High-thermal-radiation degradable composite film as well as preparation method and application thereof

Abstract

The invention discloses a degradable composite film with high thermal radiation as well as a preparation method and application of the degradable composite film. The degradable composite film is prepared from a degradable composite material. The preparation raw materials of the composite material comprise 99.4%-99.9945% of a high thermal radiation filler # imgabs 0 # degradable high polymer material and an auxiliary agent # imgabs 1 #. The graphene oxide is used as a thermal radiation enhancer, the surface of the graphene oxide has a large number of hydrophilic groups such as hydroxyl and carboxyl, and the graphene oxide can be bonded with the surface of the degradable high polymer material through hydrogen bonds, so that the thermal radiation of the degradable high polymer material is enhanced, and the thermal radiation of the degradable high polymer material is enhanced. Meanwhile, the graphene oxide in the composite film can play a role in soil bacteriostasis, growth of crops is facilitated, and meanwhile land resources can be further fully utilized.

Description

Technical Field

[0001] The present invention belongs to the technical field of thin film manufacturing, and relates to a high heat radiation degradable composite film, a preparation method thereof and an application thereof. Background Art

[0002] China is a traditional agricultural country with a large planting area of crops. During the growth process of crops, they are easily affected by factors such as low temperature and drought, resulting in crop yield reduction. In order to improve the survival rate and yield of crops, a large amount of plastic mulch is needed in the annual agricultural production process. The use of plastic mulch can achieve the effects of keeping the crops and soil warm, moisturizing, promoting growth and increasing production. Traditional plastic mulch has problems such as difficult decomposition, long decomposition period, and easy environmental pollution after use. Therefore, the research, development and use of new degradable mulch are imminent. The new biodegradable mulch is a plastic film made of polymers that can be completely decomposed by microorganisms. After being covered and used under different environmental conditions, this kind of mulch generally begins to degrade in 30 - 150 days, and can be completely decomposed by microorganisms in a short time after crop harvest, and finally converted into carbon dioxide and water. Both European and Chinese standards require that more than 90% of the mulch be decomposed by microorganisms into carbon dioxide and water within 180 days under composting conditions.

[0003] However, although many raw materials with degradation ability are currently available for the preparation of mulch, compared with traditional polyethylene films, there are some gaps in the weather resistance and temperature regulation of degradable mulch, and it is difficult to play a long-term protection role during the entire growth cycle of crops. At the same time, in order to cope with the low temperature in the north, it is necessary to improve the thermal performance of the mulch. Therefore, how to screen raw materials to prepare high-stability high heat radiation degradable mulch is of great significance for environmental protection and agricultural development. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A degradable composite material, the preparation raw materials of the composite material comprising a high heat radiation filler 99.4% - 99.9945% of a degradable polymer material and an additive

[0006] According to an embodiment of the present invention, the high heat radiation filler is graphene oxide. Preferably, the graphene oxide is added in the form of a graphene oxide solution, for example, added in the form of an aqueous graphene oxide solution. Preferably, the mass concentration of the aqueous graphene oxide solution is 0.1 - 2%, and exemplarily 0.7%. In the present invention, the thermal radiation emissivity of graphene oxide is 0.95.

[0007] According to an embodiment of the present invention, the graphene oxide solution can be prepared by a method known in the art. Preferably, the graphene oxide solution is prepared according to the method described in the patent document CN106587018B; more preferably, the preparation method of the graphene oxide solution includes: preparing an aqueous solution of graphene oxide by using a high-frequency alternating current pulse method, for example: first, an anode and a cathode plate of high-purity graphite with dimensions of 600 * 300 * 80 are placed in an electrolytic oxidation tank, and the distance between the anode and cathode plates is 70 mm. Then, 0.09% sulfuric acid electrolyte is poured into the tank, the power supply is turned on, and electrolytic oxidation is carried out to prepare a graphene aggregate sol. The anode and cathode plates are separated by a plastic mesh, and the effective current density is controlled at 100 A / m 2 ; the power supply pulse frequency is 60 Hz; the effective voltage is 20 V; the temperature is controlled at 60 °C. After reacting for 200 hours, when the concentration of the graphene sol reaches 0.7%, the oxidation reaction ends, and the solution in the tank is the graphene oxide solution. Alternatively, the above graphene oxide solution can be freeze-dried to obtain graphene oxide powder, which is configured as a solution when in use.

[0008] According to an embodiment of the present invention, the biodegradable polymer material is selected from at least two of polylactic acid (PLA), polybutylene adipate terephthalate (PBAT), and polyvinyl alcohol (PVA). For example, the biodegradable polymer material is a combination of PLA and PBAT (for example, the mass ratio of the two is 1:6 - 9, for example, 1:9), or a combination of PLA and PVA (for example, the mass ratio of the two is 1:6 - 9, for example, 1:9), or a combination of PBAT and PVA (for example, the mass ratio of the two is 1:6 - 9, for example, 1:9), or a combination of PLA, PBAT, and PVA (for example, the mass ratio of the three is 1:6 - 9:6 - 9, for example, 1:1:9).

[0009] According to an embodiment of the present invention, the additive contains at least one of an antioxidant, an ultraviolet absorber, a light stabilizer, and a dispersant.

[0010] According to an embodiment of the present invention, the antioxidant is selected from at least one of 1010, 168, 1076, B215, and B225.

[0011] According to an embodiment of the present invention, the ultraviolet absorber is selected from at least one of UV-928, UV-327, UV-531, and UV-326.

[0012] According to an embodiment of the present invention, the light stabilizer is selected from at least one of 944, 622, and 770.

[0013] According to an embodiment of the present invention, the dispersant is vinyl bisstearamide.

[0014] Preferably, the auxiliary agent is a mixture of an antioxidant, an ultraviolet absorber, a light stabilizer, and a dispersant. Among them, the mass ratio of the antioxidant, the ultraviolet absorber, the light stabilizer, and the dispersant is 1:1:1:1. Exemplarily, the content of the auxiliary agent is 1‰.

[0015] According to an embodiment of the present invention, among the preparation raw materials of the composite material, the content of the high heat radiation filler is exemplarily 1‰.

[0016] According to an embodiment of the present invention, among the preparation raw materials of the composite material, the content of the degradable polymer material is exemplarily 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.85%, 99.87%, 99.89%, or 99.9%.

[0017] According to an embodiment of the present invention, the composite material is obtained by mixing the above-mentioned preparation raw materials.

[0018] According to an embodiment of the present invention, in the composite material, graphene oxide is bonded to the surface of the polymer material through hydrogen bonds via the hydrophilic groups on its surface. In the present invention, the surface of the graphene oxide has a large number of hydrophilic groups such as hydroxyl groups and carboxyl groups, which can be bonded to the surface of the polymer material through hydrogen bonds, enhancing the structural strength of the composite material.

[0019] The present invention also provides a method for preparing the above-mentioned composite material. The preparation method includes: mixing the preparation raw materials of the above-mentioned composite material to obtain the composite material.

[0020] The present invention also provides the application of the above-mentioned composite material in the agricultural field. For example, it is used to prepare plastic mulch, and more specifically, it is used to prepare a high heat radiation degradable composite plastic mulch.

[0021] The present invention also provides a degradable composite film, and the degradable composite film is a film of the above-mentioned composite material.

[0022] According to an embodiment of the present invention, the degradable composite film is used as plastic mulch, specifically, agricultural plastic mulch. The plastic mulch of the present invention has the dual properties of high heat radiation and degradability, that is, it has the ability of degradability, weather resistance, and temperature regulation.

[0023] According to an embodiment of the present invention, the heat radiation rate of the degradable composite film is 0.90 - 0.95.

[0024] According to an embodiment of the present invention, the thickness of the degradable composite film is 0.01 - 0.015 mm, exemplarily 0.01 mm.

[0025] According to an embodiment of the present invention, the color of the degradable composite film is black.

[0026] According to an embodiment of the present invention, the elongation at break of the degradable composite film after being frozen at -20°C for 2 hours is ≥38%, for example, 38% - 50%, preferably 38% - 40%; the elongation at break after being heated at 60°C for 2 hours is ≥106%, for example, 106% - 110%.

[0027] According to an embodiment of the present invention, the soil temperature rise of the degradable composite film within one day is 3 - 10°C, for example, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C.

[0028] The present invention also provides a method for preparing a degradable composite film, the method comprising:

[0029] (1) Mixing materials: Mixing the raw materials for preparing the above composite material to obtain a mixture;

[0030] (2) Extruding and pelletizing: Extruding and plasticizing the mixture in step (1), and pelletizing the obtained melt;

[0031] (3) Blown film: Melting the pellets obtained in step (2), and blow - molding into a film to obtain the composite film.

[0032] According to an embodiment of the present invention, step (1) is specifically: Mixing the high - heat - radiation filler, the degradable polymer material and the additives to obtain a mixture. Specifically, mixing the graphene oxide solution, the degradable polymer material and the additives to obtain a mixture.

[0033] Preferably, after freeze - drying treatment of the graphene oxide solution, it is then mixed with the degradable polymer material and the additives.

[0034] Preferably, the temperature of the freeze - drying treatment is - 30 to - 50°C, for example, - 40°C. Preferably, the time of the freeze - drying treatment is 1 - 12 hours, for example, 1 hour.

[0035] According to an embodiment of the present invention, step (1) is carried out in a mixer.

[0036] Preferably, the stirring rate of the mixer is 100 - 500 r / min, and the stirring time is 0.5 - 5 hours, for example, 1 hour.

[0037] According to an embodiment of the present invention, in step (2), extrusion and plasticization are carried out in an extruder, and the temperature of the plasticization is 150 - 190°C, for example, 180°C.

[0038] According to an embodiment of the present invention, in step (2), the extruded melt is cooled and solidified by water cooling or air cooling to form solid drawbars, and the cooled drawbars are cut into particles by a pelletizer. Preferably, a vibrating screen can also be used to screen the cut particles to control the particle size and ensure the consistency of the particle size. Further, the sieved particles are dried (for example, first air-dried and then heat-dried) to remove the moisture on the surface of the modified particles, so as to facilitate subsequent processing and use.

[0039] According to an embodiment of the present invention, the time for the cooling and solidification is 1 - 10 hours, for example, 1 hour.

[0040] According to an embodiment of the present invention, the time for the screening is 1 - 10 hours, for example, 1 hour.

[0041] According to an embodiment of the present invention, the time for the drying is 1 - 10 hours, for example, 1 hour.

[0042] According to an embodiment of the present invention, the temperature for the air-drying is 20 - 30 °C, for example, 20 °C.

[0043] According to an embodiment of the present invention, the temperature for the heat-drying is 80 - 100 °C, for example, 90 °C.

[0044] According to an embodiment of the present invention, in step (3), the particles obtained in step (2) are heated and melted to form a uniform molten material, and are extruded into a film shape by a blown film machine screw. Preferably, compressed air is used to blow up the extruded tubular film to form the composite film. Further, the blown film is cooled by an air ring to quickly shape it. The cooled film is stretched by a traction device to adjust the thickness and width of the film and ensure the uniformity and consistency of the size. The traction-stretched film is wound into a roll for subsequent cutting and use.

[0045] According to an embodiment of the present invention, in step (3), the temperature of the melting is 150 - 190 °C, and examples are 150 °C, 160 °C, 170 °C or 180 °C.

[0046] According to an embodiment of the present invention, in step (3), the time for the blown film forming is 1 - 10 hours. Examples are 1 hour.

[0047] Beneficial effects

[0048] The graphene oxide in the composite material of the present invention has excellent characteristics such as a high specific surface area, a high content of hydrophilic groups such as hydroxyl and carboxyl groups, and an excellent thermal radiation emissivity, so that the structural strength and thermal radiation performance of the composite material are enhanced. Using the composite material in the composite film makes the composite film show more prominent application value.

[0049] In the composite film of the present invention, graphene oxide is used as a thermal radiation enhancer. Due to the large number of hydrophilic groups such as hydroxyl and carboxyl groups on the surface of graphene oxide, it can be bonded to the surface of the degradable polymer material through hydrogen bonding, increasing the structural strength and stability of the composite film. At the same time, the graphene oxide in the composite film can play a role in inhibiting bacteria in the soil, which is beneficial to the growth of crops and can further make full use of land resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a physical photograph of the high thermal radiation degradable composite film prepared according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative purposes to explain the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0052] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0053] Among them, in the preparation process of the high thermal radiation degradable composite material, taking self-made graphene oxide solution as an example for graphene oxide, a mixture of polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) as an example for the degradable polymer material, antioxidant 1010 as an example for the auxiliary agent; UV-928 as an example for the ultraviolet absorber; 622 as an example for the light stabilizer; ethylene bis-stearamide as an example for the dispersant.

[0054] The performance test process of each composite film in the following embodiments:

[0055] First, the degradable composite film is fully cooled and then its size is cut into 1000mm×280mm. The selected crop for testing is soybean, and the initial temperature is kept at 18°C and the relative humidity is kept at 60%. After the film is covered for 1 hour, the temperature and relative humidity data are measured and analyzed. The film tensile test is carried out in an electronic tensile testing machine, and finally the film elongation at break data is obtained. The film thermal radiation performance test is carried out in an infrared spectrometer, and finally the film thermal radiation emissivity data is obtained.

[0056] Example 1

[0057] A preparation method of a degradable composite film includes the following steps:

[0058] 1) Preparation of graphene oxide solution: According to patent document CN106587018B, use the high-frequency alternating current pulse method to prepare graphene oxide solution; First, put the anode of high-purity graphite with dimensions of 600mm×300mm×80mm and the high-purity graphite cathode plate into the electrolytic oxidation tank, and the distance between the anode and cathode plates is 70mm. Then pour 0.09% sulfuric acid electrolyte (i.e., 0.09% sulfuric acid aqueous solution) into the tank, turn on the power supply, and carry out electrolytic oxidation to prepare graphene aggregate sol. The anode and cathode plates are separated by a plastic mesh, and the effective current density is controlled at 100A / m 2 ; The power pulse frequency is 60Hz; The effective voltage is 20V; Control the temperature at 60°C. After reacting for 200 hours, when the concentration of graphene sol reaches 0.7%, the oxidation reaction ends, and the solution in the tank is the graphene oxide solution. The graphene oxide solution is freeze-dried at -40°C for 1 hour to obtain graphene oxide powder.

[0059] 2) Preparation of high-heat radiation degradable thin film material: 1. Mixing. Weigh 0.49945kg of PLA, 4.49505kg of PBAT, 0.5g of graphene oxide, and 5g of additives (the mass ratio of antioxidant 1010, ultraviolet absorber (UV-928), light stabilizer (622), and dispersant (vinyl bisstearamide) is 1:1:1:1), place them in a mixer, and stir at a speed of 300r / min for 1 hour to mix the particles and powders evenly.

[0060] 2. Extrusion: Put the mixed materials into the feeding hopper of the extruder, and set the temperature to 180°C to fully mix and plasticize all kinds of materials.

[0061] 3. Pelletizing: The extruded melt is cooled and solidified by water cooling for 1 hour to form a solid strip. The cooled strip is cut into particles of a certain size by a pelletizer after 1 hour. Use a vibrating screen to screen the cut particles to control the particle size and ensure the consistency of particle size. The sieved particles are first air-dried at 20°C and then heat-dried at 90°C to remove the moisture on the surface of the modified particles for subsequent processing and use.

[0062] 4. Film blowing: Heat and melt the particles obtained in step 3 at 180°C to form a uniform molten material, and extrude it into a film shape through the screw of the film blowing machine. During this process, use compressed air to blow up the extruded tubular film to form a film with a certain thickness and width. The blown film is cooled by an air ring for 1 hour to quickly shape it. The cooled film is stretched by a traction device to adjust the film thickness to 0.01mm and the width to 280mm to ensure the uniformity and consistency of the size. The traction-stretched film is wound into a roll for subsequent cutting and use.

[0063] Comparative Example 1

[0064] The preparation method of Comparative Example 1 was the same as that of Example 1, except that graphene oxide was not added.

[0065] Example 2

[0066] A preparation method of a degradable composite film, comprising the following steps:

[0067] 1) Preparation of graphene oxide solution: The preparation of the graphene oxide solution was the same as that in Example 1.

[0068] 2) Preparation of the high heat radiation degradable film material: 1. Mixing materials. Weigh 0.49935 kg of PLA, 4.49415 kg of PBAT, 1.5 g of graphene oxide, and 5 g of additives (antioxidant (1010), ultraviolet absorber (UV-928), light stabilizer (622), and dispersant (ethylene bisstearamide) with a mass ratio of 1:1:1:1), place them in a mixer, and stir at a speed of 300 r / min for 1 hour to uniformly mix the particles and powders.

[0069] 2. Extrusion: Place the mixed materials in the feeding hopper of the extruder, set the temperature to 180 °C, and fully mix and plasticize all kinds of materials.

[0070] 3. Pelletizing: Cool and solidify the extruded melt by water cooling for 1 hour to form a solid drawbar. The cooled drawbar is cut into particles of a certain size by a pelletizer after 1 hour. Use a vibrating screen to screen the cut particles to control the particle size and ensure the consistency of the particle size. The sieved particles are first air-dried at 20 °C and then heat-dried at 90 °C to remove the moisture on the surface of the modified particles for subsequent processing and use.

[0071] 4. Blown film: Heat and melt the particles obtained in step 3 at 180 °C to form a uniform molten material, and extrude it into a film shape through the screw of the blown film machine. During this process, use compressed air to blow up the extruded tubular film to form a film with a certain thickness and width. The blown film is cooled by an air ring for 1 hour to quickly set the shape. The cooled film is stretched by a traction device to adjust the film thickness to 0.01 mm and the width to 280 mm to ensure the uniformity and consistency of the size. The traction-stretched film is wound into a roll for subsequent cutting and use.

[0072] Example 3

[0073] A preparation method of a degradable composite film, comprising the following steps:

[0074] 1) Preparation of graphene oxide solution: The preparation of the graphene oxide solution was the same as that in Example 1.

[0075] 2) Preparation of high heat radiation degradable thin film material: 1. Mixing materials. Weigh 0.49925 kg of PLA, 4.49325 kg of PBAT, 2.5 g of graphene oxide, and 5 g of additives (the mass ratio of antioxidant (1010), ultraviolet absorber (UV-928), light stabilizer (622), and dispersant (vinyl bisstearamide) is 1:1:1:1). Place them in a mixer and stir at a speed of 300 r / min for 1 hour to evenly mix the particles and powders.

[0076] 2. Extrusion: Place the mixed materials in the feeding hopper of the extruder, set the temperature to 180 °C, and fully mix and plasticize all kinds of materials.

[0077] 3. Pelletizing: Cool and solidify the extruded melt by water cooling for 1 hour to form solid strips. Cut the cooled strips into particles of a certain size by a pelletizer for 1 hour. Use a vibrating screen to screen the cut particles to control the particle size and ensure the consistency of particle size. Air-dry the sieved particles at 20 °C first and then heat-dry them at 90 °C to remove the moisture on the surface of the modified particles for subsequent processing and use.

[0078] 4. Film blowing: Heat and melt the composite material particles at 180 °C to form a uniform molten material, and extrude it into a film shape through the screw of the film blowing machine. During this process, use compressed air to blow up the extruded tubular film to form a film with a certain thickness and width. Cool the blown film through an air ring for 1 hour for rapid shaping. Stretch the cooled film through a traction device, adjust the film thickness to 0.01 mm and the width to 280 mm to ensure the uniformity and consistency of the size. The traction-stretched film is wound into a roll for subsequent cutting and use.

[0079] Example 4

[0080] A preparation method of a degradable composite film, comprising the following steps:

[0081] 1) Preparation of graphene oxide solution: The preparation of the graphene oxide solution is the same as that in Example 1.

[0082] 2) Preparation of high heat radiation degradable thin film material: 1. Mixing materials. Weigh 0.499 kg of PLA, 4.491 kg of PBAT, 5 g of graphene oxide, and 5 g of additives (the mass ratio of antioxidant (1010), ultraviolet absorber (UV-928), light stabilizer (622), and dispersant (vinyl bisstearamide) is 1:1:1:1). Place them in a mixer and stir at a speed of 300 r / min for 1 hour to evenly mix the particles and powders.

[0083] 2. Extrusion: Place the mixed materials in the feeding hopper of the extruder, set the temperature to 180 °C, and fully mix and plasticize all kinds of materials.

[0084] 3. Granulation: The extruded melt is cooled and solidified by water cooling for 1 hour to form solid strands. The cooled strands are cut into particles of a certain size by a pelletizer over 1 hour. A vibrating screen is used to screen the cut particles to control the particle size and ensure the consistency of the particle size. The screened particles are first air-dried at 20°C and then heat-dried at 90°C to remove the moisture on the surface of the modified particles for subsequent processing and use.

[0085] 4. Film Blowing: The composite material particles are heated and melted at 180°C to form a uniform molten material, and are extruded into a film shape through the screw of a film blowing machine. During this process, compressed air is used to blow up the extruded tubular film to form a film with a certain thickness and width. The blown film is cooled by an air ring for 1 hour for rapid shaping. The cooled film is stretched by a traction device, and the film thickness is adjusted to 0.01 mm and the width to 280 mm to ensure the uniformity and consistency of the dimensions. The traction-stretched film is wound into a roll for subsequent cutting and use.

[0086] Test Example 1

[0087] The degradable composite films of Examples 1-4 and the composite film of Comparative Example 1 were used to improve the temperature and relative humidity of the soybean growth environment, and their performance was tested. At the same time, the tensile properties and thermal radiation properties of the films were tested.

[0088] When using the degradable composite film of Comparative Example 1, the temperature of the soybean plant growth environment increased by 2°C within a day; the relative humidity increased by 5%; the degradable composite film of Comparative Example 1 was subjected to a tensile test after being frozen at -20°C for 2 hours, and the elongation at break was 37%; and it was subjected to a tensile test after being heated at 60°C for 2 hours, and the elongation at break was 105%. The thermal radiation emissivity of the degradable composite film of Comparative Example 1 was 0.28.

[0089] Compared with Comparative Example 1, when using the degradable composite film of Example 1, the temperature of the soybean plant growth environment increased by 5°C within a day; the relative humidity increased by 8%; the high-thermal-radiation degradable composite film of Example 1 was subjected to a tensile test after being frozen at -20°C for 2 hours, and the elongation at break was 39%; and it was subjected to a tensile test after being heated at 60°C for 2 hours, and the elongation at break was 106%. The thermal radiation emissivity of the high-thermal-radiation degradable composite film of Example 1 was 0.90.

[0090] Compared with Comparative Example 1, when using the degradable composite film of Example 2, the temperature of the soybean plant growth environment increased by 10°C within a day; the relative humidity increased by 12%; the high-thermal-radiation degradable composite film of Example 2 was subjected to a tensile test after being frozen at -20°C for 2 hours, and the elongation at break was 40%; and it was subjected to a tensile test after being heated at 60°C for 2 hours, and the elongation at break was 108%. The thermal radiation emissivity of the high-thermal-radiation degradable composite film of Example 2 was 0.95.

[0091] Compared with Comparative Example 1, when using the degradable composite film of Example 3, the temperature of the growth environment of soybean plants increases by 9 °C within one day; the relative humidity increases by 10%; the high heat radiation degradable composite film of Example 3 is frozen at -20 °C for 2 hours for a tensile test, and the elongation at break is 39%; when heated at 60 °C for 2 hours for a tensile test, the elongation at break is 107%. The heat radiation emissivity of the high heat radiation degradable composite film of Example 3 is 0.91.

[0092] Compared with Comparative Example 1, when using the degradable composite film material of Example 4, the temperature of the growth environment of soybean plants increases by 8 °C within one day; the relative humidity increases by 9%; the high heat radiation degradable composite film material of Example 4 is frozen at -20 °C for 2 hours for a tensile test, and the elongation at break is 38%; when heated at 60 °C for 2 hours for a tensile test, the elongation at break is 106%. The heat radiation emissivity of the high heat radiation degradable composite film of Example 4 is 0.92.

[0093] According to the adjustment of the process parameters recorded in the present invention, the preparation of the high heat radiation degradable composite film can be achieved, and it exhibits basically the same performance as the composite film of Example 2.

[0094] Above, the embodiments of the present invention have been described by way of example. However, the protection scope of the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A degradable composite material, characterized in that: The raw materials for preparing the composite material include high thermal radiation filler Degradable polymer materials 99.4%-99.9945% and additives 2. The composite material according to claim 1, characterized in that The high thermal radiation filler is graphene oxide. Preferably, the degradable polymer material is selected from at least two of polylactic acid, polybutylene adipate-terephthalate, and polyvinyl alcohol. Preferably, the auxiliary agent comprises at least one of an antioxidant, an ultraviolet absorber, a light stabilizer and a dispersant.

3. The method for preparing the composite material according to claim 1 or 2, characterized in that: The preparation method comprises: mixing the raw materials for preparing the composite material to obtain the composite material.

4. A degradable composite film, which is a film of the composite material according to claim 1 or 2.

5. The composite film according to claim 4, characterized in that: The thermal emissivity of the degradable composite film is 0.90-0.

95. Preferably, the thickness of the degradable composite film is 0.01-0.015 mm. Preferably, the color of the degradable composite film is black. Preferably, the elongation at break of the degradable composite film after being frozen at -20°C for 2 hours is ≥38%; and the elongation at break after being heated at 60°C for 2 hours is ≥106%. Preferably, the soil temperature rise of the degradable composite film within one day is 3-10°C.

6. The method for preparing the composite film according to claim 4 or 5, characterized in that: The method comprises: (1) Mixing: mixing the raw materials for preparing the composite material to obtain a mixture; (2) extrusion and granulation: extruding and plasticizing the mixture in step (1), and granulating the obtained melt; (3) Film blowing: The particles obtained in step (2) are melted and blown into a film to obtain the composite film.

7. The method according to claim 6, characterized in that In step (1), the graphene oxide solution is freeze-dried and then mixed with the degradable polymer material and the additive. Preferably, the freeze-drying treatment temperature is -30 to -50°C, and the freeze-drying treatment time is 1 to 12 hours.

8. The method according to claim 6, characterized in that In step (2), extrusion plasticization is carried out in an extruder, and the plasticization temperature is 150-190°C.

9. The method according to claim 6, characterized in that In step (3), the melting temperature is 150-190° C.; in step (3), the film blowing time is 1-10 hours.

10. Use of the composite material according to claim 1 or 2 or the degradable composite film according to claim 4 or 5 in the field of agriculture.

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