Graphene oxide-reinforced polyamide 6 / high-density polyethylene blend nanocomposite and preparation method thereof

Abstract

The invention relates to a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite and a preparation method thereof. With the invention, a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend nanocomposite with maximized levels of homogeneity level is introduced. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing used in the production of graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. In the invention, all the problems encountered in incorporating GO (graphene oxide) content into polymer nanocomposites containing polyamide 6 (PA6) and high-density polyethylene (HOPE) are eliminated and a nanocomposite is introduced in which the enhancing properties of GO are effectively transferred to the nanocomposite structure. In addition, the invention eliminates the limitations of the polyamide 6 / high-density polyethylene (PA6 / HDPE) blend nanocomposite, such as unstable phase morphologies and low interface strength.

Description

[0001] GRAPHENE OXIDE-REINFORCED POLYAMIDE 6 / HIGH-DENSITY POLYETHYLENE BLEND NANOCOMPOSITE AND PREPARATION METHOD THEREOF

[0002] Technical Field of the Invention

[0003] The invention relates to a graphene oxide-reinforced polyamide 6 / high-density polyethylene (PA6 / HDPE) blend nanocomposite and a preparation method thereof.

[0004] State of the Art

[0005] Polymers are large molecular structures that find a wide range of applications from daily life to advanced technology and are considered the building blocks of the modern world. Polymers, which are used in many fields from plastics to fibers, adhesives to coatings, offer significant advantages over traditional materials such as metals, ceramics, and glass thanks to their properties such as lightness, flexibility, strength, and chemical resistance. This versatile use of polymers makes them indispensable materials for modern life. This versatile use of polymer materials leads to an increase in attempts to discover new application areas day by day.

[0006] Among the polymers, polyamide 6 (PA6) stands out thanks to its low manufacturing cost, high melting temperature, good resistance to corrosion and chemicals, high strength, easy processability, and processing properties. In addition, the main advantages of PA6, a tribo material, are that it exhibits good abrasion resistance and does not require lubrication under many conditions. High-density polyethylene (HDPE), another important polymer, stands out as a good bearing material due to its low-cost structure, high resistance to moisture, and low friction coefficients. In addition to these properties, PA6 and HDPE are commercially important polymers that are used in millions of tons every year. Developing and changing engineering problems have made it necessary to improve the mechanical, thermomechanical, and tribological properties of these materials.

[0007] In the state of the art, when PA6 and HDPE polymers are used together, the bond between the two phases remains weak and therefore the interface strength is very low. This situation causes unbalanced phase morphologies to form throughout the blend, making it difficult to obtain a homogeneous structure. Furthermore, poor interface strength increases the tendency for segregation between PA6 and HDPE phases, leading to weakening of mechanical properties and severe performance losses, especially in properties such as impact and tensile strength. These limitations limit the use of PA6 / HDPE blends in applications that require strength and longevity.

[0008] In the present art, many methods have been introduced to improve the properties of said polyamide 6 (PA6) polymer and high-density polyethylene (HDPE). One of the most important of said methods is the polymer blending method. Polymer blending is the process of homogenizing two or more polymers using specialized methods where homopolymers or copolymers with structural differences are insufficient on their own. The product obtained after the polymer blending process is a polymer blend. The properties of polymer blends are influenced by the compatibilizer additives used to enhance the phase distribution and interfacial interaction between phases. PA6 and HDPE blends use the basic properties of PA6 and HDPE, while eliminating their main disadvantages. With a PA6 and HDPE blend, it is possible to achieve a new combination by adjusting the properties specific to both polymers within acceptable limits.

[0009] In the state of the art, graphene oxide (GO) is often preferred as an additive to improve the properties of polyamide 6 (PA6) and high-density polyethylene (HDPE) polymers. GO has outstanding mechanical properties such as high strength and hardness. Among the reasons why graphene oxide is preferred in polymers are that it increases mechanical strength, improves thermal stability, enhances gas barrier properties, provides electrical and thermal conductivity, increases abrasion and friction resistance, provides fire resistance, offers biocompatibility, and has antimicrobial properties. As a result, in the state of the art, the use of graphene oxide in structures containing polyamide 6 (PA6) and high-density polyethylene (HDPE) stands out as one of the effective methods used to improve polymer properties.

[0010] In nanocomposites produced by direct melt mixing method, which is another method introduced to improve the properties of polyamide 6 (PA6) polymer and high-density polyethylene (HDPE) mentioned in the present technique, graphene oxide (GO), which is desired to be reinforced into the polymer and considered as a crucial material in improving the properties of polymer nanocomposites, tends to agglomerate as a result of the inability to obtain a homogeneous distribution and this situation negatively affects the mechanical performance of the nanocomposite. In the additions of GO to nanocomposite structures consisting of polyamide 6 (PA6) and high-density polyethylene (HDPE), inhomogeneous dispersion and agglomeration prevent the effective transfer of the superior mechanical properties of GO to the matrix.

[0011] In the state of the art, where the interaction of PA6 / HDPE and GO is insufficient, the free movement of the polymer chains within the crystal structure cannot be restricted, leading to the nanocomposite material maintaining its crystallinity. Failure to reduce crystallinity negatively affects the effective bonding and dispersion of GO with the polymer matrix, reducing the mechanical performance of the nanocomposite. This limitation results in the PAS and HDPE chains remaining in a tight crystalline structure, resulting in the failure to achieve the expected improvements in properties such as strength and flexibility of the nanocomposite.

[0012] In the present art, due to the limited effect of GO, the expected improvement in the degradation temperature (Td) and thermal stability of polymer nanocomposites containing PAS and HDPE cannot be achieved. This limitation leads to the inability of the nanocomposite to offer sufficient thermal performance in areas of use at high temperatures. Only a slight increase in thermal stability despite the reinforcement of GO prevents obtaining nanocomposite materials that are more resistant to degradation at high temperatures, which limits the use of the nanocomposite in applications requiring long-term thermal strength.

[0013] In the state of the art, GO cannot be incorporated into polymer nanocomposites containing PA6 and HDPE in the desired dimensions due to reasons such as agglomeration and homogeneous distribution problems, processability and viscosity increase, and structural compatibility problems. If the GO weight ratio cannot be increased sufficiently, the tensile and flexural strength of PA6 / HDPE+GO nanocomposites is unable to show the expected improvement compared to the PA6 / HDPE blend. This limitation leads to the nanocomposite's inability to offer adequate performance in applications requiring mechanical strength. Inadequate additive amount of GO prevents the increase of tensile and flexural strength, reduces the load carrying capacity of the material, and shortens its service life. In the present art, despite the addition of GO, the expected improvement in the storage modulus cannot be achieved and the rigidity of the nanocomposite cannot be increased to the desired level. The insufficient reinforcement of GO prevents the PA6 / HDPE nanocomposite from offering the required mechanical strength in all temperature ranges, keeping the storage modulus of the nanocomposite at low levels. This limitation limits the dimensional stability and load carrying capacity of the nanocomposite, especially under high temperature conditions, and reduces the performance of the nanocomposite in applications where more rigid and durable materials are needed. In the present art, the inability to homogeneously distribute GO in the nanocomposite matrix prevents the decrease of the tan delta value. This reduces the performance of the nanocomposite in applications that require hardness and strength, leading to significant limitations in terms of dimensional stability and mechanical strength in the long term. In the present art, GO not being sufficiently homogeneously dispersed and integrated in the polymer matrix results in failure to achieve the effect of raising the glass transition temperature (Tg). This shortcoming negatively affects the thermal stability of the material by reducing its stability at high temperatures. Since sufficient Tg increase is not achieved, it becomes difficult for the nanocomposite to resist deformation and loss of performance under high temperature conditions. As a result, in the present art, GO is not effectively integrated into the polymer matrix, limiting the thermal performance of the material and preventing its use in high-temperature resistant applications.

[0014] In the present art, the addition of GO to PA6 / HDPE nanocomposites does not reduce the friction coefficient as desired. Inadequate dispersion or incompatibility of GO prevents the reduction of frictional resistances, restricting the nanocomposite from showing efficient performance. When the reduction in the coefficient of friction is not achieved, the wear resistance of nanocomposites decreases, which can limit the efficiency of the material in applications that require long-lasting use and high performance. This situation creates an inadequacy to meet the need for friction-resistant materials, especially in moving parts.

[0015] In the state of the art, the inability to reduce the friction coefficient due to GO not being sufficiently effective in the nanocomposite leads to an increase in the temperatures generated during friction, which negatively affects the thermal strength. Increased temperature during friction can cause temperature-induced deterioration in long-term use of the nanocomposite and weaken the structural integrity of the nanocomposite. Failure to achieve a low coefficient of friction reduces the wear resistance of the material, limits its thermal strength and shortens its service life in applications requiring high performance.

[0016] In the present art, PA6 / HDPE+GO nanocomposites cannot provide the expected protection against wear due to the inability to form a sufficiently stable transfer film on steel surfaces. Failure to ensure stability in the transfer film leads to the inability of the nanocomposite material to offer effective protection on friction surfaces and increases material loss. This limits the long-term strength of the nanocomposite, especially in high wear resistant applications, and causes performance losses due to surface wear.

[0017] In the state of the art, it is observed that the rigid structure of the GO does not sufficiently increase the hardness and loadcarrying capacity of the nanocomposite. This shortcoming causes the nanocomposite to be insufficient to reduce the wear rate, limiting the longevity and durability of the material. The inability to fully achieve the effect of GO makes it difficult to use the nanocomposite effectively in high-performance and wearresistant applications and jeopardizes the continuity of performance.

[0018] In order to eliminate all these limitations in the present art, it is necessary to introduce a nanocomposite and the preparation method thereof, in which all the problems encountered in the incorporation of GO (graphene oxide) content in polymer nanocomposites containing PA6 and HOPE are eliminated and the enhancing properties of GO are effectively transferred to the nanocomposite structure.

[0019] Description of the drawings

[0020] Fig. 1. DSC heating thermograms of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0021] Fig. 2. TGA thermograms of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites. Fig. 3. Comparative graph showing the maximum tensile strength (MPa) of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer composites, wherein; F is maximum tensile strength and G is Elasticity modulus, A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0022] Fig. 4. Graph showing the comparative flexural strength (MPa) of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites, wherein; I is Flexural strength and I is Flexural modulus, A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0023] Fig. 5. Graph showing Tan delta values of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites with respect to temperature values on x-axis, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0024] Fig. 6. Graph showing the storage moduli (MPa) of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites with respect to temperature values on the x-axis, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0025] Fig. 7. Graph showing the comparative thermal conductivity coefficients (W.nr1K1) of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0026] Fig. 8. Graph showing the change in friction coefficients of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites with respect to sliding distance on x-axis, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO. Fig. 9. Graph showing the sliding distances (km) of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites with respect to the temperature values indicated on the y-axis, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0027] Fig. 10. Comparative graph showing the wear rates of PA6 / HDPE, PA6 / HDPE+0.1 GO, PA6 / HDPE+0.25 GO, PA6 / HDPE+0.5 GO and PA6 / HDPE+1 GO polymer blend nanocomposites, wherein; A is PA6 / HDPE, B is PA6 / HDPE+0.1 GO, C is PA6 / HDPE+0.25 GO, D is PA6 / HDPE+0.5 GO and E is PA6 / HDPE+1 GO.

[0028] Summary and Objects of the Invention

[0029] The invention describes a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite and a preparation method thereof. With the invention, a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend nanocomposite with maximized levels of homogeneity level is introduced. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing used in the production of graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. In the invention, all the problems encountered in incorporating GO (graphene oxide) content into polymer nanocomposites containing polyamide 6 (PA6) and high-density polyethylene (HOPE) are eliminated and a nanocomposite is introduced in which the enhancing properties of GO are effectively transferred to the nanocomposite structure. In addition, the invention eliminates the limitations of the polyamide 6 / high-density polyethylene (PA6 / HDPE) blend nanocomposite, such as unstable phase morphologies and low interface strength.

[0030] The object of the invention is to introduce a nanocomposite in which all the problems encountered in incorporating GO (graphene oxide) content into polymer nanocomposites containing polyamide 6 (PA6) and high-density polyethylene (HDPE) are eliminated and the enhancing properties of GO are effectively transferred to the nanocomposite structure. An object of the invention is to introduce a nanocomposite structure that exhibits superior mechanical properties by eliminating the limitations of the polyamide 6 / high-density polyethylene (PA6 / HDPE) blend nanocomposite, such as unstable phase morphologies and low interface strength. In the invention, maleic anhydride grafted polyethylene (MAPE) is used to increase the interface strength between PA6 and HDPE and to obtain a stable phase morphology.

[0031] In the invention, graphene oxide can be added to the polymer nanocomposite containing PA6 and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. In the invention, a negligible change in melting temperatures is achieved by increasing the GO (graphene oxide) content, and the mechanical and structural properties of the nanocomposite are enhanced by maintaining the thermal stability of the nanocomposite material. While properties such as strength are enhanced by addition of graphene oxide to the material, the advantage of using nanocomposite material is offered without a significant change in melting temperature and without loss of performance at high temperatures. Thus, the processability and temperature resistance properties of the nanocomposite material formed by the addition of GO are balanced.

[0032] With the invention, graphene oxide can be added to the polymer nanocomposite containing PAS and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. It has been observed that crystallinity decreases with the increase in GO weight ratio. The reason for this decrease in crystallinity is that the movement of PA6 and HDPE polymer chains within the crystal structure slows down due to the interaction of PA6 / HDPE and GO. In the invention, graphene oxide can be added to the polymer nanocomposite containing PA6 and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. In the invention, the increase in the GO content had a negligible effect on melting temperatures. The technical effect achieved with the increase in GO content having a negligible effect on melting temperatures is the maintenance of the thermal stability of the nanocomposite material. This property allows to increase the processability and mechanical properties of the nanocomposite without any appreciable change in melting temperature despite the addition of GO. In addition, this allows the nanocomposite to be used in a wide range of temperatures, while maintaining its thermal stability. Thus, the advantages of GO (e.g. strength increase) are achieved without adversely affecting the structural performance and usability of the material. This increases the preferability of the nanocomposite subject to the invention, especially in areas that require application at high temperatures. Thermogravimetric analysis (TGA) results reveal that the GO content has little effect on the degradation temperature (Td) and the thermal stability increases slightly.

[0033] With the invention, graphene oxide can be added to the polymer nanocomposite containing PA6 and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. With the increase in the GO weight ratio, it was observed that both the tensile and flexural properties of PA6 / HDPE+GO nanocomposites increased compared to PA6 / HDPE.

[0034] With the invention, graphene oxide can be added to the polymer nanocomposite containing PA6 and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. With the increase in the GO weight ratio, the storage modulus of the PA6 / HDPE+GO nanocomposite subject to the invention is also increased. This improvement in the storage modulus is attributed to the rigidity provided by the addition of GO to the PA6 / HDPE composite. In the invention, rigid GO particles increase the hardness of the nanocomposite, thereby limiting PA6 / HDPE deformation. The rigid structure of GO increases the hardness and load-carrying capacity of the nanocomposite, leading to lower wear rates. This makes it possible to ensure the longevity of the nanocomposite material subject to the invention and provides an advantage in high-performance applications. Another object of the invention is to introduce a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend nanocomposite with maximized levels of homogeneity level. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was additionally prevented by the addition of the solvent mixing step. Homogeneous mixing in nanocomposites manufactured by a combination of melt and solvent mixing methods enables GO to effectively transfer its outstanding mechanical properties. Thanks to the homogeneous distribution of GO, energy damping is reduced, which increases the structural strength and hardness of the nanocomposite. In addition, the good dispersion and integration of GO in the polymer matrix limits the mobility of the polymer chains, raising the glass transition temperature (Tg) and improving the thermal performance of the material. The increase in Tg and the decrease in the Tan Delta value are considered a positive effect, as they indicate that the GO is well distributed and harmoniously integrated with the matrix. This indicates that the nanocomposite has become more performant in terms of both rigidity and thermal strength.

[0035] In the invention, graphene oxide can be added to the polymer nanocomposite containing PAS and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. The addition of GO has resulted in a remarkable reduction in the friction coefficient of PA6 / HDPE nanocomposites. This increases the friction resistance of nanocomposites, allowing them to perform more efficiently. The low friction coefficients contribute to the reduction of temperatures generated during friction. This reduces temperature-induced deterioration and increases thermal strength in long-term use of the nanocomposite.

[0036] With the invention, graphene oxide can be added to the polymer nanocomposite containing PA6 and HDPE to a desirable extent, as problems such as agglomeration and homogeneous distribution problems of graphene oxide are eliminated. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. The increase in the GO content ensures that the heat generated during friction is dissipated faster. This property helps to keep the material longer lasting and thermally stable.

[0037] The graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite subject to the invention forms a more stable transfer film on steel surfaces. This film provides protection against wear, increasing the strength of the nanocomposite and reducing material loss on friction surfaces.

[0038] Detailed Description of the Invention

[0039] The invention relates to a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite and a preparation method thereof. In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing used in the production of graphene oxide-reinforced polyamide 6 / high-density polyethylene blend (PA6 / HDPE) nanocomposite, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material. Furthermore, the invention eliminates the limitations of the polyamide 6 / high-density polyethylene (PA6 / HDPE) blend nanocomposite, such as unstable phase morphologies and low interface strength. With the invention, a graphene oxide-reinforced polyamide 6 / high-density polyethylene blend nanocomposite with maximized levels of homogeneity level is introduced.

[0040] The nanocomposite subject to the invention comprises polyamide 6 (PA6), high-density polyethylene (HDPE), graphene oxide (GO), and maleic anhydride-grafted polyethylene (MAPE). In an embodiment of the invention, the nanocomposite subject to the invention comprises polyamide 6 (PA6) at a rate of 15-80% by weight, high-density polyethylene (HDPE) at a rate of 15-80% by weight, graphene oxide (GO) at a rate of 0.1 -1% by weight, and maleic anhydride grafted polyethylene (MAPE) at a rate of 5% by weight.

[0041] In an embodiment of the invention, the nanocomposite subject to the invention comprises polyamide 6 (PA6) at a rate of 75.2-76% by weight, high-density polyethylene (HDPE) at a rate of 18.8-19% by weight, graphene oxide (GO) at a rate of 0.1 -1 % by weight, and maleic anhydride-grafted polyethylene (MAPE) at a rate of 5% by weight.

[0042] The preparation method of the nanocomposite subject to the invention comprises the process steps of; i. preparing a polyamide 6 / graphene oxide (PA6 / GO) masterbatch using a temperature-controlled mechanical mixer, ii. adding formic acid and PA6 to the mechanical mixer with heater, iii. stirring the mixture to completely dissolve PA6 in formic acid, iv. adding the GO nano powder into ethanol and subjecting the GO nano powder and ethanol blend to ultrasonic processing, v. slowly adding the obtained ethanol / GO mixture to the PA6 / formic acid solution with the help of a pasteur pipette and applying the mixing process, vi. transferring the obtained PA6 / GO blend into a container and placing the blend in the fume hood before it cools down, and leaving it in the fume hood until it is completely dry and hardened in the fume hood, vii. grinding the hardened PA6 / GO blend, viii. washing the ground PA6 / GO blend with ethanol for purification from formic acid, and for this purpose, leaving the PA6 / GO mixed with ethanol in an ultrasonic bath, then separating the PA6 / GO mixture from formic acid by centrifugation, ix. repeating the process step numbered viii. until the PA6 / GO mixture is completely free of formic acid and allowing it to dry when the PA6 / GO mixture is completely separated from the formic acid, x. re-applying the grinding processes mentioned in process step numbered vii, xi. drying the prepared PA6 / GO mixture and loading the PA6 / GO blend into the thermokinetic mixer after dehumidification, xii. forming the resulting pasty mixture into a sheet by cold pressing process and subjecting the sheet containing PA6 / GO to the granulation process using a knife mill and obtaining a main additive containing GO, repeating the drying process and loading the materials into a temperature-controlled twin screw extruder xiii. diluting the masterbatch for the preparation of PA6 / HDPE+GO polymer blend nanocomposites and including in extrusion together with MAPE xiv. applying injection molding process to obtain the final product after extrusion.

[0043] In an embodiment of the invention, the preparation method of the nanocomposite subject to the invention comprises the process steps of; i. preparing a polyamide 6 / graphene oxide (PA6 / GO) masterbatch containing graphene oxide (GO) at a rate of 2% by weight, using a temperature- controlled mechanical mixer, ii. adding formic acid and PA6 to the mechanical mixer with heater and setting the temperature to 100 °C and the mechanical mixer speed to 1250-2000 rpm, iii. stirring the mixture for a minimum of 24 hours to completely dissolve PA6 in formic acid, iv. adding the GO nano powder to ethanol at a ratio of 1 / 10 by mass (GO / ethanol) and subjecting the GO nano powder and ethanol blend to ultrasonic processing for a minimum of 100 min, v. slowly adding the obtained ethanol / GO mixture to the PA6 / formic acid solution with the help of a pasteur pipette and applying the mixing process for a minimum of 48 hours, vi. transferring the obtained PA6 / GO mixture into a container at the end of a period of minimum 48 hours and placing the blend in the fume hood before it cools down, and leaving it in the fume hood for two days until it is completely dry and hardened in the fume hood, vii. grinding the hardened PA6 / GO mixture with a mechanical grinder, viii. washing the ground PA6 / GO mixture with ethanol for purification from formic acid, and for this purpose, leaving the PA6 / GO mixed with ethanol in an ultrasonic bath for a minimum of 2 hours, then separating the PA6 / GO mixture from formic acid by centrifugation at 6000-12000 rpm for a minimum of 5 minutes, ix. repeating the process step numbered viii. until the PA6 / GO mixture is completely free of formic acid and allowing it to dry in an oven at 60-85 °C when the PA6 / GO mixture is completely separated from the formic acid, x. re-applying the grinding processes mentioned in process step numbered vii, xi. drying the prepared PA6 / GO mixture at 60-85 °C for 24 hours, and loading the PA6 / GO blend into the thermokinetic mixer after dehumidification, xii. forming the resulting pasty blend into a sheet by cold pressing process and subjecting the sheet containing PA6 / GO to the granulation process using a knife mill and obtaining a masterbatch containing GO at a minimum 2% ratio by weight, repeating the drying process and loading the materials into a temperature-controlled twin screw extruder xiii. diluting the masterbatch having a 2% GO weight ratio for the preparation of PA6 / HDPE+GO polymer blend nanocomposites and including in extrusion together with MAPE xiv. applying injection molding process to obtain the final product after extrusion.

[0044] In the invention, the problem of agglomeration, which cannot be prevented in direct melt mixing, was prevented by adding an additional solvent mixing step, thus eliminating the agglomeration problem and increasing the rate of graphene oxide in the nanocomposite material.

[0045] In order to better explain the technical effect of the invention, polymer blend nanocomposites were prepared in 5 different formulations using polyamide 6 (PA6), high-density polyethylene (HOPE), maleic anhydride grafted polyethylene (MAPE), and graphene oxide (GO). MAPE was preferred to increase the interface strength between PA6 and HDPE and to achieve stable phase morphologies. The blend ratios of said 5 different polymer blend nanocomposites are shown in Table 1.

[0046] Table 1. Table showing the contents and quantities used in the analyzes regarding the analyzes carried out to reveal the technical effect of the invention.

[0047] In order to obtain the GO concentrations specified in Table 1 , the masterbatch with a weight ratio of 2% was diluted and included in the extrusion process. After the extrusion process, test samples were printed for mechanical, dynamic mechanical analysis (DMA), and tribological tests using the injection molding machine.

[0048] The effect of different GO weight ratios on the thermal, mechanical, viscoelastic, and tribological properties of PA6 / HDPE+GO nanocomposites of the invention prepared by combining melt and solvent mixing methods was examined.

[0049] The increase in the GO content had a negligible effect on melting temperatures. Furthermore, it has been observed that crystallinity decreases with the increase in GO weight ratio. The reason for this decrease in crystallinity is that the movement of PA6 and HDPE polymer chains within the crystal structure slows down due to the interaction of PA6 / HDPE and GO. Thermal gravimetric analysis (TGA) results reveal that the GO content has little effect on the degradation temperature (Td) and the thermal stability increases slightly.

[0050] With the increase in the GO weight ratio, it was observed that both the tensile and flexural properties of PA6 / HDPE+GO nanocomposites increased compared to PA6 / HDPE. Homogeneous mixing in nanocomposites manufactured by a combination of melt and solvent mixing methods enables GO to effectively transfer its outstanding mechanical properties to the composite.

[0051] The storage modulus of nanocomposites increased with the increase of the GO content at all temperatures compared to PA6 / HDPE. This improvement in the storage modulus is attributed to the rigidity provided by the addition of GO to the PA6 / HDPE composite. The damping coefficient of polymer blend nanocomposites containing PA6 / HDPE+GO has changed into small clusters of rigid GO particles dispersed in the PA6 / HDPE matrix, which prevents deformation of the matrix. The maximum Tan Delta value has decreased, limiting the matrix to homogeneous distribution and integration of GO, and Tg has increased. The increase in GO content caused a significant decrease in the friction coefficients of PA6 / HDPE nanocomposites. The low friction coefficients obtained by using GO in combination with PA6 / HDPE contributed to the reduction of friction temperatures. Furthermore, since the friction heat is rapidly dissipated by the increasing heat conduction coefficient, it has contributed to the reduction of friction temperatures with the increase in the GO weight ratio. PA6 / HDPE has been able to form a continuous transfer film. In addition, PA6 / HDPE+GO nanocomposites has formed a more stable transfer film on steel opposite surfaces as the GO content increased. In line with the friction coefficient and transfer film results, well-dispersed rigid GO has increased hardness and loadbearing capacity with increasing weight ratio, leading to lower abrasion rates.

[0052] As a result, the experimental findings, MAPE-reinforced PA6 / HDPE+GO nanocomposites of the invention have improved the thermal, mechanical, viscoelastic, and tribological properties of the material. The nanocomposite subject to the invention is recognized as excellent tribo materials with its thermal, mechanical, and viscoelastic properties that support improved wear strength and friction coefficients. The nanocomposite subject to the invention has the potential for a wide range of applications in different sectors such as the automotive and aerospace industries. The nanocomposite subject to the invention is introduced to be used as a coating in applications requiring high wear resistance and low weight, on machine elements such as gear wheels, plain bearings, rolling bearing cages, slides of machine tools, drones and unmanned aerial vehicles (AUV), automobile parts, automation robots, aerospace, military structures, sports equipment, conveyor rollers (transport of materials and goods), and machine rollers in the printing and textile sector.

Claims

CLAIMS1 . A nanocomposite, characterized in that it comprises polyamide 6 (PA6), high-density polyethylene (HDPE), graphene oxide (GO), and maleic anhydride-grafted polyethylene (MAPE).

2. A nanocomposite according to claim 1 , characterized in that it comprises polyamide 6 (PA6) at a rate of 15-80% by weight, high-density polyethylene (HDPE) at a rate of 15-80% by weight, graphene oxide (GO) at a rate of 0.1 -1 % by weight, and maleic anhydride grafted polyethylene (MAPE) at a rate of 5% by weight.

3. A nanocomposite according to claim 2, characterized in that it comprises polyamide 6 (PA6) at a rate of 75.2-76% by weight, high-density polyethylene (HDPE) at a rate of 18.8-19% by weight, graphene oxide (GO) at a rate of 0.1 -1% by weight, and maleic anhydride-grafted polyethylene (MAPE) at a rate of 5% by weight.

4. A nanocomposite preparation method, characterized in that it comprises the process steps of; i. preparing a polyamide 6 / graphene oxide (PA6 / GO) masterbatch using a temperature-controlled mechanical mixer, ii. adding formic acid and PA6 to the mechanical mixer with heater,Hi. stirring the mixture to completely dissolve PA6 in formic acid, iv. adding the GO nano powder into ethanol and subjecting the GO nano powder and ethanol blend to ultrasonic processing, v. slowly adding the obtained ethanol / GO blend to the PA6 / formic acid solution with the help of a pasteur pipette and applying the mixing process, vi. transferring the obtained PA6 / GO mixture into a container and placing the blend in the fume hood before it cools down, and leaving it in the fume hood until it is completely dry and hardened in the fume hood, vii. grinding the hardened PA6 / GO mixture, viii. washing the ground PA6 / GO mixture with ethanol for purification from formic acid, and for this purpose, leaving the PA6 / GO mixed with ethanol in an ultrasonic bath, then separating the PA6 / GO mixture from formic acid by centrifugation,ix. repeating the process step numbered viii. until the PA6 / GO mixture is completely free of formic acid and allowing it to dry when the PA6 / GO mixture is completely separated from the formic acid, x. re-applying the grinding processes mentioned in process step numbered vii, xi. drying the prepared PA6 / GO mixture and loading the PA6 / GO mixture into the thermokinetic mixer after dehumidification, xii. forming the resulting pasty mixture into a sheet by cold pressing process and subjecting the sheet containing PA6 / GO to the granulation process using a knife mill and obtaining a main additive containing GO, repeating the drying process and loading the materials into a temperature-controlled twin screw extruder xiii. diluting the masterbatch for the preparation of PA6 / HDPE+GO polymer blend nanocomposites and including in extrusion together with MAPE xiv. applying injection molding process to obtain the final product after extrusion.

5. A preparation method according to claim 4, characterized in that it comprises the process steps of; i. preparing a polyamide 6 / graphene oxide (PA6 / GO) masterbatch containing graphene oxide (GO) at a rate of 2% by weight, using a temperature- controlled mechanical mixer, ii. adding formic acid and PA6 to the mechanical mixer with heater and setting the temperature to 100 °C and the mechanical mixer speed to 1250-2000 rpm, iii. stirring the mixture for a minimum of 24 hours to completely dissolve PA6 in formic acid, iv. adding the GO nano powder to ethanol at a ratio of 1 / 10 by mass (GO / ethanol) and subjecting the GO nano powder and ethanol mixture to ultrasonic processing for a minimum of 100 min, v. slowly adding the obtained ethanol / GO mixture to the PA6 / formic acid solution with the help of a pasteur pipette and applying the mixing process for a minimum of 48 hours, vi. transferring the obtained PA6 / GO mixture into a container at the end of a period of minimum 48 hours and placing the mixture in the fume hood before it cools down, and leaving it in the fume hood for two days until it is completely dry and hardened in the fume hood,vii. grinding the hardened PA6 / GO mixture with a mechanical grinder, viii. washing the ground PA6 / GO mixture with ethanol for purification from formic acid, and for this purpose, leaving the PA6 / GO mixed with ethanol in an ultrasonic bath for a minimum of 2 hours, then separating the PA6 / GO mixture from formic acid by centrifugation at 6000-12000 rpm for a minimum of 5 minutes, ix. repeating the process step numbered viii. until the PA6 / GO mixture is completely free of formic acid and allowing it to dry in an oven at 60-85 °C when the PA6 / GO mixture is completely separated from the formic acid, x. re-applying the grinding processes mentioned in process step numbered vii, xi. drying the prepared PA6 / GO mixture at 60-85 °C for 24 hours, and loading the PA6 / GO mixture into the thermokinetic mixer after dehumidification, xii. forming the resulting pasty blend into a sheet by cold pressing process and subjecting the sheet containing PA6 / GO to the granulation process using a knife mill and obtaining a masterbatch containing GO at a minimum 2% ratio by weight, repeating the drying process and loading the materials into a temperature-controlled twin screw extruder xiii. diluting the masterbatch having a 2% GO weight ratio for the preparation of PA6 / HDPE+GO polymer blend nanocomposites and including in extrusion together with MAPE xiv. applying injection molding process to obtain the final product after extrusion.

6. A nanocomposite prepared by a method according to any one of claim 4 or 5.

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