WO2021035202A1 - Graphene reinforced hybrid composites - Google Patents

Abstract

A graphene-reinforced hybrid polymeric composite is provided that includes a graphene filler and at least two polymer resins in which the graphene filler is intermixed. The graphene filler is a two-dimensional flake material with a thickness of from 0.34 nm to 50 nm and a diameter of from 0.1 micron to 50 microns. The graphene is dispersed or compounded into the at least two polymer resins at a high level of homogeneity. This can be achieved by either directly dispersing graphene filler into the final hybrid composite, or by making a master batch with at least one of the polymer resins in the first step and further dispersing the master batch into the final hybrid composites at certain let-down ratios in a second step. A process for dispersion of the graphene nanoplatelets in polymer resins is also provided.

Description

GRAPHENE REINFORCED HYBRID COMPOSITES

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority of United States Provisional Patent Application Serial No. 62/890,418 filed August 22, 2019, which is incorporated herein by reference.

FIELD OF INVENTION

[0002] The present invention relates in general to the field of graphene-reinforced polymeric composites and more particularly, to graphene-reinforced polyolefinic and elastomeric composites.

BACKGROUND OF THE INVENTION

[0003] Polymer composite reinforced with nanomaterial-based fillers are receiving more attentions in recent years as the composites can significantly improve the mechanical, thermal, or electric performance of the materials. For example, engineer plastics reinforced with nanomaterials can be used in automobiles to replace some of the parts that are traditionally made with relative heavy metals or polymer composites made with heavy fillers such as clay, silica, or calcium carbonate materials. This allows to reduce the weight of the automobiles and hence reduce the fuel consumption and carbon dioxide generation. Furthermore, improved polymer composites can also help extend the lives of numerous consumer and industrial products, thereby reducing the overall fossil resource consumption, recycling need, and landfill burdens.

[0004] One of the new classes of advanced nano fillers are graphene nano materials including graphene, graphene nanoplatelet (GnP), graphene oxide (GO), and reduced graphene oxide (rGO). Graphene, by definition, is a single layer of close-packed carbon atoms. The material has superior mechanical strength, excellent electrical and thermal conductivities, good barrier properties, and high surface area with a thin 2-dimensional morphology. Graphene nanoplatelets are multi-layer graphene sheets that retain many good properties of single-layer graphene but are much easier to produce and handle. Graphene oxide is an oxidized graphene with various oxygen-containing functionalities such as epoxide, carbonyl, carboxyl, and hydroxyl groups. Graphene oxide can be chemically or thermally reduced to form reduced graphene oxide. These graphene-based materials have received a lot of attentions in recent years for a variety of applications, including as fillers for polymer composite materials for performance enhancement in mechanical strength, light-weighting, chemical resistance, and thermal or electrical conductivities.

[0005] Like many nanomaterial-based composites, a critical factor in preparing graphene- based polymeric composites is an effective dispersion of the nano filler. There are several ways to prepare graphene-based polymer composites: (1) Solution processing in which graphene or graphene oxide is dispersed in a solvent and then mixed with a polymer solution by mechanical mixing or sonication. A composite can be obtained by vaporizing the solvent. This method has met with limited acceptance owing to the complexity of handling large volumes of solvent and inherent inefficiencies. This method is more often used for thermoset materials. (2) In-situ polymerization where graphene or graphene oxide is mixed with monomers or pre-polymers followed by polymerization. It is a very efficient method to uniformly disperse nano fillers and provide a strong interaction between the fillers and polymer matrix. In-situ polymerization, however, starts with monomers and is also not a low-cost process. (3) Melt Blending or melt intercalation where a thermoplastic polymer is mixed mechanically with graphene or graphene oxide at elevated temperatures using conventional methods like extrusion and injection molding. [0006] Melt blending is the most commonly used low-cost method for preparing commercial polymer composites with nano fillers. Melt blending is a high-temperature process requiring high-shear mixers or extruders and is done at temperatures above the melting point or the glass transition point of the polymer. Nevertheless, achieving desired dispersion by melt blending is a big challenge. Post-processing such as extruding, drawing, and injecting is frequently used to prepare well-dispersed composite master batches, fibers, or parts. During this process, the introduction of graphene into the system is critical in determining the outcome of the final composite products. Melt blending is a method well suited for mass production, but very often the simple mixing does not result in effective dispersion. The uneven distribution of graphene particles in the polymer matrices, especially when the graphene is agglomerated, may cause stress concentration in certain places, thereby imparting, or even reducing the mechanical properties of the composite. This is a practical issue in polymer processing. First, graphene- based materials are light and sometimes fluffy. Conventional methods to pre-blend graphene and polymer powders before the melt blending or extrusion tend to be less effective in dispersing graphene, especially when the graphene loading in the composite is low. Second, it is often more difficult to disperse graphene into certain polymer resins than in others. For example, melt or glass transition temperature and viscosity are important in polymer compounding. The melting temperature plays an important role in creating a good flow in a blend. Material with high melt flow index (low viscosity) could be used as a carrier for graphene-based fillers for effective dispersion in a material with a low melt flow index (high viscosity).

[0007] US 10,329,391 provides a graphene-reinforced polymer matrix composite prepared by polymer processing methods comprising in situ exfoliation of well-crystallized graphite particles dispersed in a molten thermoplastic polymer matrix. Extrusion of a graphite-polymer mixture shears the graphite to exfoliate graphene sheets and improves the mechanical properties of the bulk polymer. The graphene-reinforced polymer matrix is prepared by (a) distributing graphite microparticles into a molten thermoplastic polymer phase comprising one or more matrix polymers; and (b) applying a succession of shear strain events to the molten polymer phase so that the matrix polymers exfoliate the graphite successively with each event until at least 50% of the graphite is exfoliated to form a distribution in the molten polymer phase of single- and multi-layer graphene nanoparticles less than 50 nanometers thick along a c-axis direction. Since the process starts with graphite particles and carries out exfoliation during the mechanical shearing or extrusion process, the extent of the exfoliation, the quality of graphene sheets such as particle size and thickness, and distribution of the graphene sheets in the composites cannot be well controlled, especially when the loading of graphene has to be low. Therefore, the application suggests a graphene-reinforced polymer matrix composite comprising an essentially uniform distribution in a thermoplastic polymer of about 10% to about 50% of the total composite weight. However, with well-exfoliated graphene, especially those with high surface area, it is hard to load graphene in a polymer matrix at higher than 10% while still maintaining good mechanical properties.

[0008] US Patent Application Publication US2018/0272565 provides a method of producing pellets of a graphene-polymer composite by (a) mixing multiple particles of a graphitic material and multiple particles of a solid polymer carrier material to form a mixture in an impacting chamber; (b) operating the energy impacting apparatus to peel off graphene sheets from the graphitic material particles and produce graphene-coated polymer particles inside the impacting chamber; and (c) feeding multiple graphene-coated polymer particles into an extruder to produce filament or pallet composite products. Here again, it is difficult to control the extent and quality of the in-situ exfoliated graphene. Furthermore, it is challenging to have a good coating when the graphene loading needs to be low in terms of total weight percentage. More importantly, a potential problem with such an approach is that completely coated polymer has poor subsequent processability due to poor interactions and bonding between graphene on the polymer particle surface.

[0009] US9,790,334 disclosed a technology relating to polymer-graphene nanocomposites and methods for producing polymer-graphene nanocomposites using master batches of graphene and a polymer or polymer precursor. In this approach, the master batch is prepared by mixing a slurry of graphene in one or more solvent with a polymer, followed by solvent removal, to obtain a master batch at a graphene loading of 20-60 wt%. The extra wet steps of slurry preparation and solvent removal are not ideal for low-cost mass production of polymer composites.

[0010] Thus, there exists a need for a polymeric composite in which graphene is dispersed to a high level of homogeneity in at least two miscible polymer resins.

SUMMARY OF INVENTION

[0011] A composite is provided with graphene dispersed or compounded into at least two polymer resins at a high level of homogeneity. This can be achieved by either directly dispersing graphene filler into the final hybrid composite, or by making a master batch with at least one of the polymer resins in the first step and further dispersing the master batch into the final hybrid composites at certain let-down ratios in a second step. A process for dispersion of the graphene nanoplatelets in polymer resins is also provided. According to embodiments, a graphene-reinforced hybrid polymeric composite is provided that includes a graphene filler and at least two polymer resins in which the graphene filler is intermixed. The graphene filler is a two-dimensional flake material with a thickness of from 0.34 nm to 50 nm and a diameter of from 0.1 micron to 50 microns. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Examples illustrative of embodiments are described below with reference to figures attached hereto. In the figures, identical structures, elements or parts that appear in more than one figure are generally labeled with a same numeral in all the figures in which they appear. Dimensions of components and features shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily shown to scale. The figures are listed below.

[0013] FIG. 1 shows a flow chart of preparing graphene-based hybrid composites where graphene is fist dispersed into a polymer resin A to form a master batch and then further dispersed into a second polymer resin B to form a binary hybrid composite at a certain let down ratio.

[0014] FIG. 2 shows a flow chart of a way of preparing graphene-based hybrid composites where graphene is fist dispersed into a polymer resin to form a master batch and then further dispersed into at least two another polymer resins B and C to form a ternary or higher hybrid composite at a certain let-down ratio.

[0015] FIG. 3 shows a flow chart of a way of preparing graphene-based hybrid composites where graphene is directly dispersed into a mixture of at least two polymer resins to form a master batch followed by then further dispersing into at least one of the polymer resins to form a binary hybrid composite at a certain let-down ratio.

[0016] FIG. 4 shows a flow chart of a way to prepare graphene-based hybrid composites where graphene is directly dispersed into a mixture of at least two polymer resins to form a master batch and then further dispersed into at least one another polymer resin to form a ternary hybrid composite at a certain let-down ratio.

[0017] FIG. 5 shows a flow chart of a way to prepare graphene-based hybrid composites where graphene is directly dispersed into a mixture of three polymer resins to form a master batch, followed by further dispersed into one of the polymer resins used to make the master batch to form a hybrid composite at a certain let-down ratio.

[0018] FIG. 6 shows a flow chart of a way to prepare graphene-based hybrid composites where graphene is directly dispersed into a mixture of two polymer resins to form one master batch graphene is dispersed into one polymer resin to form another master batch and then then further mixed to form a ternary hybrid composite at a certain let-down ratio.

[0019] FIGS. 7A-7D show the performance enhancement of a Graphene-reinforced Polyamide 6 (PA6)/High Density Polyethylene (HDPE) hybrid composite.

[0020] FIG. 8 shows a Graphene-reinforced Polyether block amide (PEBA) composite.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0021] The present invention has utility as a composite amenable to conventional processing to yield articles with superior properties relative to like articles absent the inventive graphene dispersion. Graphene nanoplatelets are dispersed or compounded into at least two polymer resins by either directly dispersing graphene filler into the final hybrid composite, or by making a master batch with at least one of the polymer resins in the first step and further dispersing the master batch into the final hybrid composites at certain let-down ratios in a second step.

[0022] The present invention has been designed to overcome the deficiencies in the prior arts noted above and provides ease of subsequent processing and improved properties relative to conventional articles devoid of graphene, as well as through graphene dispersion by the aforementioned prior art techniques. Through a process of melt blending, an inventive graphene dispersion is obtained.

[0023] The present invention of graphene-based hybrid composites affords at least two benefits for such hybrid polymer composites: (1) At least one of said polymer resins can serve as a carrier in a master batch for the eventual uniform dispersion of graphene in the hybrid final composite. (2) Blending of different polymer resins may have some synergistic effect in improving or modifying mechanical, chemical, thermal, or electric properties of the final composite.

[0024] The graphene-based fillers illustratively include graphene, few-layer graphene (FLG), graphene nanoplatelet, graphene oxide (GO), and reduced graphene oxide (rGO). The polymer resins include thermoplastics and elastomers. Specific resins illustratively include polypropylene, polyamide, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, thermoplastic copolyester, polybutyleneterapthalates, polythalamides polycarbonate, polyether ether ketone, acrylonitrile butadiene styrene, nature and synthetic rubbers, thermoplastic polyurethane, polyether block amide, polystyrenes, polyphenylene sulfides, and polyacrylonitrile.

[0025] It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.

[0026] As used herein, weight percent (wt. %) is defined as the percent of the weight of a species in a mixture or composition.

[0027] The following description of various embodiments of the invention is not intended to limit the invention to these specific embodiments, but rather to enable any person skilled in the art to make and use this invention through exemplary aspects thereof.

[0028] All publications, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety.

[0029] Unless indicated otherwise, explicitly or by context, the following terms are used herein as set forth below. [0030] As used in the description of the invention and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0031] Also, as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”).

[0032] As used herein, graphene is defined as a two-dimensional material constructed by close-packed carbon atoms including a single-layer graphene, double-layer graphene, multi layer graphene, and graphene nanoplatelets.

[0033] As used herein double-layer graphene is defined as a stack graphene of two layers, multi-layer graphene is defined as a stack of graphene of 3-10 layers, graphene nanoplatelet is defined as a stack of graphene of more than 10 layers. The graphene materials can be made by chemical or mechanical exfoliation of graphite, chemical vapor deposition, physical vapor deposition, and epitaxy growth on a substrate.

[0034] As used herein, graphene oxide is defined as graphene with various oxygen- containing functionalities such as epoxide, carbonyl, carboxyl, and hydroxyl groups and a total oxygen content of 10-60wt%, typically around 50wt%.

[0035] As used herein, reduced graphene oxide is defined as graphene oxide that has been chemically or thermally reduced with a total oxygen content of typically in the range of 10%- 50% depending on the extent of the reduction.

[0036] As used herein, a nanoplatelet is defined as having planar dimensional in orthogonal direction of each independently between 2 and 20 nanometers.

[0037] In one embodiment, referring to FIG. 1, graphene filler (1) is fist dispersed into a polymer resin A (2) by melt blending to form a master batch (10) wherein the master batch is then further dispersed by melt blending into a second polymer resin B (3) to form the hybrid composite (20) at a certain let-down ratio (LDR) (FIG.l). As used herein, the let-down ratio is defined as the weight ratio between a virgin polymer and a masterbatch. Typical let-down ratio is in the range of 1: 1 to 20: 1.

[0038] In another embodiment, graphene filler (1) is first dispersed into a polymer resin A (2) by melt blending to form a master batch (10) wherein the master batch is then further blended into at least another two polymer resins B (3) and C (4) by melt blending to form the hybrid composite (20) at a certain let-down ratio (FIG..2).

[0039] In yet another embodiment, graphene filler (l)is directly dispersed into a mixture of at least two polymer resins A (2) and B (3) by melt blending to form a master batch (10) wherein the master batch is then further dispersed into at least one of the polymer resins A (2) or B (3) by melt blending to form the hybrid composite (20) at a certain let-down ratio (FIG. 3).

[0040] In yet another embodiment, graphene filler (1) is directly dispersed into a mixture of at least two polymer resins A (2) and B (3) by melt blending to form a master batch (10). The master batch is then further dispersed into at least one of another polymer resins C (4) by melt blending to form the hybrid composite (20) at a certain let-down ratio (FIG. 4).

[0041] In yet another embodiment graphene filler (1) is directly dispersed into a mixture of three polymer resins A (2), B, (3) and C (4) to form a master batch (10). The master batch is then further dispersed into at least one of the polymer resins used to make the master batch (10), A (2), B, (3) or C (4), to form a hybrid composite (20) at a certain let-down ratio (FIG. 5).

[0042] In yet another embodiment graphene filler (1) is directly dispersed into a mixture of two polymer resins A (2) and B (3) to form one master batch (10). Graphene filler (1) is dispersed into another polymer resin C (4) to form another master batch (11). The master batches (10 and 11) are then further mixed to form a ternary hybrid composite (20) at a certain let-down ratio (FIG. 6). [0043] In yet another embodiment, graphene is directly dispersed into a mixture of at least two polymer resins by melt blending to form a graphene-reinforced hybrid composite with or without a master batch step.

[0044] In some embodiments, one of more other additives might be used including one or more compatibilizer. Compatibilization in polymer chemistry is the addition of a substance to an immiscible blend of polymers and other chemicals that will increase their interaction or stability. Polymer blends are typically described by coarse, unstable phase morphologies. This results in poor mechanical properties. Compatibilizing the system will make a more stable and better blended phase morphology by creating interactions between the two previously immiscible polymers. Not only does this enhance the mechanical properties of the blend, but it often yields properties that are generally not attainable in either single pure component. Other additives may also be added to perform certain functionalities including barrier, anti-oxidation, anti-corrosion, flame retardant, lubrication, dyeing, and plasticization (Chen, C., & White, J. (1993). Compatibilizing Agents in Polymer Blends: Interfacial Tension, Phase Morphology, and Mechanical Properties. Polymer Science and Engineering, 33(14), 923-930).

Direct compounding

[0045] In the direct dispersion embodiments of the present invention, depending on the application, the graphene content in the hybrid composite is in the range of 0.001 wt% - 50 wt%. In some inventive embodiments, the graphene content in the hybrid composite is in the range of 0.001 wt% - 20 wt%. In yet another inventive embodiment, the graphene content in the hybrid composite is in the range of 0.001 wt% - 10 wt%. In yet another inventive embodiment, the graphene content in the hybrid composite is in the range of 0.001 wt% - 5 wt%. In yet another inventive embodiment, the graphene content in the hybrid composite is in the range of 0.001 wt% - 2.5 wt%. [0046] In a multiple-polymer resin composite, the ratio between said polymer resins is adjusted depending on application need. For example and for illustration purpose, in a binary hybrid composite which contains polymer A and polymer B, the ratio of polymer A to polymer B is in the range of 0.1 : 99.9 to 99.9 : 0.1 by weight. In a preferred embodiment, the ratio of polymer A to polymer B is in the range of 1 : 99 to 99 : 1 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 5 : 95 to 95 : 5 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 10 : 90 to 90 : 10 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 20 : 80 to 80 : 20 by weight.

[0047] Melt or glass transition temperature is important in polymer compounding. The melting temperature plays an important role in creating a good flow in a blend. In an exemplary embodiment, HDPE/PA6/graphene blend was processed at a temperature in the range of 230°C - 260°C, which was high enough to melt PA6 but still not too high to degrade HDPE.

[0048] Viscosity is also important for the melt compounding. Material with high melt flow index (low viscosity) could be used as a carrier for graphene fillers for effective dispersion in a material with a low melt flow index (high viscosity).

Master batch approach

[0049] In the master batch inventive embodiments, graphene nanoplatelet filler can be dispersed into at least one polymer resin. The master batch can contain graphene nanoplatelet filler at a concentration from 1 wt% - 50 wt%. In some inventive embodiments, the graphene content is in the range of 1 wt% - 20 wt%. In yet another inventive embodiment, the graphene content is in the range of 5 wt% - 10 wt%.

[0050] In the master batch inventive embodiments, when graphene nanoplatelet filler is dispersed into at least two polymer resins, the ratio between said polymer resins is adjusted depending on application need. For example, in a binary master batch composed of two polymer resin, the ratio of polymer A to polymer B is in the range of 0.1 : 99.9 to 99.9 : 0.1 by weight. In some inventive embodiments, the ratio of polymer A to polymer B is in the range of 1 : 99 to 99 : 1 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 5 : 95 to 95 : 5 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 10 : 90 to 90 : 10 by weight. In yet another inventive embodiment, the ratio of polymer A to polymer B is in the range of 20 : 80 to 80 : 20 by weight. The master batch can contain graphene nanoplatelet filler at a concentration from 1 wt% - 50 wt%. In some inventive embodiments, the graphene content is in the range of 1 wt% - 20 wt%. In yet another inventive embodiment, the graphene content is in the range of 5 wt% - 10 wt%.

[0051] In the master batch embodiments, final hybrid composites are prepared by further dispersing the master batch in at least one polymer resin at a preselected let-down ratio. In the final multiple-polymer hybrid composite, the ratio between said polymer resins is adjusted depending on application need. For example, in a binary hybrid composite which contains polymer A and polymer B, the ratio of polymer A to polymer B is in the range of 0.1 : 99.9 to 99.9 : 0.1 by weight. In some inventive embodiments, the ratio of polymer A to polymer B is in the range of 1 : 99 to 99 : 1 by weight. In yet another inventive embodiments, the ratio of polymer A to polymer B is in the range of 5 : 95 to 95 : 5 by weight. In yet another inventive embodiments, the ratio of polymer A to polymer B is in the range of 10 : 90 to 90 : 10 by weight. In yet another inventive embodiments, the ratio of polymer A to polymer B is in the range of 20 : 80 to 80 : 20 by weight.

[0052] In some inventive embodiments, the hybrid composite product can be in the one of the forms: a powder, a pellet, a fiber, a yam, a fabric, a film, a sheet, or a direct structural part. As used herein, powders are dry particles produced by the grinding, crushing, or disintegration of a solid substance with a particle size in the range from several nanometers to several millimeters. Pellets are small particles typically created by compressing an original material with a particle size in the range from several microns to several centimeters. Fibers are one dimensional substances that are significantly longer in their length than in their width with a diameter typically from several microns to several millimeters. Yam is a long continuous length of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, or ropemaking. Fabrics are textile materials made through weaving, knitting, spreading, crocheting, or bonding of fibers or yams that may be used in production of further goods such as clothes. Films are a thin continuous polymeric material with a thickness typically in the range of several microns to hundreds of microns. Sheets are thick continuous polymeric material with a thickness typically in the range of several microns to several millimeters.

EXEMPLARY EMBODIMENTS

Example 1: Graphene-reinforced Polyamide 6 (PA6)/High Density Polyethylene (HDPE) hybrid composites

[0053] Melt blending was utilized to disperse graphene nanoplatelets into different resin systems. First, they were dispersed into HDPE to form graphene-reinforced HDPE masterbatch. Second, they were dispersed into a mixture of HDPE with a thermoplastic compatibilizer system (TCS) to form graphene-reinforced HDPE+TCS masterbatch (referred to as masterbatch 1). Third, they were dispersed into PA6 to form graphene reinforced PA6 masterbatch (referred to as masterbatch 2). To study the effects of graphene nanoplatelet on the physical properties of HDPE, HDPE masterbatch was melt-blended with HDPE to create HDPE composites at certain LDRs [%], i.e., 2.5 LDR [%], 5 LDR [%], 10 LDR [%], and 25 LDR [%]. Additionally, masterbatches 1 and 2 were mixed at two different ratios (i.e., ratios I and II) to form hybrid masterbatches I and II. Each hybrid masterbatch was melt-blended with HDPE to create hybrid composites at certain LDRs [%], i.e., 2.5 LDR [%], 5 LDR [%], 10 LDR [%], and 25 LDR [%].

[0054] The pristine HDPE, HDPE and hybrid composites were characterized to understand the effects of graphene nanoplatelets on the tensile and flexural properties. Based on the data collected through mechanical testing, the elastic and flexural properties of HDPE hybrid composites outperform those of HDPE composites, as shown in FIGS. 7A-7D. The data show an increasing trend in properties with respect to graphene nanoplatelet final LDR [%], yielding a maximum increase at 25 LDR [%].

Example 2: Graphene-reinforced Polyether block amide (PEBA) composites [0055] Melt blending was utilized to disperse graphene nanoplatelets into a mixture of PEBA with a TCS to form PEB A+TCS masterbatch (referred to as masterbatch 1). Masterbatch 1 was then melt-blended with PEBA to form a ternary matrix, resulting in PEBA hybrid composites at certain LDRs [%], i.e., 2.5 LDR [%], 10 LDR [%], 24 LDR [%], and 50 LDR [%]·

[0056] The pristine PEBA, PEBA+TCS, and PEBA hybrid composites were characterized to understand the effects of graphene nanoplatelets on retention of modulus at a certain deformation through strain-recovery cycle tests. Based on the data collected, the percent retention of modulus for the PEBA hybrid composites at 2.5 LDR [%] and 10 LDR [%] outperforms that of pristine and PEBA+TCS composites through 9 consecutive cycles, yielding a maximum retention at 10 LDR [%], as shown in FIG. 8.

Claims

1. A graphene-reinforced hybrid polymeric composite comprising: a graphene filler being a two-dimensional flake material with a thickness of from 0.34 nm to 50 nm and a diameter of from 0.1 micron to 50 microns; and at least two polymer resins in which said graphene filler is intermixed.

2. The graphene-reinforced hybrid polymer composite of claim 1 wherein the graphene filler is one or more of: single-layer graphene, double layer graphene, multi-layer graphene, graphene nanoplatelet, graphene oxide, and reduced graphene oxide, and a combination thereof.

3. The graphene-reinforced hybrid polymer composite of claim 1 wherein said graphene filler is present from 0.001 wt% to 50 wt%.

4. The graphene-reinforced hybrid polymer composite of claim 1 wherein said graphene filler is present from 0.001% to 10 wt%.

5. The graphene-reinforced hybrid polymer composite of claim 1 wherein said graphene filler is present from 0.001% to 5 wt%.

6. The graphene-reinforced hybrid polymer composite of claim 1 wherein the at least two polymers are two or more of: polypropylene, polyamide, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, polycarbonate, polyether ether ketone, acrylonitrile butadiene styrene, nature and synthetic rubbers, thermoplastic polyurethane, polystyrenes, polyether block amide, polyphenylene sulfides, polyacrylonitriles, and combinations thereof.

7. The graphene-reinforced hybrid polymer composite of claim 3 wherein the at least two polymer are present from 50 wt% to 99.999 wt%.

8. The graphene-reinforced hybrid polymer composite of claim 7 wherein each of the at least two polymer resins is present from 0.1 wt% to 99.9 wt%.

9. The graphene-reinforced hybrid polymeric composite of claim 1 further comprising additives of a compatibilizer, a barrier, an anti-oxidant, an anti-corrosion agent, a flame retardant, a lubricant, a dye, a pigment, and a plasticizer.

10. A graphene-reinforced hybrid polymeric composite in claim 1 wherein the composite is made by melt blending through direct compounding into the final said hybrid composite without a master batch step.

11. The graphene-reinforced hybrid polymeric composite in claim 1 wherein the composite is in the form of a powder, a pellet of powder, a fiber, a yam, a fabric, a film, a sheet and a structural part.

12. A graphene-reinforced hybrid polymeric composite comprised of a graphene filler and at least two polymer resins wherein the graphene filler being a two-dimensional flake material with a thickness in the range of 0.34 nm to 50 nm and a diameter in the range of 0.1 micron to 50 microns, the polymer resins include thermoplastics and elastomers, and the composite is made by melt blending through preparing a master batch in the first step followed by further compounding to the final hybrid composite in a certain let-down ratio by melt-blending.

13. The graphene-reinforced hybrid polymer composite in claim 12 wherein the graphene filler comprises at least one of single-layer graphene, double-layer graphene, multi-layer graphene, graphene nanoplatelet, graphene oxide, or reduced graphene oxide.

14. The graphene-reinforced hybrid polymer composite in claim 13 wherein the content of said graphene filler in the master batch is in the range of 1% - 20 wt%.

15. The graphene-reinforced hybrid polymer composite in claim 13 wherein the content of said graphene filler in the master batch is in the range of 5% - 10 wt%.

16. The graphene-reinforced hybrid polymer composite in claim 12 wherein the polymer- resins comprises at least one of: polypropylene, polyamide, high density polyethylene, low density polyethylene, linear low density polyethylene, polyethylene terephthalate, polycarbonate, polyether ether ketone, acrylonitrile butadiene styrene, nature and synthetic rubbers, thermoplastic polyurethane, polystyrenes, polyether block amide, polyphenylene sulfides, or polyacrylonitriles.

17. The graphene-reinforced hybrid polymer composite in claim 16 wherein the content of any of the polymer resins is in the range of 0.1 wt% to 99.9 wt%.

18. The graphene-reinforced hybrid polymer composite in claim 13 wherein the content of said graphene filler in the final composite is in the range of 0.001 wt% - 50 wt%.

19. The graphene-reinforced hybrid polymer composite in claim 13 wherein the content of said graphene filler in the composite is in the range of 0.1 wt% - 10 wt%.

20. The graphene-reinforced hybrid polymer composite in claim 13 wherein the content of said graphene filler in the composite is in the range of 0.5 wt% - 5 wt%.