Easily degradable flexible transparent film and preparation method and application thereof

Abstract

The invention provides an easy-to-degrade flexible transparent film and a preparation method and application thereof, and the preparation method comprises the following steps: step (1) destroying the structure of waste cotton cloth or waste cotton fibers by using a chemical reagent, and decomposing the waste cotton cloth or waste cotton into nano-sized fibers; (2) cleaning the obtained nano-sized fibers, and dispersing the nano-sized fibers in an aqueous solution to obtain a nano-sized fiber dispersion liquid; and (3) assembling the obtained nano-sized fiber dispersion liquid into the flexible transparent film which is easy to degrade and can be repaired by water. The film disclosed by the invention can be naturally degraded in soil, is pollution-free, can be automatically bonded together at broken or damaged parts under water wetting, realizes self-repairing, and also has high transparency. The easily degradable flexible transparent film can be used in the field of green packaging materials, can also be used as a substrate to construct a flexible circuit and a flexible display device, and is applied in the field of green flexible electronics. Compared with a plastic film which is difficult to degrade and repair, the film has great advantages.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to an easily degradable flexible transparent film, a preparation method thereof, and an application thereof. Background Art

[0002] Plastic films are widely used in fields such as packaging materials and flexible electronics. However, with the increasing use of plastic films, the environmental problems they bring are becoming increasingly serious. Many traditional plastic films are difficult to degrade, such as polyethylene terephthalate films (PET), polyimide films (PI), polycarbonate (PC), etc., which will cause environmental pollution and bring great pressure to the ecosystem. In addition, plastic films are not easy to repair when damaged and are discarded, resulting in a greatly shortened service life and increasing the risk of resource waste. Developing films with self-healing capabilities and repair strategies can extend the service life of materials and achieve efficient and sustainable utilization of resources. Synthetic polymers are often used to construct films with repair capabilities, and these synthetic polymers usually have poor biodegradability and biocompatibility. In addition, such films often need to be repaired under conditions such as heating, electric fields, mechanical forces, ultraviolet light irradiation, or adding chemical reagents, which limit their application scope. An economical and fast repair method provides an ideal way to extend the service life of materials and optimize economic benefits, and expands the application of films in fields such as electronics, medical use, and flexible energy storage devices. Therefore, it is of great significance to develop a green and environmentally friendly flexible transparent film that is easily degradable and easily repairable. Summary of the Invention

[0003] Aiming at the above technical problems, the present invention provides an easily degradable flexible transparent film. The present invention uses waste cotton cloth or waste cotton as raw materials to develop a green and environmentally friendly flexible transparent film that is easily degradable and water-repairable. The degradable and water-repairable flexible transparent film developed by the present invention has broad application prospects in the fields of green packaging materials and flexible electronics, etc., has important practical value, and also provides an idea and method for the high-value utilization of cotton waste / abandoned cotton textiles.

[0004] Another object of the present invention is to provide a preparation method of the easily degradable flexible transparent film.

[0005] Another object of the present invention is to provide an application of the easily degradable flexible transparent film in the fields of green packaging materials and flexible electronics, etc. The present invention has developed a method for constructing flexible circuits and flexible display devices using this film as a matrix.

[0006] Note that the recording of these objects does not prevent the existence of other objects. One embodiment of the present invention does not need to achieve all the above objects. Other objects than the above objects can be extracted from the descriptions of the specification, drawings, and claims.

[0007] The present invention achieves the above technical objectives through the following technical means.

[0008] A method for preparing an easily degradable flexible transparent film, comprising the following steps:

[0009] Step (1): Using chemical reagents to destroy the structure of waste cotton cloth or waste cotton fibers, and decomposing the waste cotton cloth or waste cotton into nanofibers.

[0010] Step (2): After washing the nanofibers obtained in step (1), dispersing them in an aqueous solution to obtain a nanofiber dispersion.

[0011] Step (3): Assembling the nanofiber dispersion obtained in step (2) into an easily degradable flexible transparent film, and the easily degradable flexible transparent film has the properties of easy degradation and water repairability.

[0012] In the above solution, in step (1), the chemical reagent is TEMPO / NaBr / NaClO / NaOH chemical reagent, including 2,2,6,6-tetramethylpyridine-1-oxyl radical TEMPO, sodium bromide NaBr, sodium hypochlorite NaClO, and sodium hydroxide NaOH.

[0013] Further, step (1) is specifically:

[0014] Breaking the waste cotton cloth or waste cotton with a wall breaker in an aqueous solution, and using TEMPO / NaBr / NaClO / NaOH chemical reagent to carry out structure modification treatment on the broken waste cotton cloth or waste cotton in deionized water, and decomposing the waste cotton cloth or waste cotton into nanofibers.

[0015] The mass ratio of deionized water, waste cotton cloth or waste cotton, 2,2,6,6-tetramethylpyridine-1-oxyl radical TEMPO, sodium bromide NaBr, and sodium hypochlorite NaClO is (2 - 15):(0.04 - 0.24):(0.002 - 0.003):(0.02 - 0.03):1; NaOH is used to adjust the pH value of the solution during the structure modification process to make it between 9 and 11. Under these parameter conditions, the chemical reagent can effectively remove components such as pigments, waxes, proteins, and pectins on the surface of waste cotton cloth or waste cotton fibers, and at the same time oxidize the primary hydroxyl groups on the molecular chains of waste cotton cloth or waste cotton fibers into carboxyl groups, and destroy the hydrogen bond network between the molecular chains of waste cotton cloth or waste cotton fibers.

[0016] Further, in step (3), the assembly method is suction filtration, natural drying, drying, hot pressing, or spin coating.

[0017] A degradable flexible transparent film, prepared according to the preparation method of the degradable flexible transparent film, the degradability of the degradable flexible transparent film is manifested in that this film can be naturally degraded in the soil and has no pollution to the environment.

[0018] Furthermore, the degradable flexible transparent film also has water-repairability, and the water-repairability is manifested in that when water is dropped at the disconnected or damaged part of the film and naturally dried, the disconnected or damaged part of the film can be automatically bonded together to achieve self-repair of the film.

[0019] Furthermore, the degradable flexible transparent film has good transparency.

[0020] An application of the above-mentioned degradable flexible transparent film in green packaging materials or green flexible electronics.

[0021] Using the degradable flexible transparent film as a substrate to construct green flexible electronics, and the green flexible electronics are flexible circuits or flexible display devices.

[0022] Furthermore, it includes the following steps:

[0023] Step (1) Print a silver circuit on the degradable flexible transparent film;

[0024] Step (2) Install an LED lamp and / or a chip, a filter capacitor, a starting capacitor, and a crystal oscillator on the printed silver circuit.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The present invention uses waste cotton cloth or waste cotton as raw materials, uses chemical reagents to destroy the structure of the waste cotton cloth or waste cotton fibers, decomposes them into nano-sized fibers, and then assembles the obtained nano-sized fibers into a film to obtain a degradable and water-repairable flexible transparent film. This film made of waste cotton cloth can be naturally degraded in the soil without pollution; when this film is wetted with water, the disconnected or damaged parts can be automatically bonded together to achieve self-repair of the film; this film also has high transparency. The degradable and water-repairable flexible transparent film developed by the present invention can be used in the field of green packaging materials; this film can also be used as a substrate to construct flexible circuits and flexible display devices, and explore the application of this film in fields such as green flexible electronics. This film has great advantages compared with plastic films that are difficult to degrade and not easy to repair.

[0027] Note that the recording of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above can be obviously seen and extracted from the descriptions in the specification, drawings, claims, etc. Description of the Drawings

[0028] Figure 1Schematic diagram of the easily degradable flexible transparent film prepared in Example 1 of the present invention. Among them, Figure 1 (a) is a photo of waste cotton cloth; Figure 1 (b) is the easily degradable flexible transparent film prepared from waste cotton cloth; Figure 1 (c) is a photo of the film being bent; Figure 1 (d) is a photo of the film with weights hanging;

[0029] Figure 2 Schematic diagram showing the damaged film prepared from waste cotton cloth repaired with water in Example 1 of the present invention. Among them, Figure 2 (a) is the damaged and disconnected film, Figure 2 (b) is the damaged film wetted with water, Figure 2 (c) is the film after natural drying and completed repair, Figure 2 (d) is the repaired film with a 200 g weight hanging;

[0030] Figure 3 Schematic diagram of the easily degradable flexible transparent film prepared in Example 5 of the present invention. Among them, Figure 3 (a) is the prepared easily degradable flexible transparent film; Figure 3 (b) is a photo of the film being bent; Figure 3 (c) is a photo of the film with weights hanging;

[0031] Figure 4 Schematic diagram showing the degradability of the easily degradable flexible transparent film prepared in Example 5 of the present invention. Among them, Figure 4 (a) is the 0th day when the easily degradable flexible transparent film is buried in the soil, Figure 4 (b) is the 30th day, Figure 4 (c) is the 45th day, Figure 4 (d) is the 60th day;

[0032] Figure 5 Schematic diagram showing the damaged film prepared in Example 5 repaired with water. Among them, Figure 5 (a) is the damaged and disconnected film, Figure 5 (b) is the damaged film wetted with water, Figure 5 (c) is the film after natural drying and completed repair, Figure 5 (d) is the repaired film with a 200 g weight hanging;

[0033] Figure 6 Schematic diagram of the film product prepared in Example 5 of the present invention used to construct a flexible circuit device. Among them, Figure 6 (a) is the flexible circuit device constructed with the film, Figure 6 (b) is the LED light of the flexible circuit device being lit, Figure 6 (c) is that the flexible circuit device can still work normally in the bent state;

[0034] Figure 7 FIG. 2 is a schematic diagram of using the thin film product prepared in Example 5 of the present invention to construct a flexible display device. Among them, Figure 7 (a) is a flexible display device constructed using the thin film; Figure 7 (b)- Figure 7 (g) are for the LED lights of the display device being lit, successively displaying COTTON. Detailed implementation manners

[0035] The embodiments of the present invention will be described in detail below. The embodiments described by referring to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.

[0036] Example 1

[0037] A preparation method of a degradable flexible transparent thin film includes the following steps:

[0038] Step 1) Break the waste cotton cloth in an aqueous solution with a wall breaker;

[0039] Step 2) Add the waste cotton cloth broken in Step 1), NaBr solution, and TEMPO solution into deionized water, start the stirrer to mix them evenly, and then slowly dropwise add NaClO solution. During the reaction process, adjust the pH of the solution with 3M NaOH to maintain the pH between 9 and 11. Among them, the mass ratio of deionized water, waste cotton cloth, TEMPO, NaBr, and NaClO is 3.5:0.06:0.0025:0.0275:1 to obtain nanofibers;

[0040] Step 3) After washing the nanofibers obtained in Step 2), disperse them in an aqueous solution to obtain a nanofiber dispersion;

[0041] Step 4) Assemble the nanofiber dispersion obtained in Step 3) into a degradable flexible transparent thin film by vacuum filtration. This film has degradability and water reparability.

[0042] Figure 1 FIG. 3 shows the degradable and water-reparable flexible transparent thin film prepared from waste cotton cloth in Example 1. Among them, Figure 1 (a) is a photo of the waste cotton cloth; Figure 1 (b) is the degradable flexible transparent thin film prepared from waste cotton cloth, showing good transparency; Figure 1 (c) is a bending photo of the thin film, showing good flexibility; Figure 1 (d) is a photo of the thin film hanging weights. The 1.5 cm wide thin film can hang 200 g weights, and the thin film shows good mechanical properties.

[0043] Example 2

[0044] A preparation method of an easily degradable flexible transparent film, comprising the following steps: Step 1) Break waste cotton cloth in an aqueous solution with a wall breaker;

[0045] Step 2) Add the waste cotton cloth broken in Step 1, NaBr solution, and TEMPO solution into deionized water, start a stirrer to mix them evenly, then slowly dropwise add NaClO solution, and adjust the pH of the solution with 3M NaOH during the reaction to keep the pH between 9 and 11. Among them, the mass ratio of deionized water, waste cotton cloth, TEMPO, NaBr, and NaClO is 2.33:0.04:0.002:0.02:1 to obtain nanofibers;

[0046] Step 3) After washing the nanofibers obtained in Step 2, disperse them in an aqueous solution to obtain a nanofiber dispersion;

[0047] Step 4) Assemble the nanofiber dispersion obtained in Step 3 into an easily degradable flexible transparent film by vacuum filtration. This film has the properties of easy degradation and water repairability.

[0048] Example 3

[0049] A preparation method of an easily degradable flexible transparent film, comprising the following steps:

[0050] Step 1) Break waste cotton cloth in an aqueous solution with a wall breaker.

[0051] Step 2) Add the waste cotton cloth broken in Step 1, NaBr solution, and TEMPO solution into deionized water, start a stirrer to mix them evenly, then slowly dropwise add NaClO solution, and adjust the pH of the solution with 3M NaOH during the reaction to keep the pH between 9 and 11. Among them, the mass ratio of deionized water, waste cotton cloth, TEMPO, NaBr, and NaClO is 2.33:0.04:0.0025:0.0275:1 to obtain nanofibers;

[0052] Step 3) After washing the nanofibers obtained in Step 2, disperse them in an aqueous solution to obtain a nanofiber dispersion;

[0053] Step 4) Assemble the nanofiber dispersion obtained in Step 3 into an easily degradable flexible transparent film by vacuum filtration. This film has the properties of easy degradation and water repairability.

[0054] Example 4

[0055] Use the easily degradable flexible transparent film prepared in Example 1 to demonstrate the water repairability of the film and repair the damaged film:

[0056] Step 1) Place the damaged and disconnected film together;

[0057] Step 2) Moisten the film with water;

[0058] Step 3) After natural drying, the disconnected film fuses together again, completing the repair of the damaged film.

[0059] Figure 2 An example of repairing a damaged film with water is shown. Figure 2 (a) The damaged and disconnected film; Figure 2 (b) Place the damaged and disconnected film together and moisten it with water; Figure 2 (c) After natural drying, the disconnected film fuses together again; Figure 2 (d) After repair, a 200 g weight can still be hung, and the repaired part of the film can be firmly connected together, indicating that the film has good water-repairable characteristics.

[0060] Example 5

[0061] A preparation method of a degradable flexible transparent film includes the following steps:

[0062] Step 1) Break the waste cotton in an aqueous solution with a wall breaker.

[0063] Step 2) Add the waste cotton broken in Step 1), NaBr solution, and TEMPO solution to deionized water, start the stirrer to mix them evenly, and then slowly dropwise add NaClO solution. During the reaction, adjust the pH of the solution with 3M NaOH to keep the pH between 9 and 11. Among them, the mass ratio of deionized water, waste cotton, TEMPO, NaBr, and NaClO is 7:0.12:0.002:0.02:1 to obtain nanofibers;

[0064] Step 3) After washing the nanofibers obtained in Step 2), disperse them in an aqueous solution to obtain a nanofiber dispersion;

[0065] Step 4) Assemble the nanofiber dispersion obtained in Step 3) into a degradable flexible transparent film by vacuum filtration. This film has the properties of being degradable and water-repairable.

[0066] Figure 3 An example of a degradable and water-repairable flexible transparent film prepared from waste cotton in Example 5 is shown. Figure 3 In (a) is the degradable flexible transparent film prepared in Example 5, showing good transparency; Figure 3 (b) The bending photo of the film, showing good flexibility; Figure 3 (c) The photo of the film hanging a weight. A 1.5 cm wide film can hang a 200 g weight, indicating that the film shows good mechanical properties.

[0067] Figure 4 It shows the degradability of the easily degradable flexible transparent film prepared in Example 5. The depth of the film buried in the soil is about 3 cm. Figure 4 (a) is the 0th day when the film is buried in the soil, Figure 4 (b) is the 30th day when the film is buried in the soil, Figure 4 (c) is the 45th day when the film is buried in the soil, Figure 4 (d) is the 60th day when the film is buried in the soil. On the 45th day after being buried in the soil, most of the film has degraded. On the 60th day after being buried in the soil, the film has basically degraded completely, indicating that the film has good degradability.

[0068] Example 6

[0069] A preparation method of an easily degradable flexible transparent film, comprising the following steps:

[0070] Step 1) Break the waste cotton in an aqueous solution with a wall breaker;

[0071] Step 2) Add the waste cotton broken in Step 1), NaBr solution, and TEMPO solution to deionized water, start the stirrer to mix them evenly, and then slowly dropwise add NaClO solution. During the reaction process, adjust the pH of the solution with 3M NaOH to keep the pH between 9 and 11. Among them, the mass ratio of deionized water, waste cotton, TEMPO, NaBr, and NaClO is 3.5:0.06:0.002:0.02:1 to obtain nanofibers;

[0072] Step 3) After washing the nanofibers obtained in Step 2), disperse them in an aqueous solution to obtain a nanofiber dispersion;

[0073] Step 4) Assemble the nanofiber dispersion obtained in Step 3) into an easily degradable flexible transparent film by vacuum filtration. This film has the properties of easy degradation and water repairability.

[0074] Example 7

[0075] Using the easily degradable flexible transparent film prepared in Example 5 to demonstrate the water-repairable characteristics of the film and repair the damaged film:

[0076] Step 1) Place the damaged and disconnected films together;

[0077] Step 2) Moisten the film with water;

[0078] Step 3) After natural drying, the disconnected films are re-fused together to complete the repair of the damaged film.

[0079] Figure 5Shows an example of using water to repair a damaged thin film. Figure 5 (a) is a damaged and disconnected thin film; Figure 5 (b) Place the damaged and disconnected thin films together and moisten them with water; Figure 5 (c) After natural drying, the disconnected thin films fuse together again; Figure 5 (d) After repair, a 200g weight can still be hung, and the repaired part of the thin film can be firmly connected together, indicating that the thin film has good water-repairable characteristics.

[0080] Example 8

[0081] Use the degradable flexible transparent thin film product prepared in Example 5 for the application of constructing flexible circuit devices. The specific steps are as follows:

[0082] (1) Print silver circuits on this thin film;

[0083] (2) Install LED lights on the printed circuits to prepare flexible circuit devices.

[0084] Figure 6 Shows an example of using the thin film product prepared in Example 5 for constructing flexible circuit devices. Figure 6 In (a) is a flexible circuit device constructed using the thin film; Figure 6 (b) shows the LED light of the flexible circuit device being lit; Figure 6 (c) shows that the flexible circuit device can still work normally in a bent state. It can be seen that this thin film can be used as a substrate to construct flexible circuits and has good flexibility.

[0085] Example 9

[0086] Use the degradable flexible transparent thin film product prepared in Example 5 for the application of constructing flexible display devices. The specific steps are as follows:

[0087] (1) Print a 6x6 array of silver circuits on this thin film, and isolate the overlapping parts of the horizontal and vertical circuits with a PDMS insulating layer;

[0088] (2) Install LED lights, chips, filter capacitors, oscillating capacitors, and crystal oscillators on the printed circuits to prepare flexible display devices;

[0089] Figure 7 Shows an example of using the thin film product prepared in Example 5 for constructing flexible display devices. Figure 7 (a) is a flexible display device constructed using the thin film; Figure 7 (b)- Figure 7 (g) shows that the LED lights of the display device are lit, and the word "COTTON" is displayed in sequence. It can be seen that this thin film can be used as a substrate to construct flexible display devices.

[0090] It should be understood that although this specification is described according to various embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0091] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a degradable flexible transparent film, characterized in that: The steps include: Step (1) using chemical reagents to destroy the structure of waste cotton fabric or waste cotton fibers, thereby decomposing the waste cotton fabric or waste cotton into nano-sized fibers; Step (2) dispersing the nanometer-sized fibers obtained in step (1) in an aqueous solution to obtain a nanometer-sized fiber dispersion; Step (3) assembles the nano-sized fiber dispersion obtained in step (2) into an easily degradable flexible transparent film, wherein the easily degradable flexible transparent film is easily degradable and water-repairable.

2. The method for preparing the easily degradable flexible transparent film according to claim 1, characterized in that: In the step (1), the chemical reagents include 2,2,6,6-tetramethylpyridine-1-oxyl free radical TEMPO, sodium bromide NaBr, sodium hypochlorite NaClO and sodium hydroxide NaOH.

3. The method for preparing the easily degradable flexible transparent film according to claim 2, characterized in that: In the step (1), the structure of the waste cotton cloth or waste cotton fiber is destroyed by using the chemical reagent to remove the pigment, wax, protein and pectin components on the surface of the waste cotton cloth or waste cotton fiber, and at the same time oxidizing the primary hydroxyl groups on the molecular chains of the waste cotton cloth or waste cotton fiber to carboxyl groups, thereby destroying the hydrogen bond network between the molecular chains of the waste cotton cloth or waste cotton fiber.

4. The method for preparing the easily degradable flexible transparent film according to claim 3, characterized in that: The step (1) is specifically: The waste cotton cloth or waste cotton is broken into pieces in an aqueous solution, and the broken waste cotton cloth or waste cotton is subjected to a structural modification treatment using the chemical reagent in deionized water to decompose the waste cotton cloth or waste cotton into nano-sized fibers; The mass ratio of deionized water, waste cotton cloth or waste cotton, 2,2,6,6-tetramethylpyridine-1-oxyl free radical TEMPO, sodium bromide NaBr, and sodium hypochlorite NaClO is (2-15): (0.04-0.24): (0.002-0.003): (0.02-0.03): 1; NaOH is used to adjust the pH value of the solution in the process of structural modification to be between 9 and 11.

5. The method for preparing the easily degradable flexible transparent film according to claim 1, characterized in that: In the step (3), the assembly method is suction filtration, natural drying, baking, hot pressing or spin coating.

6. A degradable flexible transparent film, characterized in that: The degradable flexible transparent film is prepared by the method for preparing the degradable flexible transparent film according to any one of claims 1 to 5, wherein the degradability of the degradable flexible transparent film is manifested in that the film can be naturally degraded in the soil and does not pollute the environment.

7. The easily degradable flexible transparent film according to claim 6, characterized in that: The easily degradable flexible transparent film is also water-repairable, and the water-repairability is manifested in that after dripping water on the broken or damaged part of the film and naturally drying, the broken or damaged part of the film can automatically bond together, thereby achieving self-repair of the film.

8. Application of the easily degradable flexible transparent film according to claim 6 or 7 in green packaging materials or green flexible electronics.

9. The use according to claim 8, characterized in that: Green flexible electronics are constructed using an easily degradable flexible transparent film as a substrate, wherein the green flexible electronics are flexible circuits or flexible display devices.

10. The use according to claim 9, characterized in that: The following steps are involved: Step (1) printing a silver circuit on the degradable flexible transparent film; Step (2) Installing LED lamps and / or chips, filter capacitors, oscillator capacitors, and crystal oscillators on the printed silver circuit.

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