Graphene reinforced POE elastomer composition and preparation method thereof

Abstract

The invention provides a graphene reinforced POE elastomer composition and a preparation method thereof, and belongs to the technical field of graphene / polyolefin composite materials. Through precise cooperation of all the components, optimization and improvement of the performance of the POE elastomer are achieved. 85-95 parts of the POE matrix with specific melt index and density are adopted, so that good processability is ensured while the flexibility of the material is kept; 1-5 parts of redox graphene with specific sheet diameter and functional groups effectively construct a mechanical and heat-conducting network; 2-9 parts of maleic anhydride grafted POE compatilizer are bridged through a strong interface, so that agglomeration and phase separation of graphene are prevented; 0.5-2 parts of an efficient antioxidant is supplemented, so that the thermal oxidation stability of the material is guaranteed; the composition has excellent comprehensive performance, and is especially suitable for the fields with strict requirements on flexibility and reliability, such as photovoltaic packaging, automobile sealing and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of graphene / polyolefin composites, and particularly relates to a graphene-reinforced POE elastomer composition and a preparation method. BACKGROUND

[0002] POE (polyolefin elastomer) is a kind of high-performance thermoplastic elastomer, which is widely used in photovoltaic encapsulation film, automobile sealing, wire and cable insulation layer and other fields due to its excellent flexibility, low-temperature resistance, weather resistance and good compatibility with polyolefin materials. With the development of new energy and high-end manufacturing industries, higher requirements are put forward for the mechanical strength, thermal conductivity and anti-aging performance of POE materials. It is difficult to meet the demand by relying solely on the performance of POE, and modification by nano-filler has become a key way to improve the comprehensive performance.

[0003] Graphene, as a two-dimensional nanomaterial with ultra-high mechanical strength (tensile strength 130 GPa) and excellent thermal conductivity (in-plane thermal conductivity 5300 W / (m·K)), is considered to be an ideal functional filler for POE modification. However, in the research and production of graphene-reinforced POE elastomers, the following core technical problems generally exist: Poor dispersion of graphene, large performance fluctuation: graphene layers have strong van der Waals forces between them, which easily leads to agglomeration. Simple mechanical mixing (such as direct melt blending) is difficult to achieve uniform dispersion of graphene in the POE matrix. Agglomerated graphene not only cannot play the role of reinforcement and thermal conductivity, but also becomes a stress concentration point in the material, leading to a decrease in mechanical properties such as tensile strength and elongation at break, and the performance deviation of different batches of products often exceeds 10%, seriously affecting large-scale application.

[0004] Insufficient interface compatibility, limited function: POE is a non-polar polyolefin segment structure, while graphene has polar functional groups such as hydroxyl (-OH) and carboxyl (-COOH) on its surface after oxidation and reduction treatment. The interface polarity difference between them is large, and the compatibility is poor. This leads to weak interfacial adhesion between graphene and POE matrix, which is prone to interfacial peeling under external force. Not only is the mechanical reinforcement effect limited (the tensile strength improvement is usually less than 15%), but also the thermal conductivity network of graphene is difficult to effectively build (the thermal conductivity coefficient improvement is less than 30%).

[0005] The unsaturated bond exists in the POE molecular chain, and is easy to be oxidized and degraded under the action of light, heat and oxygen, and the introduction of graphene may accelerate this process: on the one hand, the undispersed graphene agglomerates may become active sites for photocatalytic degradation; on the other hand, the synergistic effect design of the existing formula of antioxidants, graphene and POE is insufficient, so that the tensile strength retention rate of the material is usually less than 70% after xenon lamp aging for 1000h, which is difficult to meet the long service life scene requirements such as photovoltaic packaging (≥80%) and outdoor sealing of automobile.

[0006] Therefore, developing a kind of graphene reinforced POE elastomer composition that can realize uniform dispersion of graphene, good interface combination, stable improvement of mechanical and thermal conductivity performance and excellent anti-aging property has become the key to solving the above technical bottlenecks and promoting its large-scale application in high-end fields. SUMMARY

[0007] To solve the above technical problems of the prior art, the present application aims to provide a graphene reinforced POE elastomer composition and a preparation method.

[0008] One of the purposes of the present application is to provide a graphene reinforced POE elastomer composition, which comprises the following raw materials in parts by weight: POE elastomer particles: 85-95 parts, the melt flow rate of the POE elastomer particles is 5-20 g / 10 min, and the density is 0.87-0.89 g / cm 3 ; Redox graphene: 1-5 parts, the flake diameter of the redox graphene is 1-5 μm, the thickness is 1-5 nm, the surface oxygen-containing functional group content is 5-15 at%, and the ash content is ≤0.5%; Compatibilizer: 2-9 parts, the compatibilizer is maleic anhydride grafted POE, the maleic anhydride grafting rate is 0.5-2.0%, the melt flow rate is 10-30 g / 10 min, and the thermal decomposition temperature is ≥250°C; Antioxidant: 0.5-2 parts, the antioxidant is a hindered phenolic antioxidant and / or a phosphite antioxidant.

[0009] Preferably, the maleic anhydride grafted POE is a gradient grafting compound system, which comprises high grafting MAH-g-POE with a grafting rate of 1.5-2.0% and low grafting MAH-g-POE with a grafting rate of 0.5-1.2% in a mass ratio of 2-4:1.

[0010] Preferably, the POE elastomer particles are ethylene-octene copolymer, in which the mass content of octene is 20-30%, and preferably Exxon Mobil 8780.

[0011] Preferably, the oxidized-reduced graphene is prepared by a modified Hummers method, and the molar ratio of hydroxyl and carboxyl in the oxidized-reduced graphene is 3-5:1. Preferably, the antioxidant is a hindered phenol and a phosphite, and preferably a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1-2:1. Preferably, the raw material further comprises 1-3 parts of hexagonal boron nitride, the hexagonal boron nitride has a flake diameter of 3-8 μm, a thickness of 3-8 nm, a purity of ≥99%, and a volume resistivity of ≥10 16 Ω·cm.

[0012] The second object of the present application is to provide a preparation method of a graphene-reinforced POE elastomer composition, the preparation method comprising: (1) Pre-dispersion treatment First, add the oxidized-reduced graphene, maleic anhydride grafted POE, and hexagonal boron nitride into a high-speed stirring tank; Then, turn on the ultrasonic oscillation with a frequency of 20-40 kHz and a power of 300-500 W, and simultaneously stir at a speed of 1800-2500 r / min for 15-30 min, and the dispersion degree of the graphene is ≥90%; Then, add the antioxidant, and stir at a low speed of 500-800 r / min for 5-10 min to obtain a graphene pre-dispersion system; (2) Melt blending and extrusion Use a double-screw extruder, and the barrel sequentially comprises a feeding section at 140-160℃, a melting section at 160-180℃, and a homogenization section at 170-190℃ according to the material flow direction, the screw rotation speed is 300-500 r / min, and the vacuum degree is -0.08--0.09 MPa; Add the POE elastomer particles into the extruder through the main feeding port at a rate of 20-30 kg / h, and after the POE elastomer particles are completely melted, add the graphene pre-dispersion system through the side feeding port at a rate of 2-5 kg / h; After the melt mixture is sheared and mixed by the double-screw extruder, a continuous elastomer strip is extruded from the die; (3) Granulation and shaping Introduce the elastomer strip into underwater cutting, set the cutting rotation speed to 800-1200 r / min, the cutting diameter to 2-3 mm, the cooling water temperature to 20-30℃, and the cooling water pressure to 0.2-0.3 MPa, and after cutting, dry and sieve to obtain the graphene-reinforced POE elastomer composition.

[0013] Preferably, a mixing section and an exhaust section are further sequentially arranged between the melting section and the homogenization section, the temperature of the mixing section is 160-180℃, and the temperature of the exhaust section is 160-180℃. The length percentages of each section are as follows: feeding section 20%, melting section 30%, mixing section 25%, venting section 15%, and homogenization section 10%.

[0014] Preferably, in step (3), a gradient heating mode is used for drying: first dry at 80℃ for 5 minutes, then heat to 100℃ and dry for 5~10 minutes.

[0015] Preferably, in step (1), when hexagonal boron nitride is added, the ultrasonic oscillation frequency is adjusted to 30~35kHz, the stirring speed is adjusted to 2200~2500r / min, and the pre-dispersion time is extended to 20~25min.

[0016] The beneficial effects of this invention include: This invention achieves an excellent balance between processing performance, mechanical properties, thermal conductivity, and long-term durability in graphene-reinforced POE elastomer compositions through precise design and synergistic coordination of each component and its parameters. Specifically, using 85-95 parts of POE elastomer with a specific melt index and density as the matrix ensures the flexibility and processing fluidity of the material core, providing stable support for functional performance; 1-5 parts of reduced graphene oxide (rGO) with specific sheet size, thickness, and surface functional group content serve as the functional core, effectively constructing a continuous mechanical reinforcement and thermal conductivity network while avoiding agglomeration and processing difficulties caused by excessive addition; 2-9 parts of maleic anhydride-grafted POE compatibilizer with suitable grafting rate, melt index, and high thermal decomposition temperature form a strong interfacial bridge between rGO and the POE matrix, significantly improving interfacial bonding and preventing the exfoliation of the functional phase; supplemented with 0.5-2 parts of highly efficient hindered phenolic and / or phosphite antioxidants, effectively inhibiting the aging of the material under thermo-oxidative conditions. This composition is particularly suitable for applications such as photovoltaic encapsulation and automotive sealing, which have stringent requirements for material flexibility, reliability, and functionality, and shows broad application prospects. Detailed Implementation

[0017] The following description includes certain specific details to provide a comprehensive understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented without employing one or more of these specific details, but using other methods, components, materials, etc.

[0018] Unless otherwise required by the present invention, throughout the specification and the following claims, the words “comprising” and “including” shall be interpreted in an open-ended, inclusive sense, meaning “including but not limited to”.

[0019] Throughout this specification, the terms "an embodiment," "an embodiment," "a preferred embodiment," or "some embodiments" refer to including, in at least one embodiment, a specific reference element, structure, or feature associated with that embodiment. Therefore, the phrases "in an embodiment," "in a preferred embodiment," or "in some embodiments" appearing in different places throughout the specification do not necessarily all refer to the same embodiment. Furthermore, specific elements, structures, or features may be combined in one or more embodiments in any suitable manner.

[0020] According to a first aspect of the present invention, a graphene-reinforced POE elastomer composition is provided, the POE elastomer composition comprising the following raw materials in parts by weight: POE elastomer particles: 85-95 parts, wherein the melt flow rate of the POE elastomer particles is 5-20 g / 10 min, and the density is 0.87-0.89 g / cm³. 3 ; Reduced graphene oxide: 1-5 parts, wherein the reduced graphene oxide has a sheet diameter of 1-5 μm, a thickness of 1-5 nm, a surface oxygen-containing functional group content of 5-15 at%, and an ash content ≤0.5%; Compatibilizer: 2-9 parts, wherein the compatibilizer is maleic anhydride-grafted POE (MAH-g-POE), with a maleic anhydride grafting rate of 0.5-2.0%, a melt flow rate of 10-30 g / 10 min, and a thermal decomposition temperature ≥250℃; Antioxidant: 0.5 to 2 parts, wherein the antioxidant is a hindered phenolic antioxidant and / or a phosphite antioxidant.

[0021] In this invention, POE elastomer particles serve as the matrix of the composite material. If the weight percentage is less than 85 parts, the proportion of functional components such as graphene and compatibilizers is too high, which will damage the elastomeric properties of the POE matrix and negate the core advantage of POE as a flexible material. If the weight percentage is greater than 95 parts, the concentration of graphene and compatibilizers is too low, making it difficult to form a continuous mechanical or thermal network and easily leading to interfacial bonding failure. A range of 85-95 parts is beneficial for achieving a balance between preserving the elasticity of the POE matrix and effectively utilizing the functional components, making it suitable for applications requiring flexibility, such as photovoltaic encapsulation and automotive sealing. The POE elastomer particles are, for example, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or 95 parts.

[0022] The standard for testing the melt flow rate of POE elastomer particles is GB / T 3682.1-2018, with test conditions of 190℃ and a load of 2.16kg. A melt flow rate of 5~20g / 10min balances "processing fluidity" and "matrix mechanical basis," ensuring thorough mixing with functional components during melt blending while providing stable matrix support for the mechanical reinforcement of graphene. If the melt flow rate is below 5g / 10min, the POE melt viscosity is too high, making it difficult to mix uniformly with the graphene pre-dispersion system and prone to local unmelted agglomeration; at the same time, high viscosity leads to increased extrusion energy consumption, which is not conducive to large-scale production. If the melt flow rate is above 20g / 10min, the POE molecular chain is too short, which may result in insufficient mechanical strength.

[0023] The density of POE elastomer particles is 0.87~0.89 g / cm³. 3 This facilitates adaptation to the diverse performance requirements of the matrix in various scenarios. If the density is below 0.87 g / cm³... 3 When the α-olefin content is too high and the crystallinity of POE is too low, the material's hardness and resistance to compressive deformation decrease; when the density is higher than 0.89 g / cm³, the material's hardness and resistance to compressive deformation also decrease. 3 When the ethylene content is too high, the crystallinity of POE is too high, which will lead to a significant reduction in flexibility.

[0024] In this invention, reduced graphene oxide (rGO) is the core source of mechanical enhancement and thermal conductivity. An addition of 1-5 parts per unit weight is beneficial for the physical support of the rGO sheets and the establishment of thermal conduction pathways, while avoiding agglomeration problems caused by excessive addition. If the weight is less than 1 part per unit weight, rGO is difficult to form a continuous "sheet network" in the POE matrix, resulting in poor improvement in mechanical and thermal conductivity properties. If the weight is greater than 5 parts per unit weight, the van der Waals forces between the rGO sheets are significantly enhanced, which may lead to secondary agglomeration during processing, forming stress concentration points internally, and potentially causing a sharp increase in melt viscosity, making extrusion processing difficult. Examples of rGO amounts include 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts, and any values ​​between these two ranges.

[0025] A rGO flake diameter of 1–5 μm is beneficial for its better dispersion in the matrix and the construction of functional networks. If the flake diameter is <1 μm, the rGO flakes are too small, making it difficult to form a continuous mechanical support network and thermally conductive network; if the flake diameter is >5 μm, the aspect ratio of the rGO flakes is too large, making them prone to entanglement and agglomeration in the POE melt during the preparation process. Examples of rGO flake diameters include 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 5 μm, as well as any values ​​between these two ranges.

[0026] A rGO thickness of 1-5 nm is beneficial for its better dispersion in the POE matrix. A thickness greater than 5 nm increases the van der Waals forces between rGO layers, significantly increasing the difficulty of peeling. Even after ultrasonic treatment, it remains in a multi-layered stacked state, resulting in decreased thermal conductivity and mechanical enhancement. A thickness less than 1 nm is more expensive, and single-layer sheets are prone to structural defects (such as edge cracking) due to ultrasonic treatment, leading to unstable performance. rGO thicknesses include, for example, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, or 5 nm, and any values ​​between these ranges.

[0027] The oxygen-containing functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups on the surface of rGO serve as "interfacial active sites" for its binding with the compatibilizer (MAH-g-POE). The content of oxygen-containing functional groups on the surface is obtained by X-ray photoelectron spectroscopy (XPS). If the content of oxygen-containing functional groups is <5 at%, there are insufficient active sites, resulting in weak interfacial bonding. During stretching, rGO is easily peeled off from the POE matrix, leading to poor mechanical reinforcement. If the content of oxygen-containing functional groups is >15 at%, the conjugated carbon skeleton of rGO is excessively oxidized and destroyed, significantly reducing its intrinsic thermal conductivity. Furthermore, the high functional group content leads to increased hydrophilicity of rGO, which in turn reduces its compatibility with nonpolar POE, making phase separation more likely. The surface oxygen-containing functional group content of rGO is, for example, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%, and any value between these values.

[0028] The ash content of rGO mainly originates from residual metal catalysts (such as K and Mn salts in the Hummers process) and incompletely exfoliated graphite particles during the preparation process. The ash content can be obtained by muffle furnace calcination (calcination at 800℃ for 2 hours). If the ash content is >0.5%, the residual metal salts will accelerate the oxidative degradation of POE and accelerate the aging of the material under thermo-oxidative conditions. At the same time, graphite particles can easily cause the thermal conductivity network constructed by rGO to be interrupted, which can lead to insufficient improvement in the thermal conductivity of the composite material.

[0029] In this invention, the compatibilizer is maleic anhydride-grafted POE (MAH-g-POE), mainly acting as an interfacial bridging agent. If its weight part is less than 2 parts, the compatibilizer is difficult to fully coat the rGO surface, and the exposed surface is prone to re-aggregation. If its weight part is greater than 9 parts, the proportion of polar maleic anhydride groups in MAH-g-POE is too high, which can easily destroy the non-polar environment of the POE matrix, thereby reducing the weather resistance of the composite material and increasing the material cost. The compatibilizer is, for example, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, or 9 parts, and any value between any two of the above.

[0030] Preferably, the mass ratio of rGO to compatibilizer is 1:1.6 to 3, which ensures that each rGO layer is fully coated with compatibilizer while avoiding performance and cost problems caused by excessive addition. The mass ratio is, for example, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, or 1:3, and any value between any two of the above, preferably 1:2.

[0031] The maleic anhydride grafting rate of 0.5-2.0% refers to the result determined by acid-base titration. If the grafting rate is <0.5%, there are too few maleic anhydride groups on the MAH-g-POE molecular chain, resulting in insufficient binding sites with oxygen-containing functional groups on the rGO surface, weak interfacial bonding, and easy rGO-matrix peeling, leading to poor elongation at break of the composite material. If the grafting rate is >2.0%, the polarity of MAH-g-POE is too strong, reducing its compatibility with the non-polar POE matrix. Phase separation may occur during melt blending in the preparation process, easily leading to fluctuations in the mechanical properties of the material.

[0032] The melt flow rate (MFR) of MAH-g-POE was measured at 190℃ / 2.16kg. It needs to be matched with the POE matrix to ensure consistent flowability during melt blending. If the MFR < 10g / 10min, the melt viscosity of the compatibilizer is higher than that of the POE matrix, and high-viscosity agglomerates are easily formed during mixing, which cannot be uniformly dispersed in the POE melt, resulting in a decrease in the encapsulation efficiency of rGO. If the MFR > 30g / 10min, the molecular chains of the compatibilizer are too short, and the molecular entanglement with the POE matrix is ​​weak, which will lead to a decrease in interfacial bonding strength, and thus a decrease in the fatigue resistance of the composite material.

[0033] The thermal decomposition temperature of MAH-g-POE refers to the 5% thermal decomposition temperature (T) under a nitrogen atmosphere. d5 The thermal decomposition temperature (TGA), measured under a nitrogen atmosphere, corresponds to the temperature at which the material mass loss reaches 5% of the initial mass. The TGA temperature must be higher than the maximum processing temperature of the melt blend to avoid degradation of the compatibilizer during processing. If the TGA temperature is <250℃, MAH-g-POE may undergo thermal degradation during preparation, leading to the detachment of maleic anhydride groups and loss of interfacial bridging effect. Simultaneously, the small molecule volatiles generated by degradation will form bubbles in the composite material, affecting its mechanical and thermal conductivity.

[0034] In this invention, the antioxidant is an anti-aging protective agent for the composition. If the antioxidant's weight part is less than 0.5 parts, the antioxidant concentration is too low, making it difficult to effectively capture free radicals generated by POE degradation, thus accelerating the aging rate of the material under thermo-oxidative conditions. If the weight part is greater than 2 parts, the antioxidant is prone to migrate and precipitate from the POE matrix (especially under high-temperature conditions), leading to a decrease in the anti-aging effect over time and affecting the surface properties of the composite material. The antioxidant is, for example, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2 parts, and any value between these two.

[0035] In this invention, the antioxidant is, for example, a hindered phenolic antioxidant, a phosphite antioxidant, or a combination of a hindered phenolic antioxidant and a phosphite antioxidant. These two types of antioxidants exhibit excellent compatibility with POE and MAH-g-POE, preventing performance fluctuations caused by phase separation or migration precipitation, while also not affecting the dispersion and function of rGO.

[0036] In a preferred embodiment of the present invention, the maleic anhydride-grafted POE is a gradient grafting compound system, comprising a high-grafted MAH-g-POE with a grafting rate of 1.5-2.0% and a low-grafted MAH-g-POE with a grafting rate of 0.5-1.2% in a mass ratio of 2-4:1.

[0037] In this invention, highly grafted MAH-g-POE has dense maleic anhydride groups on its molecular chain, which is conducive to forming a strong interfacial bond with oxygen-containing functional groups on the graphene surface; low-grafted MAH-g-POE has weak polarity and good compatibility with the POE matrix. By using both highly grafted and low-grafted MAH-g-POE, both interfacial bonding ability and matrix compatibility can be guaranteed.

[0038] A mass ratio of 2–4:1 for high-grafted MAH-g-POE to low-grafted MAH-g-POE is beneficial for achieving a balance between interfacial bonding and matrix compatibility. If the ratio is <2:1, the proportion of low grafting is too high, resulting in insufficient high-graft compatibilizer and inadequate binding sites with graphene, increasing the risk of agglomeration. If the ratio is >4:1, the proportion of high grafting is too high, resulting in insufficient low-graft compatibilizer, high compatibilizer polarity, decreased system compatibility, increased risk of phase separation, and potential uneven graphene dispersion. A ratio of 2–4:1 ensures that the high-graft compatibilizer provides sufficient interfacial bonding, while the low-graft compatibilizer fills the remaining space and is compatible with the POE matrix, forming a continuous transition structure of "graphene-high-graft compatibilizer-low-graft compatibilizer-POE matrix." This helps eliminate interfacial abrupt changes and improves dispersion stability during processing. The mass ratio of high-grafted MAH-g-POE to low-grafted MAH-g-POE is, for example, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1 or 4:1, and any value between the two, preferably 3:1.

[0039] In a preferred embodiment of the present invention, the POE elastomer particles are ethylene-octene copolymers, wherein the octene mass content is 20-30%, preferably ExxonMobil 8780.

[0040] In this invention, compared with short-chain POEs such as ethylene-butene and ethylene-hexene, the long octene side chains of the ethylene-octene copolymer can better penetrate between rGO sheets, thereby more effectively reducing graphene agglomeration. On the one hand, the C8 side chain length of octene (approximately 0.8 nm) matches the thickness of the graphene sheets (1~5 nm). When graphene is dispersed in the POE matrix, the long side chains can interpenetrate between adjacent graphene sheets, better forming physical barriers and weakening the van der Waals forces between the sheets. On the other hand, the nonpolar carbon chains of the octene side chains can generate weak interactions (π-alkyl interactions) with the conjugated carbon skeleton of graphene through van der Waals forces, reducing the wetting angle of the POE matrix on the graphene sheets and further promoting the uniform dispersion of graphene in the substrate.

[0041] Meanwhile, the long side-chain structure of octene can more effectively weaken the regularity of ethylene segments, reduce the crystallinity of POE, and endow the material with better flexibility, low-temperature resistance and fatigue resistance.

[0042] In this invention, an octene content of 20-30% can balance mechanical properties and processability, which is beneficial for achieving a synergistic effect of flexibility, strength, and processability. If the octene content is <20%, the proportion of ethylene segments is too high, the molecular chain regularity is enhanced, the crystallinity is increased, resulting in increased material hardness, decreased flexibility, and increased melt viscosity, making it more difficult to mix with the graphene pre-dispersion system and prone to uneven dispersion. If the octene content is >30%, the proportion of octene side chains is too high, the molecular chain entanglement density is reduced, and the crystallinity is too low. Although the flexibility is good, the mechanical strength and resistance to compression deformation will decrease. At the same time, the low crystallinity will lead to insufficient POE melt strength, making the extrusion granulation strip prone to breakage and affecting processing stability.

[0043] Furthermore, when the octene content is 20-30%, the melt viscosity of POE (at 190℃) stabilizes at 100-200 Pa·s. This viscosity range is beneficial for the effective transfer of shear force to the graphene agglomerates during melt blending and extrusion, thereby more effectively tearing apart the agglomerates. Simultaneously, this content range corresponds to a POE crystallinity of 10-15%, with a low proportion of crystalline regions (hard segments), which reduces the probability of graphene being blocked by crystalline regions during dispersion, resulting in a smoother dispersion path for graphene.

[0044] In this invention, ExxonMobil 8780 has an octene content of approximately 25%, an MFR of 10 g / 10 min, and a density of 0.875 g / cm³. 3 Furthermore, the molecular chain distribution is narrow (molecular weight distribution index PDI = 2.5~3.0), and the melt viscosity fluctuation is ≤5%, which can ensure the stable mixing ratio with the graphene pre-dispersion system during the preparation process, avoid uneven graphene dispersion caused by matrix viscosity fluctuations, and ensure high batch consistency, which is beneficial to reducing production costs and quality risks.

[0045] In a preferred embodiment of the present invention, the reduced graphene is prepared by a modified Hummers process, and the molar ratio of hydroxyl to carboxyl groups in the reduced graphene is 3~5:1. In this invention, the modified Hummers process yields graphene with high purity, complete structure, and uniform functional group distribution, making it more suitable for use in this system. The hydroxyl and carboxyl groups on the surface of the graphene are the main active sites. The hydroxyl group (-OH) has moderate polarity (bond moment 1.56D) and readily forms hydrogen bonds (bond energy 20~30kJ / mol) with the maleic anhydride group (-CO-O-CO-) in MAH-g-POE. It also has low steric hindrance and can be uniformly distributed on the graphene sheet surface, forming stable "multi-point bonds." The carboxyl group (-COOH) has strong polarity (bond moment 1.76D) and high reactivity. It can undergo esterification reactions (covalent bonds, bond energy 300~400kJ / mol) with the maleic anhydride group in MAH-g-POE. However, the carboxyl group has high steric hindrance; if its content is too high, it will lead to excessive polarity on the graphene surface, reducing its compatibility with nonpolar POE. If the ratio is less than 3:1, the carboxyl group content is too high, resulting in excessively strong surface polarity of graphene. This increases the interfacial tension between graphene and the POE matrix, reduces compatibility, and makes it prone to localized enrichment due to polar repulsion during dispersion. If the ratio is greater than 5:1, the hydroxyl group content is too high. Although the polarity is moderate, there are insufficient covalent bonding sites, leading to decreased interfacial bonding with MAH-g-POE. This makes it difficult to effectively anchor graphene and also easily leads to secondary aggregation. The molar ratio of hydroxyl to carboxyl groups can be, for example, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, or 5:1, as well as any values ​​between these two.

[0046] In a preferred embodiment of the present invention, the antioxidant is a hindered phenol and a phosphite, preferably a compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1 to 2:1.

[0047] POE molecular chains are susceptible to degradation by heat, oxygen, and ultraviolet radiation. The photocatalytic effect of graphene accelerates the generation of free radicals, and single antioxidants are easily adsorbed by graphene and become ineffective. In this invention, the use of a combination of hindered phenols and phosphites is beneficial in addressing the dual aging mechanism of the composite system. The hindered phenolic antioxidant is the primary antioxidant, directly capturing free radicals generated by POE degradation and terminating the chain degradation reaction. Specifically, it reacts with the ·OH free radicals generated by rGO photocatalysis, reducing the attack of free radicals on the POE molecular chains. The phosphite antioxidant acts as a secondary antioxidant, decomposing the hydroperoxides (ROOH) generated by POE oxidation, preventing further decomposition into free radicals. It synergistically works with the hindered phenolic antioxidant to address the dual problems of rGO photocatalysis and the inherent heat and oxygen aging of POE.

[0048] In this invention, antioxidant 1010 is a quaternary hindered phenol (molecular weight 1178 g / mol), with a large molecular volume and strong steric hindrance, resulting in weak π-π stacking interaction with the graphene surface and low adsorption rate. Antioxidant 168 is a phosphite (molecular weight 646 g / mol), with a non-planar structure, making it difficult to bind to the conjugated surface of graphene, resulting in an adsorption rate of <10%. Both antioxidants 1010 and 168 have strong resistance to graphene adsorption. Furthermore, both antioxidants 1010 and 168 contain long-chain alkyl groups in their molecular chains, exhibiting good compatibility with the nonpolar segments of POE and making them less prone to migration and precipitation.

[0049] The ratio of antioxidant 1010 to antioxidant 168 is 1~2:1. By adjusting the concentrations of the two antioxidants, a balance is achieved between the "free radical generation rate" and the "hydrogen peroxide accumulation rate" in the composite system. If the ratio is <1:1, it is difficult to capture the large number of free radicals generated by graphene photocatalysis in time, resulting in a rapid decrease in tensile strength during the initial aging stage. If the ratio is >2:1, incomplete decomposition of hydrogen peroxide is likely, leading to secondary aging due to ROOH decomposition in the later stages of aging, resulting in a decrease in tensile strength retention. The 1~2:1 ratio ensures that the free radical capture rate of antioxidant 1010 matches the free radical generation rate of the graphene / POE system, and that the hydrogen peroxide decomposition rate of antioxidant 168 matches the ROOH accumulation rate, forming a closed-loop protection of front-end capture + back-end decomposition. The mixing ratio of antioxidant 1010 and antioxidant 168 is, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, and any point value between the two mentioned above, preferably 1.5:1.

[0050] In a preferred embodiment of the present invention, the raw material further includes 1-3 parts of hexagonal boron nitride, wherein the hexagonal boron nitride has a sheet diameter of 3-8 μm, a thickness of 3-8 nm, a purity of ≥99%, and a volume resistivity of ≥10. 16 Ω·cm.

[0051] In this invention, hexagonal boron nitride (h-BN) is used to synergistically construct a gapless thermally conductive network with graphene. Graphene (1~5μm) forms the basic thermally conductive path, and h-BN (3~8μm) bridges the gaps in the graphene. The synergy between the two can efficiently improve the thermal conductivity of the composite material, making it particularly suitable for applications requiring rapid heat conduction, such as photovoltaic films and automotive battery pack seals, which have high heat dissipation requirements. If the amount used is less than 1 part, h-BN is difficult to form a continuous thermally conductive auxiliary network in the matrix and can only fill a small number of gaps in the graphene thermally conductive network. If the amount used is greater than 3 parts, the van der Waals forces between h-BN sheets are significantly enhanced, making agglomeration more likely. Furthermore, an excessively high proportion of inorganic fillers will destroy the entangled structure of the POE molecular chains, leading to an increase in elongation at break and compression set, which may result in the loss of the flexibility advantage of POE. The hexagonal boron nitride is, for example, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, or 3 parts, as well as point values ​​between any two of the above.

[0052] The diameter of h-BN sheets is 3~8μm, slightly larger than that of graphene (1~5μm), which is beneficial for filling the network gaps between graphene sheets. In thermally conductive networks constructed from single graphene sheets, due to the small sheet diameter (≤5μm), gaps of 1~2μm are easily formed between adjacent sheets. The slightly larger size of h-BN can bridge these gaps, forming a continuous overlapping structure of graphene-h-BN-graphene. The few-layer structure of h-BN with a thickness of 3~8nm is beneficial for preserving its intrinsic thermal conductivity while avoiding the high cost and easy agglomeration problems of single-layer h-BN. If the thickness is >8nm, the thermal conductivity of h-BN drops sharply; if the thickness is <3nm, the sheets are prone to breakage due to excessive ultrasonic dispersion, losing their overlapping ability.

[0053] Furthermore, the size matching between graphene (1~5μm) and h-BN (3~8μm) can also prevent each other from agglomerating through steric hindrance. The slightly larger size of h-BN can be interspersed between graphene sheets to prevent graphene from re-agglomerating due to van der Waals forces. At the same time, graphene can also separate h-BN sheets to prevent h-BN agglomeration.

[0054] A purity of ≥99% helps eliminate "impurity interference," ensuring thermal conductivity and insulation stability. Volume resistivity ≥10 16Ω·cm helps reduce the potential electrical conductivity risk of graphene. Although graphene's primary function is thermal conductivity, its conjugated structure between layers gives it weak electrical conductivity. If it locally agglomerates in a POE matrix, it may lead to a decrease in the insulation of the composite material, making it unsuitable for applications requiring insulation. h-BN is a typical insulating and thermally conductive material, with its layers connected by weak van der Waals forces, making electron transfer across layers difficult. Adding h-BN can physically separate the graphene layers, preventing them from forming conductive pathways, while simultaneously not contributing conductivity itself, ensuring the overall insulation of the composite material meets the standards.

[0055] According to a second aspect of the present invention, a method for preparing a graphene-reinforced POE elastomer composition is provided, the method comprising: (1) Pre-dispersion treatment First, graphene oxide, maleic anhydride-grafted POE, and hexagonal boron nitride are added to a high-speed mixing tank. Then, ultrasonic oscillation with a frequency of 20~40kHz and a power of 300~500W is turned on, and the mixture is stirred at a speed of 1800~2500r / min for 15~30min, with a graphene dispersion of ≥90%. Then add antioxidants and stir at low speed (500-800 rpm) for 5-10 minutes to obtain a graphene pre-dispersion system.

[0056] In step (1), the hexagonal boron nitride is added according to application requirements.

[0057] In this invention, ultrasound at frequencies of 20–40 kHz generates localized high pressure and microjets through cavitation, which can tear apart graphene aggregates (especially large aggregates of 10–50 μm). Simultaneous high-speed stirring at 1800–2500 r / min creates a strong shear flow field. The synergistic effect of ultrasound and high-speed stirring rapidly disperses the ultrasonically exfoliated sheets into MAH-g-POE. When the ultrasound frequency is <20 kHz, the cavitation effect is weak, resulting in low exfoliation efficiency; when the ultrasound frequency is >40 kHz, the ultrasound energy is concentrated on the surface, making it difficult to reach deep aggregates. When the ultrasound power is <300 W, the energy is insufficient, leading to incomplete exfoliation; when the ultrasound power is >500 W, excessive ultrasound can cause graphene sheets to break. When the stirring speed is <1800 r / min, the shear flow field is weak, resulting in low dispersion efficiency; when the speed is >2500 r / min, it can easily cause a sudden increase in system temperature, potentially leading to premature softening and agglomeration of MAH-g-POE, hindering dispersion.

[0058] Stirring antioxidants at a low speed of 500-800 rpm can prevent the molecular chains from breaking due to shear forces caused by high-speed stirring. Low-speed stirring can achieve uniform dispersion without causing damage. After adding antioxidants, the system temperature should also be controlled to ≤50℃ during the stirring process.

[0059] (2) Melt blending extrusion The twin-screw extruder is used, with the barrel consisting of a feeding section (140~160℃), a melting section (160~180℃), and a homogenization section (170~190℃) in sequence according to the material flow direction. The screw speed is 300~500 r / min, and the vacuum degree is -0.08~-0.09 MPa. POE elastomer particles are added to the extruder through the main feed port at a rate of 20-30 kg / h. After the POE elastomer particles are completely melted, the graphene pre-dispersion system is added through the side feed port at a rate of 2-5 kg / h. After being sheared and mixed by a twin-screw extruder, the molten mixture is extruded from the die to form a continuous elastomer strip.

[0060] In this invention, segmented temperature control prevents premature melting and agglomeration of POE and overheating degradation. The feeding section (140-160℃) initially softens the POE particles, preventing bridging; the melting section (160-180℃) ensures complete melting of the POE, at which point the melt viscosity is 100-200 Pa·s, providing a flow basis for subsequent mixing; the homogenization section (170-190℃) slightly increases the temperature, which helps reduce the melt viscosity and promotes final uniform mixing. Specifically, the length-to-diameter ratio of the twin-screw extruder is 36-40:1.

[0061] A stepwise feeding method is adopted, with POE first melting to form a continuous phase, followed by the addition of the pre-dispersed system. This avoids the pre-dispersed system remaining in the high-temperature zone for too long, reducing MAH-g-POE degradation and graphene re-agglomeration due to high temperatures. Matching the feeding rates (POE 20~30 kg / h, pre-dispersed system 2~5 kg / h) ensures a stable proportion of the pre-dispersed system, preventing agglomeration caused by excessively high local concentrations. The control accuracy of the main feeder and side feeder is ±0.1 kg / h, and the feeding rate is linked and adjusted via a PLC system to ensure that the mass ratio fluctuation of POE to the pre-dispersed system is ≤0.3%. At screw speeds of 300-500 r / min, the high speed generates strong shear force, which can further peel off residual micro-agglomerates in the pre-dispersion system and uniformly disperse graphene into the POE melt. When the speed is <300 r / min, the shear force is insufficient, the mixing uniformity is poor, and graphene is prone to local enrichment; when the speed is >500 r / min, the shear heat generation is too high, which can easily lead to POE degradation.

[0062] Vacuum degree -0.08~-0.09MPa: can effectively remove volatiles from the system and effectively reduce bubbles.

[0063] Specifically, the die head temperature is 180~190℃, and the die opening diameter is 3~5mm.

[0064] (3) Granulation and shaping The elastomer strip is introduced into underwater pelletizing, with a pelletizing speed of 800~1200 r / min, a pellet diameter of 2~3 mm, a cooling water temperature of 20~30℃, and a cooling water pressure of 0.2~0.3 MPa. After pelletizing, the pellets are dried and sieved to obtain a graphene-reinforced POE elastomer composition.

[0065] In this invention, the pelletizing speed is matched with the extrusion rate to avoid stretching or accumulation of the extruded rubber strip; the cooling water temperature and pressure are controlled for rapid cooling and shaping, preventing pellet adhesion or deformation. The underwater pelletizer's cutter is made of cemented carbide (WC-Co alloy, Co content 8%~12%), and the gap between the cutter and the die head is controlled at 0.05~0.1mm to avoid strip tailing. After pelleting, the pellets are sent to a hot air dryer and dried at 80~100℃ for 10~15 minutes. The moisture content of the pellets (Kal Fischer method) is ≤0.5%.

[0066] In a preferred embodiment of the present invention, a mixing section and an exhaust section are further included sequentially between the melting section and the homogenizing section, wherein the temperature of the mixing section is 160~180°C and the temperature of the exhaust section is 160~180°C. The length percentages of each section are as follows: feeding section 20%, melting section 30%, mixing section 25%, venting section 15%, and homogenization section 10%.

[0067] In this invention, a mixing section and a venting section are added between the melting section and the homogenization section. The mixing section is equipped with 2-3 sets of reverse threaded elements. The reverse threads and forward threads create a "resistance difference": the forward threads push the melt forward, while the reverse threads impede the melt flow, forming a local high-pressure zone in the mixing section. The melt is repeatedly squeezed and sheared in this high-pressure zone, further tearing the graphene agglomerates (i.e., the tiny agglomerates remaining after pre-dispersion) into single layers or fewer layers. Simultaneously, MAH-g-POE can more fully coat the graphene surface, preventing secondary agglomeration. One set of reverse threads provides insufficient shear force; four or more sets will lead to excessively long melt residence time and excessively high local temperatures (potentially exceeding the POE degradation threshold of 230°C). Two to three sets can achieve a balance between "shear strength" and "temperature control."

[0068] The exhaust section is equipped with dual vacuum ports. The first vacuum port has a vacuum level of -0.07 to -0.08 MPa, and the second vacuum port has a vacuum level of -0.08 to -0.09 MPa. The first vacuum port removes a large amount of volatile components, such as residual octene monomers in POE and trace amounts of moisture in the pre-dispersion system. The low vacuum level prevents the melt from being excessively drawn towards the vacuum port, which could lead to blockage. The second vacuum port deeply removes residual trace amounts of non-volatile components, such as small amounts of decomposition products of antioxidants. The high vacuum level ensures complete devolatilization.

[0069] The 20% conveying section is used to transport the particles forward while preheating the POE elastomer particles to prepare for subsequent melting. The 20% length ensures a balance between conveying efficiency and preheating effect.

[0070] The 30% melting section is used to completely melt the POE particles, which requires sufficient temperature and residence time. The maximum 30% ratio can reduce the fluctuation of the mechanical properties of the finished product caused by local unmelted particles.

[0071] The 25% mixing section is used for strong shear mixing of molten POE and the pre-dispersed system added by side feeding, so that the pre-dispersed system and POE melt are dispersed for a second time. The 25% length can ensure sufficient shearing time and avoid graphene agglomeration.

[0072] The 15% venting section is used to remove small molecule volatiles from the melt. Since air bubbles in the melt can cause holes in the finished product, affecting tensile strength and thermal conductivity, the 15% length ensures that the volatiles can escape fully.

[0073] The homogenization section (10%) is used to homogenize the temperature and composition of the mixed melt to ensure consistent melt viscosity and prepare it for extrusion shaping.

[0074] In a preferred embodiment of the present invention, step (3) adopts a gradient heating mode for drying: first drying at 80°C for 5 minutes, and then heating to 100°C for 5-10 minutes.

[0075] In this invention, the first stage of drying at 80°C for 5 minutes gently removes surface free water, avoiding particle defects, and simultaneously reserving internal moisture diffusion channels for the second stage of deep dehydration. With no hardened shell on the surface, internal moisture can migrate smoothly to the surface. Then, the second stage of drying at 100°C for 5-10 minutes efficiently removes internal bound water, ensuring thorough drying. This helps eliminate microporous defects and ensures the stability of the product's mechanical and thermal conductivity properties.

[0076] In a preferred embodiment of the present invention, when hexagonal boron nitride is added in step (1), the ultrasonic oscillation frequency is adjusted to 30~35kHz, the stirring speed is adjusted to 2200~2500r / min, and the pre-dispersion time is extended to 20~25min.

[0077] In this invention, although hexagonal boron nitride (h-BN) and reduced graphene oxide (rGO) both belong to layered inorganic fillers, their interlayer bonding strength, sheet size, and surface properties differ significantly, which may lead to uneven dispersion and competition from agglomerates. The cavitation bubble rupture impact force generated by an ultrasonic frequency of 30~35kHz can effectively tear apart the interlayer bonds of h-BN, and the energy penetration depth reaches 8~10mm, which can act on the agglomerates of both rGO and h-BN simultaneously. A stirring speed of 2200~2500r / min can avoid h-BN sedimentation and competition with the agglomeration of the two fillers. A pre-dispersion time of 20~25min can ensure more complete exfoliation of h-BN and uniform distribution with the two fillers.

[0078] Furthermore, in order to ensure the dispersion effect of rGO and h-BN, the mass ratio of rGO to compatibilizer can be appropriately increased. When the mass ratio is 1:3, the compatibilizer can both cover the surface of rGO and counteract the adsorption effect of h-BN.

[0079] Example Example 1 A graphene-reinforced POE elastomer composition is provided, comprising the following raw materials in parts by weight: POE elastomer granules: 90 parts, using ExxonMobil 8780; Redox graphene: 3 parts, Shanghai Zhenzhun Biotechnology MS-21007, hydroxyl to carboxyl molar ratio of 3~5:1; Compatibilizer: Dow Fusabond N493, 6 parts; Antioxidant: Antioxidant 1010, 1.5 parts.

[0080] Graphene-reinforced POE elastomer compositions were prepared according to the following method: (1) Pre-dispersion treatment First, graphene oxide and compatibilizer are added to a high-speed mixing tank; Then, turn on ultrasonic oscillation at a frequency of 30kHz and a power of 400W, and simultaneously stir at a speed of 2000r / min for 15~30min, so that the graphene dispersion is ≥90%; Then, an antioxidant is added, and the mixture is stirred at a low speed of 650 r / min for 5 to 10 minutes, while controlling the system temperature to ≤50℃ during the stirring process, to obtain a graphene pre-dispersion system.

[0081] (2) Melt blending extrusion Using a twin-screw extruder, the barrel is sequentially configured according to the material flow direction: feed section 150℃, melting section 170℃, mixing section 170℃, venting section 170℃, and homogenization section 180℃. The lengths of each section are: feed section 20%, melting section 30%, mixing section 25%, venting section 15%, and homogenization section 10%. The mixing section is equipped with 3 sets of reverse screw elements, and the venting section is equipped with dual vacuum ports with vacuum levels set to -0.08MPa and -0.09MPa, respectively.

[0082] POE elastomer particles are added to the extruder through the main feed port at a rate of 20-30 kg / h. After the POE elastomer particles are completely melted, the graphene pre-dispersion system is added through the side feed port at a rate of 2-5 kg / h. After being sheared and mixed by a twin-screw extruder, the molten mixture is extruded from a die to form a continuous elastomer strip, wherein the die temperature is set to 185℃ and the die diameter is 4mm.

[0083] (3) Granulation and shaping The elastomer strip was introduced into an underwater pelletizer. The pelletizing speed was set to 1000 r / min, the pellet diameter to 2.5 mm, the cooling water temperature to 25°C, and the cooling water pressure to 0.25 MPa. After pelletizing, the pellets were sent to a hot air dryer and dried at 80°C for 5 min, then the temperature was raised to 100°C and dried for another 8 min. The moisture content of the pellets (Karl Fischer method) was ≤0.5%. After drying and sieving, a graphene-reinforced POE elastomer composition was obtained.

[0084] Example 2 The difference from Example 1 is that 4.5 parts of Dow Fusabond N493 and 1.5 parts of Dow AMPLIFY TY4817 were used as compatibilizers. Everything else is the same as in Example 1.

[0085] Example 3 The difference from Example 1 is that the compatibilizer is Dow Fusabond N493, 4.5 parts; Everything else is the same as in Example 1.

[0086] Example 4 The difference from Example 2 is that the antioxidant used is 0.9 parts of antioxidant 1010 and 0.6 parts of antioxidant 168; Everything else is the same as in Example 2.

[0087] Example 5 The difference from Example 1 is that 1.5 parts of antioxidant 168 were used; Everything else is the same as in Example 1.

[0088] Example 6 The difference from Example 2 is that the antioxidants used are antioxidant 1010 (0.75 parts) and antioxidant 168 (0.75 parts). Everything else is the same as in Example 2.

[0089] Example 7 The difference from Example 2 is that 1 part of antioxidant 1010 and 0.5 parts of antioxidant 168 are used; Everything else is the same as in Example 2.

[0090] Example 8 The difference from Example 2 is that 4 parts of Dow Fusabond N493 and 2 parts of Dow AMPLIFY TY4817 were used as compatibilizers. Everything else is the same as in Example 2.

[0091] Example 9 The difference from Example 2 is that 4.8 parts of Dow Fusabond N493 and 1.2 parts of Dow AMPLIFY TY4817 were used as compatibilizers. Everything else is the same as in Example 2.

[0092] Example 10 The difference from Example 1 is that 85 parts of POE elastomer particles, 1 part of reduced graphene oxide, 3 parts of compatibilizer, and 0.5 parts of antioxidant are used. Everything else is the same as in Example 1.

[0093] Example 11 The difference from Example 1 is that 95 parts of POE elastomer particles, 4 parts of reduced graphene oxide, 8 parts of compatibilizer, and 2 parts of antioxidant are used. Everything else is the same as in Example 1.

[0094] Example 12 The difference from Example 1 is that the redox graphene used is Shanghai Zhenzhun Biotechnology MS-30006; Everything else is the same as in Example 1.

[0095] Example 13 The difference from Example 1 is that in step (1), graphene oxide, compatibilizer and hexagonal boron nitride are added to the high-speed stirring tank; 2 parts of Defupeng PBN300 are used for hexagonal boron nitride and 9 parts of compatibilizer are used. Everything else is the same as in Example 1.

[0096] Example 14 The difference from Example 13 is that 6.75 parts of Dow Fusabond N493 and 2.25 parts of Dow AMPLIFYTY 4817 were used as compatibilizers. The rest is the same as in Example 13.

[0097] Comparative Example 1 The difference from Example 1 is that the POE elastomer particles used are Dow ENGAGE 8402, with a melt flow rate of 30 g / 10 min; Everything else is the same as in Example 1.

[0098] Comparative Example 2 The difference from Example 1 is that 1.5 parts of compatibilizer are used; Everything else is the same as in Example 1.

[0099] Performance testing 1. Mechanical property testing (1) Tensile strength and elongation at break Standard: According to GB / T 1410.3-2006, dumbbell-shaped specimen, tensile rate 50 mm / min.

[0100] (2) Compression permanent deformation rate Standard: Based on GB / T 7759.1-2015, conditions: 70℃×22h.

[0101] 2. Thermal conductivity test Thermal conductivity was tested using a laser flash thermal conductivity meter (LFA).

[0102] 3. Anti-aging performance test Tensile strength retention after aging: Xenon lamp aging test was conducted according to GB / T 16422.2-2022, with an irradiation intensity of 0.71 W / (m²). 2 (nm), aged for 1000h.

[0103] 4. Insulation performance test Volume resistivity: The test standard is based on GB / T 31838.2-2019, and the sample is a pressed sheet.

[0104] The test results of Examples 1-14 and Comparative Examples 1-2 are detailed in Table 1.

[0105] Table 1. Test results of Examples 1-14 and Comparative Examples 1-2 .

[0106] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, nor does it mean that the present invention must rely on the above process steps for implementation. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A graphene-reinforced POE elastomer composition characterized in that, The POE elastomer composition comprises the following raw materials by weight: POE elastomer particles: 85 to 95 parts, the melt flow rate of the POE elastomer particles is 5 to 20 g / 10 min, and the density is 0.87 to 0.89 g / cm 3 ; Redox graphene: 1-5 parts, the redox graphene has a flake diameter of 1-5 μm, a thickness of 1-5 nm, and a surface oxygen functional group content of 5-15 at%, and an ash content of ≤0.5%; Compatibilizer: 2-9 parts, the compatibilizer is maleic anhydride grafted POE, the maleic anhydride grafting rate of which is 0.5-2.0%, the melt flow rate is 10-30 g / 10 min, and the thermal decomposition temperature is ≥250°C; Antioxidant: 0.5-2 parts, the antioxidant is a hindered phenolic antioxidant and / or a phosphite antioxidant.

2. The POE elastomer composition of claim 1, wherein, The maleic anhydride grafted POE is a gradient grafting complex system, comprising high grafting MAH-g-POE with a grafting rate of 1.5-2.0% and low grafting MAH-g-POE with a grafting rate of 0.5-1.2% at a mass ratio of 2-4:

1.

3. The POE elastomer composition of claim 1, wherein, The POE elastomer particles are ethylene-octene copolymers, wherein the mass content of octene is 20-30%.

4. The POE elastomer composition of claim 1, wherein, The redox graphene is prepared by a modified Hummers method, and the molar ratio of hydroxyl groups to carboxyl groups in the redox graphene is 3-5:

1.

5. The POE elastomer composition of claim 1, wherein, The antioxidant is a complex of antioxidant 1010 and antioxidant 168 at a mass ratio of 1-2:

1.

6. The POE elastomer composition according to any one of claims 1 to 5, wherein Also included are 1-3 parts of hexagonal boron nitride with a flake diameter of 3-8 μm, a thickness of 3-8 nm, a purity of ≥ 99%, and a volume resistivity of ≥ 10 16 Ω-cm.

7. The method of preparing a graphene-reinforced POE elastomer composition according to any one of claims 1 to 6, wherein The preparation method comprises: (1) Pre-dispersion treatment First, add redox graphene, maleic anhydride grafted POE, and hexagonal boron nitride into a high-speed stirring tank; Then, start ultrasonic oscillation at a frequency of 20-40 kHz and a power of 300-500 W, and simultaneously stir at a speed of 1800-2500 r / min for 15-30 min, and the dispersion degree of graphene is ≥90%; Then, add an antioxidant and stir at a low speed of 500-800 r / min for 5-10 min to obtain a graphene pre-dispersion system; (2) Melt blending and extrusion Use a double-screw extruder, and the barrel comprises, in sequence according to the material flow direction, a feeding section at 140-160°C, a melting section at 160-180°C, and a homogenizing section at 170-190°C, the screw rotation speed is 300-500 r / min, and the vacuum degree is -0.08--0.09 MPa; Add POE elastomer particles into the extruder through the main feeding port at a rate of 20-30 kg / h, and after the POE elastomer particles are completely melted, add the graphene pre-dispersion system through the side feeding port at a rate of 2-5 kg / h; The melt mixture is extruded from the die to form a continuous elastomer strip after being sheared and mixed by the double screw; (3) Granulation and shaping Introduce the elastomer strip into underwater granulation, set the granulation rotation speed to 800-1200 r / min, the granulation diameter to 2-3 mm, the cooling water temperature to 20-30°C, and the cooling water pressure to 0.2-0.3 MPa, and obtain a graphene reinforced POE elastomer composition after drying and screening.

8. The preparation method according to claim 7, characterized in that, The melting section and the homogenizing section further comprise, in sequence, a mixing section and a degassing section, the temperature of the mixing section is 160-180°C, and the temperature of the degassing section is 160-180°C; The length ratio of each section is as follows: 20% for the feeding section, 30% for the melting section, 25% for the mixing section, 15% for the exhaust section, and 10% for the homogenizing section.

9. The preparation method according to claim 7, characterized in that, In step (3), the gradient temperature mode is used for drying: first drying at 80℃ for 5min, and then increasing the temperature to 100℃ for 5~10min.

10. The method of any one of claims 7 to 9, wherein the method further comprises the step of: In step (1), when the hexagonal boron nitride is added, the ultrasonic oscillation frequency is adjusted to 30~35kHz, the stirring speed is adjusted to 2200~2500r / min, and the pre-dispersion time is extended to 20~25min. ​