopec Yanshan Petrochemical Co., Ltd., model: K8303, with a density of 0.9 g / cm 3Maleic anhydride-grafted SBS was from Guangzhou Huiwangcheng Chemical Co., Ltd.; 3-(2-methoxyphenyl)-2-propenal was from Shanghai Haohong Biotechnology Co., Ltd., CAS No.: 60125-24-8; graphene oxide was from Anhui Kerun Nanotechnology Co., Ltd., nanostructured, purity: 99.9%; aniline was from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No.: 62-53-3.

[0094] Performance Testing

[0095] The polypropylene high-ratio conductive microporous foam masterbatch prepared in Examples 1-5 and Comparative Examples 1-3 was put into a foaming reactor, and then nitrogen gas as a foaming agent was continuously introduced into the foaming reactor and heated and pressurized. When the set temperature reached 150° C. and the pressure reached 2 MPa, the material release valve was opened to start foaming. During this process, the pressure in the foaming reactor was maintained unchanged, so that the material was continuously released from the reactor and the pressure was quickly released to obtain a polypropylene conductive microporous foam material; the polypropylene conductive microporous foam material was pre-pressurized with air to 0.6 MPa and maintained at this pressure for 20 hours to store high-pressure air inside. , and then secondary foaming was performed to obtain polypropylene high-rate conductive microporous foam materials, which were respectively recorded as samples 1-8; the cell density test was specifically as follows: a scanning electron microscope was used to observe the cross section, a middle section was taken as a sample, and Image-J software was used to count and calculate the average cell diameter and cell density distribution law, and the number of cells was calculated. Each group was repeated 3 times and the average value was recorded; the conductivity test: the polypropylene high-rate conductive microporous foam materials in samples 1-8 were respectively made into 20mm×10mm×4mm rectangular blocks, and the DC conductivity of the composite materials was tested according to the standard ASTM 257. Each group was repeated 3 times and the average value was recorded; the tensile performance test: the polypropylene high-rate conductive microporous foam materials in samples 1-8 were subjected to a tensile test at a rate of 50mm / min in accordance with the GB / T1040-2006 standard, repeated 5 times and the average value was recorded. The specific test results are shown in Table 1;

[0096] Table 1

[0097] Test items Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 <![CDATA[Cell density (10 8 cells / cm 3 )]]> 7.1 7.5 7.9 8.4 7.8 7.2 2.5 0.4 <![CDATA[Conductivity (10 -7 S / cm)]]> 5.6 6.2 6.9 7.5 7.9 2.4 0.48 0.46 Tensile strength (MPa) 42.2 42.7 43.3 43.8 44.4 41.6 36.9 34.5

[0098] According to the test results in Table 1, the polypropylene conductive microporous foamed material prepared by the present invention using intermittent physical foaming not only has the characteristics of high-rate foaming, but also has good conductivity and tensile properties, and the optimal cell density reaches 10 8 pieces / cm 3 , the conductivity can reach 10 -7 S / cm, and the maximum tensile strength can reach 44.4MPa.

[0099] As shown in Table 1, the cell density initially increases and then decreases. This is because modified graphene oxide provides more sites for cell nucleation, resulting in better dispersibility and a greater tendency to provide sites. Furthermore, the formation of polyaniline-grafted graphene oxide enhances melt viscosity, promoting stable cell growth. However, excessive dosage leads to excessive melt viscosity, inhibiting gas diffusion and consequently decreasing cell density. Comparative Example 1: Compared to Example 1, the modified graphene oxide lacks polyaniline grafting, resulting in poor dispersibility and fewer nucleation sites. Sample 6 exhibits lower cell density. Comparative Example 2: Compared to Comparative Example 1, the matrix compatibility is insufficient due to the lack of maleic anhydride-grafted SBS, which increases the probability of cell merging. Consequently, Sample 7 exhibits lower cell density. Comparative Example 3: Compared to Comparative Example 2, the nucleating agent nano-calcium carbonate is absent, resulting in lower nucleation efficiency and consequently lower foaming performance in Sample 8. Sample 6 exhibits lower electrical conductivity than Sample 1. This is because Comparative Example 1 lacks polyaniline grafting, relying solely on the flake structure of graphene oxide, which reduces conductive pathways and naturally reduces electrical conductivity. Compared to Comparative Example 1, Comparative Example 2 lacked a compatibilizer, resulting in severe agglomeration of the conductive filler, hindered electron transport, and reduced conductivity. Compared to Example 1, the graphene oxide in Comparative Example 1 was not grafted with polyaniline, resulting in insufficient dispersibility and limited reinforcement. Compared to Comparative Example 1, Comparative Example 2 lacked a compatibilizer, resulting in weak interfacial bonding between the matrix and filler, prone to debonding and fracture under stress, and detrimental to tensile properties. Compared to Comparative Example 2, Comparative Example 3 lacked the inorganic nano-calcium carbonate particles, resulting in reduced improvement in tensile properties.

[0100] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a polypropylene high-rate conductive microporous foam masterbatch, characterized in that: The following steps are involved: Step (1) mixing anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal uniformly, heating to react, and after the reaction is completed, filtering, washing, and vacuum drying to obtain modified graphene oxide; Step (2) dispersing the modified graphene oxide in an ethanol aqueous solution, adding aniline and ammonium persulfate after uniform dispersion, adjusting the pH to 1-3, stirring, reacting, filtering after the reaction, washing with deionized water until neutral, and drying to obtain polyaniline-grafted graphene oxide; Step (3) In a nitrogen environment, polypropylene, maleic anhydride grafted SBS, a nucleating agent, an antioxidant, a lubricant and polyaniline grafted graphene oxide are mixed in an extruder, extruded, drawn, pelletized and dried to obtain a polypropylene high-rate conductive microporous foaming masterbatch.

2. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (1), the mass ratio of anhydrous ethanol, amino-modified graphene oxide and 3-(2-methoxyphenyl)-2-propenal is (2000-2800):(80-100):(40-60).

3. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (2), the mass ratio of modified graphene oxide, ethanol aqueous solution, aniline and ammonium persulfate is (60-80):(2500-4500):(250-450):(140-220).

4. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (3), the mass ratio of polypropylene, maleic anhydride grafted SBS, nucleating agent, antioxidant, lubricant and polyaniline grafted graphene oxide is (70-85):(5-12):(3-8):(0.5-2):(1-3):(2-6).

5. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (3), the nucleating agent is one or more of nano calcium carbonate, nano montmorillonite and nano talc.

6. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (3), the antioxidant is one of antioxidant 168 and antioxidant 1010.

7. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (3), the lubricant is zinc stearate.

8. The method for preparing a polypropylene high-rate conductive microporous foam masterbatch according to claim 1, characterized in that: In the step (3), the density of polypropylene is 0.9 g / cm 3 .

9. A polypropylene high-rate conductive microporous foam masterbatch, characterized in that: The polypropylene high-rate conductive microporous foam masterbatch is prepared by the preparation method of any one of claims 1 to 8.

10. A polypropylene high-rate conductive microporous foam material, characterized in that: The polypropylene high-rate conductive microporous foam masterbatch according to claim 9 is foamed.

Images