Highly efficient photothermal responsive polylactic acid fiber and nonwoven material and preparation method thereof

Abstract

This invention discloses a high-efficiency photothermal responsive polylactic acid (PLA) fiber and nonwoven material, and its preparation method, belonging to the field of photostimulation-responsive smart materials and their preparation. The preparation method involves first melt-blending and granulating polyvinyl acetate (PVC) and zirconium carbide nanoparticles, then melt-granulating PLA with PVC / PVC / zirconia nanoparticle chips to obtain PLA / PVC / zirconia nanoparticle chips. High-efficiency photothermal responsive PLA fibers are obtained through melt spinning, drawing, and heat setting; and high-efficiency photothermal responsive and shape-memory PLA nonwoven materials are obtained through spunbonding. This invention achieves high-efficiency photothermal responsive PLA fibers and high-efficiency photothermal responsive and shape-memory PLA spunbond nonwoven materials with good mechanical properties and photothermal effects by adjusting spinning process parameters, zirconium carbide content, and PVC content.

Description

Technical Field

[0001] This invention belongs to the field of photostimulation-responsive smart materials and their preparation, specifically involving a highly efficient photothermal responsive polylactic acid fiber and nonwoven material and its preparation method. Background Technology

[0002] With the development of human society, the use of biodegradable and renewable polylactic acid (PLA) materials as alternatives to traditional petroleum-based materials has become a research hotspot. However, PLA materials require functional modification to meet current societal demands for material functional properties. One effective method for this is to blend PLA materials with functional materials to create PLA-based functional materials. With the development of smart technology, smart materials have become one of the most promising materials for research in the field of functional materials. To apply PLA materials to the field of smart materials, replacing certain traditional petroleum-based functional materials, alleviating the pressure on non-renewable resources, and reducing environmental pollution, PLA smart materials have become a research focus.

[0003] Polylactic acid (PLA) smart materials refer to materials whose properties can change under external stimuli, such as temperature, humidity, ultraviolet radiation, electric and magnetic fields, and mechanical forces. Currently, research on PLA-based smart materials focuses primarily on photostimulation-temperature responsive and photo- or temperature-stimulated shape memory responsive materials. However, most of these materials are currently in sheet form, which limits their flexibility in practical applications. Fiber or woven fabric forms, on the other hand, offer significant flexibility in practical applications. Currently, research on the preparation of photostimulation-responsive PLA fibers or nonwoven materials is lacking. In PLA functional materials, the dispersion of functional materials within the PLA matrix is ​​poor. Therefore, developing highly efficient photothermal responsive PLA fibers and nonwoven materials to expand the application areas of biodegradable PLA, while simultaneously improving the dispersion of nanomaterials within the matrix of PLA functional materials, is also a pressing issue that needs to be addressed in this field. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a high-efficiency photothermal responsive polylactic acid fiber and nonwoven material and its preparation method.

[0005] This invention provides a high-efficiency photothermal responsive polylactic acid fiber and nonwoven material and its preparation method. The substrate is a mixture of polylactic acid and polyvinyl acetate, and the photothermal responsive functional material is nano-zirconium carbide.

[0006] As a preferred embodiment of the high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention, wherein the mass ratio of polylactic acid to polyvinyl acetate in the substrate is (99-90):(1-10), and polyvinyl acetate can improve the dispersion of functional material nano-zirconium carbide in the polylactic acid matrix.

[0007] As a preferred embodiment of the high-efficiency photothermal responsive polylactic acid material of the present invention, wherein: nano-zirconium carbide accounts for 0.01 to 3% of the weight of the fiber or nonwoven material.

[0008] As a preferred embodiment of the high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention, wherein: the viscosity-average molecular weight of polylactic acid is 1.0 × 10⁻⁶. 4 ~2.0×10 6 .

[0009] As a preferred embodiment of the high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention, wherein the photostimulation responsive functional material is nano-zirconium carbide with a particle size of 10-500 nm.

[0010] This invention provides a method for preparing high-efficiency photothermal responsive polylactic acid-based chips, comprising the following steps:

[0011] Step 1: Polyvinyl acetate and nano-zirconium carbide are melt-blended, granulated, and vacuum-dried to obtain polyvinyl acetate / nano-zirconium carbide chips;

[0012] Step 2: Polylactic acid and polyvinyl acetate / zirconium carbide nano chips are melt-blended, granulated, and vacuum dried to obtain polylactic acid-based chips for preparing high-efficiency photothermal responsive chips.

[0013] Furthermore, the viscosity-average molecular weight of polyvinyl acetate in step 1 is 2.5 × 10⁻⁶. 5 ~4.0×10 5 .

[0014] Preferably, the viscosity-average molecular weight of the polyvinyl acetate in step 1 is 3.0 × 10⁻⁶. 5 .

[0015] Furthermore, in step 1, the nano-zirconium carbide particles have a diameter of 10–500 nm.

[0016] Furthermore, in step 1, the mass ratio of polyvinyl acetate to nano-zirconium carbide is 99.99:(0.001-15).

[0017] Preferably, the mass ratio of polyvinyl acetate to nano-zirconium carbide in step 1 is 99.99:(0.01-12).

[0018] Furthermore, in steps 1 and 2, the mixture is premixed for 1 to 15 minutes before granulation.

[0019] Furthermore, in steps 1 and 2, the granulation temperature is 130–250°C and the rotation speed is 50–500 rpm.

[0020] Furthermore, in steps 1 and 2, the vacuum drying temperature is 35–120°C, and the time is 8–48 hours.

[0021] Furthermore, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:(2-4).

[0022] Preferably, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:3.

[0023] This invention provides a method for preparing high-efficiency photothermal responsive polylactic acid fibers, the method comprising the following steps:

[0024] Step 1: Polyvinyl acetate and nano-zirconium carbide are melt-blended, granulated, and vacuum-dried to obtain polyvinyl acetate / nano-zirconium carbide chips;

[0025] Step 2: Polylactic acid and polyvinyl acetate / nano zirconium carbide chips are melt-blended, granulated, and vacuum dried to obtain polylactic acid / polyvinyl acetate / nano zirconium carbide chips.

[0026] Step 3: Polylactic acid / polyvinyl acetate / nano zirconium carbide chips are melt-spun, and after spinning, they are first stretched and then heat-set to obtain high-efficiency photothermal responsive polylactic acid fibers.

[0027] Furthermore, the viscosity-average molecular weight of polyvinyl acetate in step 1 is 2.5 × 10⁻⁶. 5 ~4.0×10 5 .

[0028] Preferably, the viscosity-average molecular weight of the polyvinyl acetate in step 1 is 3.0 × 10⁻⁶. 5 .

[0029] Furthermore, in step 1, the nano-zirconium carbide particles have a diameter of 10–500 nm.

[0030] Furthermore, in step 1, the mass ratio of polyvinyl acetate to nano-zirconium carbide is 99.99:(0.001-15).

[0031] Preferably, the mass ratio of polyvinyl acetate to nano-zirconium carbide in step 1 is 99.99:(0.01-12).

[0032] Furthermore, in steps 1 and 2, the mixture is premixed for 1 to 15 minutes before granulation.

[0033] Furthermore, in steps 1 and 2, the granulation temperature is 130–250°C and the rotation speed is 50–500 rpm.

[0034] Furthermore, in steps 1 and 2, the vacuum drying temperature is 35–120°C, and the time is 8–48 hours.

[0035] Furthermore, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:(2-4).

[0036] Preferably, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:3.

[0037] Furthermore, in step 3, the spinning temperature is 150–250℃ and the spinning speed is 500–5000 m / min.

[0038] Furthermore, the stretching parameters mentioned in step 3 are: stretching temperature of 65–120°C and stretching ratio of 1.5–10.0.

[0039] Furthermore, the heat setting temperature in step 3 is 90–135°C.

[0040] This invention provides a method for preparing a high-efficiency photothermal responsive and shape-memory polylactic acid nonwoven material, the preparation method comprising the following steps:

[0041] Step 1: Polyvinyl acetate and nano-zirconium carbide are melt-blended and granulated, and then vacuum-dried to obtain polyvinyl acetate / nano-zirconium carbide chips;

[0042] Step 2: Melt-blend and polyvinyl acetate / zirconium carbide nano chips to obtain polylactic acid / polyvinyl acetate / zirconium carbide nano chips;

[0043] Step 3: Spunbond polylactic acid / polyvinyl acetate / nanozirconium carbide chips to obtain high-efficiency photothermal response and shape memory polylactic acid nonwoven material.

[0044] Furthermore, the viscosity-average molecular weight of polyvinyl acetate in step 1 is 2.5 × 10⁻⁶. 5 ~4.0×10 5 .

[0045] Preferably, the viscosity-average molecular weight of the polyvinyl acetate in step 1 is 3.0 × 10⁻⁶. 5 .

[0046] Furthermore, in step 1, the nano-zirconium carbide particles have a diameter of 10–500 nm.

[0047] Furthermore, in step 1, the mass ratio of polyvinyl acetate to nano-zirconium carbide is 99.99:(0.001-15).

[0048] Preferably, the mass ratio of polyvinyl acetate to nano-zirconium carbide in step 1 is 99.99:(0.01-12).

[0049] Furthermore, in steps 1 and 2, the mixture is premixed for 1 to 15 minutes before granulation.

[0050] Furthermore, in steps 1 and 2, the granulation temperature is 130–250°C and the rotation speed is 50–500 rpm.

[0051] Furthermore, in steps 1 and 2, the vacuum drying temperature is 35–120°C, and the time is 8–48 hours.

[0052] Furthermore, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:(2-4).

[0053] Preferably, in step 2, the mass ratio of polylactic acid and polyvinyl acetate / zirconium carbide nanoparticles is 7:3.

[0054] Furthermore, in step 3, the spunbond temperatures are: Zone 1 temperature 160~250℃, Zone 2 temperature 160~250℃, Zone 3 temperature 160~250℃, conversion box temperature 160~250℃, spinneret temperature 160~250℃, smooth roller temperature 30~100℃, pattern roller temperature 30~100℃; pump supply is 10~100ml / min, and drafting air velocity is 1~50m / s.

[0055] This invention provides high-efficiency photothermal responsive polylactic acid fibers and high-efficiency photothermal responsive and shape memory polylactic acid nonwoven materials prepared according to the above method.

[0056] The present invention provides the application of high-efficiency photothermal responsive polylactic acid fibers and high-efficiency photothermal responsive and shape memory polylactic acid nonwoven materials in the field of clothing.

[0057] Furthermore, the application of the high-efficiency photothermal responsive polylactic acid fibers and high-efficiency photothermal responsive and shape memory polylactic acid nonwoven materials in the preparation of smart wearable thermal management clothing.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] This invention achieves high-efficiency photothermal response polylactic acid fiber and nonwoven material through process control. Specific advantages are as follows:

[0060] 1) The preparation process of the high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention is simple and low in cost. It adopts the melt spinning method, which has little environmental pollution and falls into the category of clean production.

[0061] 2) The high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention uses polylactic acid, which is renewable and biodegradable, as the base material, which solves the problems of resource shortage and environmental pollution that exist in the use of petroleum-based materials.

[0062] 3) The high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention have excellent photothermal response performance, which can raise the surface temperature by more than 10°C. In particular, the nonwoven material also has the performance of photostimulation shape memory response.

[0063] 4) The high-efficiency photothermal responsive polylactic acid fiber and nonwoven material of the present invention improves the dispersion of nanofunctional materials in the polylactic acid matrix. Detailed Implementation

[0064] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0065] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0066] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0067] Source of raw materials

[0068] Polyvinyl acetate: viscosity-average molecular weight 3.0 × 10⁻⁶ 5 Purchased from Yantai Nuoda Chemical Co., Ltd.

[0069] Polylactic acid: Model 2500HP, D-LA content 0.25%, viscosity-average molecular weight 2.0×10⁻⁶ 5 Purchased from Nature Works, Inc., USA;

[0070] Zirconium carbide: particle size 0.5μm, purity 99.9%, purchased from Shanghai Pantian Powder Materials Co., Ltd.

[0071] Test methods for breaking strength and elongation at break: The tensile mechanical properties of high-efficiency photothermal responsive polylactic acid materials were tested in accordance with the national standard GB / T 14344-2022 Test method for tensile properties of chemical fiber filaments.

[0072] Method for measuring the average diameter of fibers: For samples prepared using the same experimental parameters, five monofilaments were randomly selected and photographed under an optical fiber microscope. For each optical microscope image, the diameter of the monofilament was measured at three randomly selected locations using ImageJ software, and the average value was taken as the average diameter of the monofilament under those parameters.

[0073] Photothermal response performance testing method: Use a solar simulator (simulating solar radiation intensity of 1000 W / m²) 2 Highly efficient photothermal responsive polylactic acid fibers and nonwoven materials were irradiated. When testing the fibers, the fibers were arranged in a 5cm square, and the temperature change of the sample was recorded using an infrared thermal imager. The irradiation time was 5 minutes.

[0074] Photostimulated shape memory performance testing method: First, the shape of the high-efficiency photothermal responsive and shape memory polylactic acid spunbond nonwoven material is pre-programmed. The high-efficiency photothermal responsive and shape memory polylactic acid spunbond nonwoven material is placed in an 80℃ oven and heated for 5 minutes. After removal, its end (approximately 1 cm long) is bent to a 90° angle under continuous external force, while being rapidly cooled. The pre-programmed sample strip is then tested using a solar simulator (simulating sunlight intensity of 1000 W / m²). 2 The sample was irradiated and recorded using a camera. The bending angle change of the sample strip was extracted using ImageJ software, and the shape fixation rate (Rb) was calculated using a formula. f ) and shape recovery rate (R r ).

[0075] Crystallinity test method: Weigh 5 mg of sample and place it in a crucible to prepare the sample to be tested. Test using a DSCQ200 at a nitrogen flow rate of 50 ml / min and a heating rate of 10 °C / min. The crystallinity is determined based on the areas of the cold crystallization peak and the melting peak.

[0076] Example 1

[0077] The preparation method of a high-efficiency photothermal responsive polylactic acid fiber in this embodiment is carried out according to the following steps:

[0078] Step 1:

[0079] First, the viscosity-average molecular weight was 3.0 × 10⁻⁶. 5 Polyvinyl acetate and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to the mass ratio of polyvinyl acetate to ZrC of 99.99:0.01 and premixed in a high-speed mixer for 5 minutes. Then, the mixture was melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum-dried at 105°C for 24 hours to obtain polyvinyl acetate / nano-zirconium carbide chips.

[0080] Step 2:

[0081] With a viscosity-average molecular weight of 2.0 × 10⁻⁶ 5Polylactic acid (PLA) and polyvinyl acetate (PVC) / zirconia nanocarbide chips were dried in a vacuum oven at 75°C for 24 hours for later use. Then, the raw materials were weighed according to a mass ratio of PLA to PVC / zirconia nanocarbide chips of 70:30, premixed in a high-speed mixer for 5 minutes, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the materials were vacuum dried at 75°C for 24 hours to obtain PLA / PVC / zirconia nanocarbide chips.

[0082] Step 3:

[0083] Polylactic acid / polyvinyl acetate / nanozirconium carbide chips were used for melt spinning; then, the high-efficiency photothermal responsive polylactic acid nascent fibers were drawn at a temperature of 80℃ and a draw ratio of 4.0; finally, they were heat-set at a temperature of 120℃ to obtain high-efficiency photothermal responsive polylactic acid fibers.

[0084] Example 2

[0085] This embodiment is prepared according to the process in Example 1, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 99.9:0.1, and the other steps remain unchanged.

[0086] Example 3

[0087] This embodiment is prepared according to the process in Example 1, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 99:1, and the other steps remain unchanged.

[0088] Example 4

[0089] This embodiment is prepared according to the process in Example 1, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 90:10, and the other steps remain unchanged.

[0090] Compare with Example 1

[0091] Step 1:

[0092] First, the viscosity-average molecular weight was 2.0 × 10⁻⁶. 5 The polylactic acid has a viscosity-average molecular weight of 3.0 × 10⁻⁶. 5 Polyvinyl acetate was dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to the mass ratio of polylactic acid to polyvinyl acetate of 70:30, premixed in a high-speed mixer for 5 minutes, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, it was vacuum dried at 105°C for 24 hours to obtain polylactic acid / polyvinyl acetate chips.

[0093] Step 2:

[0094] Polylactic acid / polyvinyl acetate chips were used for melt spinning; then the high-efficiency photothermal responsive polylactic acid nascent fibers were drawn at a temperature of 80°C and a draw ratio of 4.0; finally, they were heat-set at a temperature of 120°C to obtain high-efficiency photothermal responsive polylactic acid fibers.

[0095] Compare with Example 2

[0096] Step 1:

[0097] First, the viscosity-average molecular weight was 2.0 × 10⁻⁶. 5 Polylactic acid and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to the mass ratio of polylactic acid to ZrC of 97:3 and premixed in a high-speed mixer for 5 minutes. Then, they were melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, they were vacuum dried at 105°C for 24 hours to obtain polyvinyl acetate / nano-zirconium carbide chips.

[0098] Step 2:

[0099] Polylactic acid / zirconium carbide nano chips were used for melt spinning; then, the high-efficiency photothermal responsive polylactic acid nascent fibers were drawn at a temperature of 80℃ and a draw ratio of 4.0; finally, they were heat-set at a temperature of 120℃ to obtain high-efficiency photothermal responsive polylactic acid fibers.

[0100] Compare with Example 3

[0101] This control example is a comparison of Example 4, in which the amount of ZrC added is the same, at 3%.

[0102] Step 1:

[0103] First, the viscosity-average molecular weight was 3.0 × 10⁻⁶. 5 Polyvinyl acetate and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to a mass ratio of polyvinyl acetate to ZrC of 90:10 and premixed in a high-speed mixer for 5 minutes. Then, they were melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, they were vacuum dried at 105°C for 24 hours to obtain polyvinyl acetate / nano-zirconium carbide chips.

[0104] Step 2:

[0105] With a viscosity-average molecular weight of 2.0 × 10⁻⁶ 5Polylactic acid (PLA), polyvinyl acetate (PVC) / zirconia nanocarbide (ZN Carbide) chips were dried in a vacuum oven at 75°C for 24 hours for later use. Then, the raw materials were weighed according to a mass ratio of PLA to PVC / ZN Carbide (ZN Carbide) of 70:30 and premixed in a high-speed mixer for 5 minutes. Then, the mixture was melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum-dried at 75°C for 24 hours to obtain PLA / PVC / ZN Carbide (ZN Carbide) chips.

[0106] Step 3:

[0107] Polylactic acid / polyvinyl acetate / nano-zirconium carbide chips were used for melt spinning at a temperature of 195℃ and a spinning speed of 3000m / min to obtain high-efficiency photothermal responsive polylactic acid nascent fibers.

[0108] Example 5

[0109] Step 1:

[0110] First, the viscosity-average molecular weight was 3.0 × 10⁻⁶. 5 Polyvinyl acetate and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to the mass ratio of polyvinyl acetate to ZrC of 99.99:0.01 and premixed in a high-speed mixer for 5 minutes. Then, the mixture was melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum-dried at 105°C for 24 hours to obtain polyvinyl acetate / nano-zirconium carbide chips.

[0111] Step 2:

[0112] With a viscosity-average molecular weight of 2.0 × 10⁻⁶ 5 Polylactic acid (PLA) and polyvinyl acetate (PVC) / zirconia nanocarbide chips were dried in a vacuum oven at 75°C for 24 hours for later use. Then, the raw materials were weighed according to a mass ratio of PLA to PVC / zirconia nanocarbide chips of 70:30, premixed in a high-speed mixer for 5 minutes, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the materials were vacuum dried at 75°C for 24 hours to obtain PLA / PVC / zirconia nanocarbide chips.

[0113] Step 3:

[0114] Polylactic acid / polyvinyl acetate / nano-zirconium carbide chips were used for spunbonding. The spunbonding temperatures were: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, conversion box 190℃, spinneret 190℃, smooth roller 60℃, pattern roller 60℃, pump flow rate 10ml / min, and drafting air velocity 10m / s, resulting in a high-efficiency photothermal response and shape memory polylactic acid spunbond nonwoven material.

[0115] Example 6

[0116] This embodiment is prepared according to the process in Example 5, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 99.9:0.1, and the other steps remain unchanged.

[0117] Example 7

[0118] This embodiment is prepared according to the process in Example 5, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 99:1, and the other steps remain unchanged.

[0119] Example 8

[0120] This embodiment is prepared according to the process in Example 5, except that the mass ratio of polyvinyl acetate to ZrC in step 1 is changed to 90:10, and the other steps remain unchanged.

[0121] Compare with Example 4

[0122] Step 1:

[0123] First, the viscosity-average molecular weight was 2.0 × 10⁻⁶. 5 The polylactic acid has a viscosity-average molecular weight of 3.0 × 10⁻⁶. 5 Polyvinyl acetate was dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to the mass ratio of polylactic acid to polyvinyl acetate of 70:30, premixed in a high-speed mixer for 5 minutes, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, it was vacuum dried at 105°C for 24 hours to obtain polylactic acid / polyvinyl acetate chips.

[0124] Step 2:

[0125] Polylactic acid / polyvinyl acetate chips were used for spunbonding. The spunbonding temperatures were: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, transfer box 190℃, spinneret 190℃, smooth roller 60℃, and pattern roller 60℃. The pump flow rate was 10 ml / min, and the drafting air velocity was 10 m / s.

[0126] Compare with Example 5

[0127] This control example is a comparison of Example 8, in which the amount of ZrC added is the same, at 3%.

[0128] Step 1:

[0129] First, the viscosity-average molecular weight was 2.0 × 10⁻⁶. 5 Polylactic acid (PLA) and nano-zirconia (ZrC) were dried in a vacuum oven at 45°C for 24 hours and set aside. Then, the raw materials were weighed according to a mass ratio of PLA to ZrC of 97:3 and premixed in a high-speed mixer for 5 minutes. The mixture was then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum-dried at 105°C for 24 hours to obtain PLA / nano-zirconia chips.

[0130] Step 2:

[0131] Polylactic acid / nano-zirconium carbide chips were used for spunbonding at the following temperatures: Zone 1: 190℃, Zone 2: 195℃, Zone 3: 200℃, Conversion box: 190℃, Spinneret: 190℃, Smoothing roller: 60℃, Pattern roller: 60℃, Pump feed rate: 10ml / min, Drafting air velocity: 10m / s. This resulted in a high-efficiency photothermal responsive and shape-memory polylactic acid spunbond nonwoven material.

[0132] Test Results

[0133] (I) The high-efficiency photothermal responsive polylactic acid fibers of Examples 1-4 and Control Examples 1-3 were characterized and tested for mechanical properties, photothermal response properties, photostimulated shape memory properties, and crystallinity properties. The specific test results are shown in Table 1.

[0134] As shown in Table 1:

[0135] (1) Compared with Control Example 1, pure polylactic acid / polyvinyl acetate fibers have no photothermal response properties, while high-efficiency photothermal response polylactic acid fibers with added ZrC have significant photothermal effects.

[0136] (2) Compared with Comparative Example 2, the increase in polyvinyl acetate content in Example 4 is beneficial to the improvement of photothermal performance. This is because the addition of polyvinyl acetate improves the dispersion of nano-zirconium carbide in the matrix, enabling zirconium carbide to fully absorb light.

[0137] (3) Compared with the control example 3, the breaking strength of the high-efficiency photothermal responsive polylactic acid fiber after thermal stretching is 1.9 times that of the nascent fiber, and it has increased from 1.22 cN / dtex to 2.33 cN / dtex.

[0138] Table 1 Comparison of Performance Test Results of High-Efficiency Photothermal Response Polylactic Acid Fiber

[0139]

[0140] (II) The high-efficiency photothermal response and shape memory polylactic acid nonwoven materials of Examples 5-8 and Control Examples 4-5 were characterized and tested for diameter, mechanical properties, photothermal response properties, and shape memory properties. The specific test results are shown in Table 2 below:

[0141] Table 2 Comparison of Performance Test Results of High-Efficiency Photothermal Response and Shape Memory Polylactic Acid Spunbond Nonwoven Materials

[0142]

[0143] It can be seen from Table 2 above:

[0144] (1) Compared with Control Example 4, pure polylactic acid / polyvinyl acetate nonwoven materials in Examples 5-8 have no photothermal response and shape memory properties, while the high-efficiency photothermal response and shape memory polylactic acid spunbond nonwoven materials with added ZrC have significant photothermal effects and shape memory properties.

[0145] (2) Compared with Comparative Example 5, the addition of polyvinyl acetate in Example 8 is beneficial to improving the photothermal response and shape memory properties of polylactic acid nonwoven materials with high efficiency photothermal response and shape memory.

[0146] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing high-efficiency photothermal responsive polylactic acid fibers, characterized in that, Includes the following steps: Step 1: First, the viscosity-average molecular weight is Polyvinyl acetate and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 h for later use. Then, the raw materials were weighed according to the mass ratio of polyvinyl acetate to ZrC of 99.99:0.01, premixed in a high-speed mixer for 5 min, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum dried at 105°C for 24 h to obtain polyvinyl acetate / nano-zirconium carbide chips. Step 2: With viscosity-average molecular weight Polylactic acid (PLA) and polyvinyl acetate / zirconia nanoparticle chips were dried in a vacuum oven at 75°C for 24 h for later use. Then, the raw materials were weighed according to a mass ratio of PLA to polyvinyl acetate / zirconia nanoparticle chips of 90:10, premixed in a high-speed mixer for 5 min, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the materials were vacuum dried at 75°C for 24 h to obtain PLA / polyvinyl acetate / zirconia nanoparticle chips. Step 3: Polylactic acid / polyvinyl acetate / nanozirconium carbide chips were used for melt spinning; then, the high-efficiency photothermal responsive polylactic acid nascent fibers were drawn at a temperature of 80℃ and a draw ratio of 4.0; finally, they were heat-set at a temperature of 120℃ to obtain high-efficiency photothermal responsive polylactic acid fibers.

2. A high-efficiency photothermal responsive polylactic acid fiber prepared according to the method of claim 1.

3. A method for preparing a high-efficiency photothermal responsive and shape-memory polylactic acid nonwoven material, characterized in that, The preparation method includes the following steps: Step 1: First, the viscosity-average molecular weight is Polyvinyl acetate and nano-zirconium carbide (ZrC) were dried in a vacuum oven at 45°C for 24 h for later use. Then, the raw materials were weighed according to the mass ratio of polyvinyl acetate to ZrC of 99.99:0.01, premixed in a high-speed mixer for 5 min, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the mixture was vacuum dried at 105°C for 24 h to obtain polyvinyl acetate / nano-zirconium carbide chips. Step 2: With viscosity-average molecular weight Polylactic acid (PLA) and polyvinyl acetate / zirconia nanoparticle chips were dried in a vacuum oven at 75°C for 24 h for later use. Then, the raw materials were weighed according to a mass ratio of PLA to polyvinyl acetate / zirconia nanoparticle chips of 90:10, premixed in a high-speed mixer for 5 min, and then melt-blended and granulated in a twin-screw mixer at a granulation temperature of 185°C and a screw speed of 400 rpm. Finally, the materials were vacuum dried at 75°C for 24 h to obtain PLA / polyvinyl acetate / zirconia nanoparticle chips. Step 3: Polylactic acid / polyvinyl acetate / nano-zirconium carbide chips were used for spunbonding. The spunbonding temperatures were: Zone 1 190℃, Zone 2 195℃, Zone 3 200℃, conversion box 190℃, spinneret 190℃, smooth roller 60℃, pattern roller 60℃, pump flow rate 10ml / min, and drafting air velocity 10m / s, resulting in a high-efficiency photothermal response and shape memory polylactic acid spunbond nonwoven material.

4. A high-efficiency photothermal responsive and shape memory polylactic acid nonwoven material prepared by the method according to claim 3.

5. The application of the high-efficiency photothermal responsive polylactic acid fiber as described in claim 2 and the high-efficiency photothermal responsive and shape memory polylactic acid nonwoven material as described in claim 4 in the field of clothing.

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