A method of obtaining a composite with position-dependent mechanical properties and a composite obtained by the method

Abstract

The present invention relates to a method (100) of obtaining composites having an optimizable balance of strength and toughness by combining macro- and micro-scale composites, and to composites obtained by the method (100).

Description

[0001] A METHOD OF OBTAINING A COMPOSITE WITH POSITIONDEPENDENT MECHANICAL PROPERTIES AND A COMPOSITE OBTAINED BY THE METHOD

[0002] Technical Field

[0003] The present invention relates to a method of obtaining composites having an optimizable balance of strength and toughness by combining macro- and microscale composites, and to composites obtained by the method.

[0004] Background of the Invention

[0005] Stainless steel, cobalt alloys, titanium alloys and UHMWPE (Ultra High Molecular Weight Polyethylene) are used in biomedical applications. Stainless steel and cobalt alloys are quite heavy. They have disadvantages due to their very high specific modulus and specific strength values. Furthermore, the biocompatibility of cobalt alloys is limited. Titanium alloys, which are lighter by weight than related materials, are known for their high tensile strength and toughness close to human bone; however, although being strong, they lack structural specification in stress distribution. Ultra-high molecular weight polyethylene, in turn, has the advantage of low density, yet its mechanical properties are quite low.

[0006] The fact that standard composite materials have homogeneous particle distribution does not allow the mechanical properties to change according to the position. Therefore, it is difficult to achieve a balance between properties such as strength and toughness. The hardness and elastic modulus values of composite materials produced by conventional methods are usually fixed within a certain range and cannot be adjusted. In conventional composites, toughness and strength are mutually exclusive and difficult to be achieved simultaneously. With conventional methods, combining mechanically different components can lead to stress concentration, which limits the lifetime of the material.

[0007] The systems and methods used in the state of art have disadvantages that limit the production of biocompatible composite materials. In the current production process, the use of nanocomposites at macro- and micro-scale, adjustment of particle amount and distribution, reduction of stress concentration, potential for embedded functionality such as self-repair or adaptation, obtaining different mechanical balances by adjusting the amount of particles according to position, establishing a balance between properties such as strength and toughness, and offering production and design flexibility are not possible.

[0008] For this reason, there is a need for a new composite production method which overcomes the above-mentioned shortcomings.

[0009] The Chinese patent document no. CN115961241, an application included in the state of the art, discloses a bionic hierarchical structure coating system. The invention subject to the said Chinese patent document discloses a bionic hierarchical structure coating which belongs to the technical field of surface coatings. The coating consists of a composite layer comprising a transition layer TiAlN, a hard layer AlCrSiN and a soft layer Ti. The thickness of the transition layer is 0.4 pm, the thickness of a single hard layer is 1.0 + / -0.2 pm and the thickness of a single soft layer is 0.2 pm. The hard layer AlCrSiN comprises nanoscale amorphous Si3N4 particles and these particles are homogeneously distributed on the hard layer. This designed bionic hierarchical structure coating provides toughening in the AlCrSiN layer and between the AlCrSiN / Ti layers, the hardness of the coating is not reduced, toughness integration thereof is achieved, and meanwhile the coating has excellent friction resistance and high film / substrate bonding strength and is suitable for different application environments.

[0010] Summary of the Invention An object of the present invention is to develop a method which allows mechanical properties such as elastic modulus, strength and toughness to be adjusted by combining the macro- and micro-scale and facilitates obtaining optimal material properties for specific applications; and to produce composites related to the method.

[0011] Another object of the present invention is to realize a composite production method which enables the stress concentration during combining mechanically different components to be reduced and the overall performance and durability of the material to be improved.

[0012] A further object of the present invention is to realize a composite production method which enables biocompatible nanocomposite materials suitable for use in biomedical applications to be used.

[0013] A further object of the present invention is to realize a composite and production method which offers embedded functionalities such as self-repair and enables the material to be long-lasting and reliable.

[0014] A further object of the present invention is to realize a composite production method which allows the material properties to be customized for various applications and requirements and makes the production process more flexible and adaptable.

[0015] A further object of the present invention is to realize a composite manufacturing method which enables composites that make rapid prototyping and rapid adaptation to market changes possible to be obtained.

[0016] A further object of the present invention is to realize a composite production method which reduces waste generation and improves environmental sustainability through optimized production processes and material use. Detailed Description of the Invention

[0017] “A Method of Obtaining a Composite with Position-Dependent Mechanical Properties and a Composite Obtained by the Method” realized to fulfd the objectives of the present invention is shown in the figure attached, in which:

[0018] Figure 1 is a flowchart of the inventive method.

[0019] 100. Method

[0020] The inventive production method (100) of composites having an optimizable balance of strength and toughness by combining macro- and micro-scale composites comprises the steps of producing macro-scale nanocomposites (101); and coating micro-scale composite on macro-scale composite (102).

[0021] At the step of producing macro-scale nanocomposites (101) of the inventive method (100), biopolymer, which can be polyvinyl pyrrolidone, and nanoclay components, which can be bentonite or halloysite, are used in a thermoplastic matrix, which can be polyethylene or polypropylene, in order to produce macro-scale nanocomposites by using biocompatible polymers and nano-sized reinforcement materials. Macroscale composites with customizable dimensions (e.g. centimeters in length & width and millimeters in thickness) are obtained by carrying out an injection molding process by means of combining melt and solvent-based composite production methods. In this process, polyvinyl pyrrolidone and nanoclay nanocomposite obtained by using water-based solvent method is integrated with the thermoplastic base matrix through melt mixing method, thereby a macro composite with three components is obtained. The obtained macro-scale nanocomposites have high fracture resistance (e.g., 10-30 kJ / m2) but low strength (e.g., 10-20 MPa) and moderate elastic modulus (e.g., 70-200 MPa). Macroscale nanocomposites are materials that have high ductility and toughness with low elastic modulus and strength values.

[0022] At the step of coating micro-scale composite on macro-scale composite (102) of the inventive method (100), nanocomposites containing polyvinylpyrrolidone (PVP) / nanoclay (Halloysite and Bentonite) or similar materials are coated on the surface of the macro-scale composite material by spin coating technique by using alcohol-based dispersions. The coating process is carried out under different combinations of concentrations and thicknesses (between 5 and 100 micrometers), which can range from 1 to 10 layers and the particle density of each layer can be adjusted among 1%, 5%, 10%, 20%, 20%, 40%, and 60%, and this process enables the layers to be deposited progressively. By using the spin coating method, the film thicknesses formed by dispersions of nanocomposites at different microliters are measured with a profilometer. The data obtained from these measurements enables the film heights required to achieve different concentration values to be precisely adjusted. Each layer can be adjusted so as to be 5-100 pm thick and in the desired position, and the number of layers may vary between 1-10. The coating has a particle distribution that varies according to the height and enables a precise control over the mechanical properties to be realized. Adjusting the particle concentration according to the position causes significant changes in elastic modulus and hardness. The elastic modulus is gradually increased from the level of polymeric materials (~0.2 GPa) at the lowest layer to the level of metals and ceramics (-100 GPa) at the top layer. In the same way, the hardness can be increased from the level of polymeric materials (-10 MPa) to the level of high carbon steels (-1500 MPa).

[0023] The composite material obtained by following the steps of the inventive method (100) is used as a potential bone and dental implant material in biomedical applications by virtue of its toughness and strength balance. It is also used in various engineering applications that require a balance between toughness and strength. Within these basic concepts; it is possible to develop various embodiments of the inventive “A Method (100) of Obtaining a Composite with Position-Dependent Mechanical Properties and a Composite Obtained by the Method (100)”; the invention cannot be limited to examples disclosed herein and it is essentially according to claims.

Claims

CLAIMS1. A production method (100) of composites having an optimizable balance of strength and toughness by combining macro- and micro-scale composites; characterized in that it comprises the steps of producing macro-scale nanocomposites (101); and coating micro-scale composite on macro-scale composite (102).

2. A method (100) according to Claim 1; characterized in that at step of producing macro-scale nanocomposites (101), biopolymer, which can be polyvinyl pyrrolidone, and nanoclay components, which can be bentonite or halloysite, are used in a thermoplastic matrix, which can be polyethylene or polypropylene, in order to produce macro-scale nanocomposites by using biocompatible polymers and nano-sized reinforcement materials.

3. A method (100) according to Claim 1 or 2; characterized in that at step of producing macro-scale nanocomposites (101), macro-scale composites with customizable dimensions are obtained by carrying out an injection molding process by means of combining melt and solvent-based composite production methods.

4. A method (100) according to Claim 3; characterized in that at step of producing macro-scale nanocomposites (101), polyvinyl pyrrolidone and nanoclay nanocomposite obtained by using water-based solvent method is integrated with the thermoplastic base matrix through melt mixing method and a macro composite with three components is obtained.

5. A method (100) according to Claim 1; characterized in that at step of coating micro-scale composite on macro-scale composite (102), nanocomposites containing polyvinylpyrrolidone (PVP) / nanoclay (Halloysite and Bentonite) are coated on the surface of the macro-scale composite material by spin coating technique by using alcohol-based dispersions.

6. A method (100) according to Claim 5; characterized in that at step of coating micro-scale composite on macro-scale composite (102), the coating process is carried out under different combinations of concentration and thickness between 5 and 100 micrometers, which range from 1 to 10 layers and the particle density of each layer can be adjusted among 1%, 5%, 10%, 20%, 40%, and 60%, enabling the layers to be deposited progressively.

7. A composite material obtained by following the steps of method (100) above, characterized in that it can be used as a potential bone and dental implant material in biomedical applications by virtue of its toughness and strength balance, and as a composite in engineering applications requiring a balance between toughness and strength.

Images