Composite material containing thermoplastic polyurethane and graphene oxide, use and manufactring meyhod thereof

Abstract

The present disclosure provides a composite material containing thermoplastic polyurethane and graphene oxide having excellent mechanical properties and heat dissipation at the same time by adding graphene oxide into thermoplastic polyurethane and a use thereof, and a cable made from the composite material can have good safety and long lifespan.

Description

[Technical Field]

[0001] This invention relates to composite materials, particularly composite materials comprising thermoplastic polyurethane (TPU) and graphene oxide. [Previous Technology]

[0002] Thermoplastic polyurethane (TPU) is known for its excellent transparency, abrasion resistance, anti-aging and oil resistance. It also performs well in terms of load capacity and tensile strength. It is a multifunctional material that can be manufactured by methods such as injection molding, extrusion molding and blow molding. It is widely used in products such as sports shoes, raincoats, automotive hoses, protective gloves and cables.

[0003] TPU plays a crucial role in cable manufacturing, especially in cable sheath applications where a balance needs to be struck between tensile strength, flame retardancy, and thermal deformation. Furthermore, because the passage of current through a cable generates high temperatures, its heat dissipation performance is critical for extending its service life. Good heat dissipation helps prevent overheating and thermal damage, ensuring safe operation and allowing the cable to carry larger currents, thus enabling a reduction in wire diameter for greater flexibility. Therefore, achieving the optimal balance between mechanical properties and heat dissipation is a significant challenge in cable-related fields. [Summary of the Invention]

[0004] The present invention provides a composite material and its use in manufacturing cables, by adding graphene oxide to thermoplastic polyurethane to achieve the advantages of having both excellent mechanical properties and heat dissipation, and the cables made therefrom have good safety, heat dissipation, flexibility and long service life.

[0005] In order to achieve the above objectives, the present invention provides a composite material comprising thermoplastic polyurethane and graphene oxide, wherein the weight ratio of thermoplastic polyurethane to graphene oxide is 9:1 to 7:3.

[0006] In a composite material of one embodiment of the present invention, the weight ratio of thermoplastic polyurethane to graphene oxide is 4:1.

[0007] In a composite material of one embodiment of the present invention, graphene oxide is modified with amine groups.

[0008] In a composite material of one embodiment of the present invention, the weight average molecular weight of the thermoplastic polyurethane may be 130,000.

[0009] In a composite material of one embodiment of the present invention, the tensile strength measured according to ASTM D638 is greater than or equal to 10 megapascals (MPa).

[0010] In a composite material according to an embodiment of the present invention, the elongation measured according to ASTM D638 may be greater than or equal to 300%.

[0011] In a composite material of one embodiment of the present invention, the withstanding voltage measured according to ASTM D149 is greater than or equal to 2.0 kV.

[0012] In a composite material of one embodiment of the present invention, the leakage current measured according to ASTM D149 is less than 0.5 milliamperes (mA).

[0013] On the other hand, the present invention also provides the use of a composite material comprising thermoplastic polyurethane and graphene oxide for manufacturing cables.

[0014] On the other hand, the present invention also provides a method for manufacturing a heat dissipation composite material for cables, comprising: modifying graphene oxide with an aminosilane coupling agent, and then mixing thermoplastic polyurethane and modified graphene oxide in a weight ratio of 9:1 to 7:3 using a twin-screw extruder to produce a heat dissipation composite material for cables.

[0015] The effects of the present invention are not limited to those mentioned above, and those skilled in the art to which the present invention pertains can clearly understand from the following description the effects not mentioned above.

Implementation Method

[0016] The detailed features and advantages of the present invention are described in detail in the following embodiments. The content is sufficient to enable anyone skilled in the art to understand the technical content of the present invention and implement it accordingly. Furthermore, based on the content disclosed in this specification, the scope of the patent application, and the drawings, anyone skilled in the art can easily understand the relevant objectives and advantages of the present invention. The following embodiments are further detailed in illustrating the viewpoints of the present invention, but are not intended to limit the scope of the present invention in any way.

[0017] The present invention provides a composite material comprising thermoplastic polyurethane (TPU) and graphene oxide, wherein the weight ratio of thermoplastic polyurethane to graphene oxide is 9:1 to 7:3.

[0018] In a composite material of one embodiment of the present invention, the weight ratio of thermoplastic polyurethane to graphene oxide is 4:1.

[0019] In a composite material of one embodiment of the present invention, the thermoplastic polyurethane used in the present invention has a weight-average molecular weight of 130,000, and the graphene oxide used in the present invention is amine-modified graphene oxide, type O-PG, with a particle size of 2~3 nm and an oxygen content ≥40% by weight (wt%). The dispersibility, adhesion, and compatibility of the amine-modified graphene oxide in the thermoplastic polyurethane are improved.

[0020] The preparation, testing and test results of composite materials according to several embodiments of the present invention are described below.

[0021] Preparation method: Graphene oxide is modified with an aminosilane coupling agent, and then the modified graphene oxide and TPU are mixed in different ratios (as shown in Table 1) to form a composite material using a twin-screw extrusion mixing mechanism. The sample is then made by injection molding or extrusion molding.

[0022] The property testing method is as follows:

[0023] 1. Tensile strength, elongation, and Young's modulus: These were determined according to ASTM D638 TYPE IV. According to this procedure, a dog-bone shaped sample with a total length of 165 mm, a thickness of 3.2 mm (1 / 8 inch), and a gauge length of 50 mm (2 inches) was fixed between two clamps at room temperature. The sample was stretched at a tensile rate of 50 mm / min until it broke, and the tensile strength and elongation were recorded. The Young's modulus was calculated from the tensile force and the amount of deformation of the sample.

[0024] 2. Hardness: A dog bone-shaped sample with dimensions of 2 inches × 2 inches and a minimum thickness of 6.4 mm (0.25 inches) was used to determine the hardness using a Shore D hardness tester according to the specifications of ASTM D2240.

[0025] 3. Surface resistance: Measured according to ASTM D257. According to this procedure, a sample with dimensions of 10cm × 10cm × 2mm is connected to two electrodes, a voltage is applied and the current flowing through the sample is recorded, and the surface resistance is calculated from the measured voltage and current.

[0026] 4. Withstand voltage test: The test shall be performed in accordance with the ASTM D149 standard. According to this procedure, a sample with dimensions of 10cm×10cm×2mm is connected to two electrodes, the leakage current at different voltages is recorded, and a voltage is applied until dielectric breakdown occurs, and the voltage at the breakdown point is recorded (i.e., withstand voltage).

[0027] 5. Thermal conductivity: Determined according to ISO 22007-2 (Instantaneous Plane Heat Source (Hot Plate) Method). According to this procedure, a disc-shaped heat source is placed in the middle of a 10cm×10cm×3mm sample and the disc-shaped heat source is heated. The thermal conductivity of the sample is calculated by measuring the change in the temperature of the hot plate over time.

[0028] 6. Cooling efficiency: A 10cm×10cm×4mm sample was heated for 900 seconds with a 0.36W heater and the sample temperature was recorded. The cooling efficiency of each sample was calculated using Equation 1 based on the measured temperature. Equation 1: Cooling efficiency = (Example temperature - Comparative example temperature) / Comparative example temperature × 100%.

[0029] In addition, the composite material of the present invention was further subjected to aging, oil resistance, hydrolysis resistance, acid resistance, alkali resistance, low temperature elongation, and tear resistance tests. The following describes each treatment and test.

[0030] Aging resistance test: According to ASTM D412, the sample is placed in an oven at 110°C and subjected to a constant temperature of 110°C with air exchange 8 to 20 times. After 168 hours, the physical properties of the sample are tested.

[0031] Oil resistance test: According to ASTM D412, the sample is placed in the test oil and placed in an oven at 110°C. The sample is subjected to a constant temperature of 110°C and air is exchanged 8 to 20 times. After 168 hours, the physical properties of the sample are tested.

[0032] Hydrolysis resistance test: According to the IEC 62893-2 standard, the sample is placed in circulating water at 80°C, and after being kept at a constant temperature of 80°C and simultaneously subjected to air exchange 8 to 20 times, the physical properties of the sample are tested after 168 hours.

[0033] Acid resistance test: According to the IEC 60811-404 standard, the sample was placed in an oxalic acid aqueous solution at 23°C for 5 hours and the physical properties of the sample were tested.

[0034] Alkali resistance test: According to IEC 60811-404, the sample was placed in a sodium hydroxide aqueous solution at 23°C for 5 hours and the physical properties of the sample were tested.

[0035] Low temperature elongation test: According to the IEC 60811-505 standard, the sample is placed in a -40°C freezer for 4 hours and the elongation of the sample is tested.

[0036] Tear resistance test: According to Section 5.5 of IEC 62893-2, the tensile force required to tear a 100mm×30mm×3mm sample to the stop line (80mm distance) at a tensile rate of (250 ± 50) mm / min is measured.

[0037] The change rate is the ratio of the physical properties of the sample after treatment to the physical properties of the sample before treatment. For example, the tensile strength of Example 1 is 23.133 MPa, and the tensile strength of Example 1 after aging treatment is 21.887 MPa. Then, the change rate (%) of the tensile strength of Example 1 after aging can be calculated as 23.133 / 21.887*100%=94.6.

[0038] Table 1 below reveals the composition of pure TPU (Comparative Example 1) and TPU / graphene oxide composite materials (Examples 1-5) and the results of their property tests before and after aging.

[0039] Table 1 Comparative Example 1 (Pure TPU) Example 1 Example 2 Example 3 Example 4 Example 5 Graphene oxide (wt%) 0 10 14 18 20 30 TPU (wt%) 100 90 86 82 80 70 Molding method Extrusion Extrusion Extrusion Extrusion Extrusion Extrusion Tensile strength (MPa) 24.893 23.133 22.081 21.030 20.573 12.416​ Tensile strength after aging (MPa) 29.537 21.887 21.837 20.744 19.488 11.742 Change in tensile strength after aging (%) >100 94.6 98 99 95 92 Elongation (%) 1247.057 954.99 867.91 822.507 788.623 534.819 Elongation after aging (%) 1089.525 861.79 753.15 78.315 683.636 382.094 Change in elongation after aging (%) 87 90 88 86 87 71 Young's modulus (MPa) 2.549 13.33 16.724 18.823 22.677 41.988 Young's modulus (MPa) after aging 3.301 12.37 15.91 16.516 18.928 29.265 Young's modulus change rate after aging (%) >100 92 95 88 83 70 hardness 42 52 52 46 47 42 Hardness after aging 39 48 50 44 43 40 Surface resistivity (Ω / cm) 4.77*10^11 2.76*10^11 3.16*10^11 3.56*10^11 3.73*10^11 4.04 * 10^11 Withstand voltage (kV) 5 5 5 5 5 5 Leakage current (mA) at 5 kV 0.01 0.105 0.105 0.105 0.107 0.112 Cooling efficiency (%) - 10~11 14~15 19~21 23~25 32~35 Thermal conductivity (W / mK) 0.3 0.32 0.45 0.48 0.91 1.04

[0040] As shown in Table 1, compared with pure TPU without graphene oxide (comparative example), TPU with graphene oxide (Examples 1-5) can have better cooling efficiency while maintaining good mechanical properties. The "good mechanical properties" include tensile strength greater than or equal to 10 MPa and elongation greater than or equal to 300%.

[0041] Table 2 below reveals the composition of pure TPU (comparative example) and TPU / graphene oxide composite materials (Examples 3 and 4) and the test results of their properties after aging, oil resistance, hydrolysis resistance, acid resistance, alkali resistance, low temperature elongation and tear resistance.

[0042] Table 2 Comparative Example 1 (Pure TPU) Example 3 Example 4 Graphene oxide (wt%) 0 18 20 TPU (wt%) 100 82 80 Change in tensile strength after aging (%) 81 86 85 Change in elongation after aging (%) 124 96 95 Change in tensile strength (%) after oil resistance test 71 74 75 Elongation change (%) after oil resistance test 106 90 86 Change in tensile strength (%) after hydrolysis resistance test 75 72 70 Elongation change (%) after hydrolysis resistance test 114 92 93 Low temperature elongation (%) 482 170 150 ​Change in tensile strength (%) after acid resistance test 109 80 77 Elongation (%) after acid resistance test 527 430 505 Change in tensile strength (%) after alkali resistance test 88 77 78 Elongation (%) after alkali resistance test 533 405 450 Tear resistance (N / mm) 64 46 28

[0043] As shown in Table 2, the tensile strength and elongation of the composite material of the present invention change by more than 70% after aging, more than 70% after oil resistance testing, more than 70% after hydrolysis resistance testing, more than 60% after acid resistance testing, and more than 100% after alkali resistance testing. These experimental results demonstrate that the composite material of the present invention retains similar mechanical properties to those before treatment after aging, oil resistance, hydrolysis resistance, acid resistance, and alkali resistance testing, proving that the composite material of the present invention possesses anti-aging, oil resistance, hydrolysis resistance, acid resistance, and alkali resistance characteristics. Furthermore, the low-temperature elongation of the composite material of the present invention is greater than 30%, and the tear resistance is greater than 25 N / mm.

[0044] The composite material of the present invention has good aging resistance and can maintain its physical properties and appearance even after prolonged exposure to high temperature, oxidation and other environments. This characteristic is beneficial to the long-term reliability of the cable and can provide the cable with good safety and long service life.

[0045] The composite material of the present invention has good oil resistance and can maintain stable properties in contact with oil or oil-contaminated environments. This characteristic is beneficial for its application in industrial and specific environments, and can provide cables with good safety and long service life.

[0046] The composite material of the present invention has good acid and alkali resistance, and can resist the corrosion of certain concentrations of acids and alkalis, so that it can maintain stable properties in environments with strong chemical corrosion. This characteristic is beneficial for its application in specific environments and can provide cables with good safety and long service life.

[0047] The composite material of the present invention has good hydrolysis resistance and is not easily degraded by moisture. This characteristic is beneficial for its application in outdoor or high-humidity environments and can provide the cable with good safety and long service life.

[0048] The composite material of the present invention has good tear resistance and can resist external physical damage. This characteristic is beneficial for protecting the internal structure and functional components of the cable from damage, and can provide the cable with good safety.

[0049] In summary, the composite material provided by the present invention achieves the advantages of both excellent mechanical properties and heat dissipation by adding graphene oxide to thermoplastic polyurethane. Furthermore, the composite material of the present invention has properties of anti-aging, oil resistance, hydrolysis resistance, acid resistance, alkali resistance, and tear resistance. In addition, cables manufactured from it can have good safety, heat dissipation, flexibility, and long service life.

[0050] Although the present invention has been disclosed above with reference to the foregoing embodiments, it is not intended to limit the present invention. Any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention. For the scope of protection defined by the present invention, please refer to the appended claims. [Simplified Explanation of the Diagram]

[0051] None.

Claims

1. A composite material comprising: thermoplastic polyurethane (TPU); and graphene oxide; wherein, The weight ratio of thermoplastic polyurethane to graphene oxide is 4:1; the graphene oxide is modified with amine groups and has an oxygen content ≥40% by weight; the weight average molecular weight of the thermoplastic polyurethane is 130,000; the tensile strength measured according to ASTM D638 is greater than or equal to 10 MPa; the elongation measured according to ASTM D638 is greater than or equal to 300%; the withstand voltage measured according to ASTM D149 is greater than or equal to 2.0 kV; and the leakage current measured according to ASTM D149 is less than 0.5 mA.

2. Use of a composite material as described in claim 1 for manufacturing a cable.

3. A method for manufacturing a composite material as described in claim 1, comprising: modifying graphene oxide with an aminosilane coupling agent, and then mixing thermoplastic polyurethane and modified graphene oxide in a weight ratio of 4:1 using a twin-screw extruder to produce a heat dissipation composite material for cables, wherein the thermoplastic polyurethane has a weight average molecular weight of 130,000; and the oxygen content of the graphene oxide is ≥40% by weight.