Electro-rotatory composite yarn based on liquid crystal elastomer fibers and method for manufacturing the same

Abstract

The present application relates to a kind of electro-rotatory composite yarn based on liquid crystal elastomer fiber and its preparation method, first using the method of improved wet spinning to prepare liquid crystal elastomer fiber, then through the method of improved ring spinning to make liquid crystal elastomer fiber and flexible conductive yarn twist, prepare electro-rotatory composite yarn based on liquid crystal elastomer fiber;Electro-rotatory composite yarn based on liquid crystal elastomer fiber prepared is by liquid crystal elastomer fiber and flexible conductive yarn one end hold, the other end turns and is twisted and is made plying yarn;Electro-rotatory composite yarn based on liquid crystal elastomer fiber, untwist occurs positive rotation movement under voltage stimulation, and reverse rotation movement occurs after voltage stimulation is removed, gradually restore twist degree.The preparation method of the present application is simple and convenient;Electro-rotatory composite yarn based on liquid crystal elastomer fiber prepared can realize the accurate control of rotation movement under voltage stimulation, with the advantages of small energy consumption, high driving efficiency, control system is simple and so on.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent driving yarns, and relates to an electro-rotating composite yarn based on a liquid crystal elastomer fiber and a preparation method thereof. BACKGROUND

[0002] An intelligent driving yarn is a soft and slender fiber assembly that converts external energy input into movement. According to the functions and properties of the fiber material, the intelligent driving yarn prepared through structural design has the advantages of flexibility, softness and strain controllability and gradually becomes a hot research content in the fields of scientific exploration, medical care, military reconnaissance, industrial rescue and the like.

[0003] A liquid crystal elastomer (LCE) fiber is a fibrous soft active material. Liquid crystal groups in a low cross-linking density liquid crystal network can be oriented and fixed along the fiber stretching direction (director) under external mechanical action, and can undergo a transition from a nematic phase to an isotropic phase when the temperature reaches the phase transition temperature, which macroscopically exhibits radial shrinkage of the fiber material. The reversible shrinkage process and large shrinkage strain make the LCE driving fiber widely concerned.

[0004] At present, the LCE fiber is mainly prepared by a melt extrusion method. The molten mixture is stretched to form a fibrous LCE under the self-weight in the extrusion process. This fiber preparation method is affected by many factors, such as uneven stretching caused by air flow in the air and fiber forming affected by changes in the ambient temperature. Stable and continuous preparation of uniform LCE fibers is an important problem to be solved in the current process.

[0005] In addition, the driving mode of the LCE fiber is also a hot content in the current research. The LCE driving fiber can be divided into thermal driving (direct heating and photo-thermal) and photo-chemical driving according to the driving mode. The photo-chemical driving needs different wavelengths of light to trigger the forward and reverse response, and the driving mode is complex. Therefore, the photo-thermal driving is the most studied driving mode at present. The driving modes involved in patents CN113800464A and CN107365401A are both near-infrared photo-thermal driving. However, the photo-thermal driving needs to collect light energy before the temperature reaches the phase transition temperature, and the driving efficiency is low. Electric heating is a new driving mode. The electronic element is integrated with the LCE fiber, and the Joule heat generated by the electronic element is controlled by input power to realize accurate control of the shrinkage amount of the liquid crystal elastomer fiber. However, the integration of the LCE fiber and the electronic element is challenging. The rigid electronic element will limit the shrinkage movement of the LCE fiber, which does not meet the flexible and soft characteristics of the flexible driving yarn. The flexible electronic element such as liquid metal (LM) needs to design a skin-core structure for the LCE fiber, and the process is complex.

[0006] It is of great significance to integrate flexible electronic components with LCE fibers simply and efficiently for the industrialized production of subsequent driving yarns.

[0007] Finally, the driving mode of LCE fibers is single, only contraction and elongation along the fiber axis, which greatly reduces the application scenarios of LCE driving yarns.

[0008] To solve the above problems, it is of great significance to study an electro-rotating composite yarn based on liquid crystal elastomer fibers and a preparation method thereof. SUMMARY

[0009] To solve the problems in the prior art, the application provides an electro-rotating composite yarn based on liquid crystal elastomer fibers and a preparation method thereof.

[0010] To achieve the above-mentioned purpose, the application adopts the following scheme:

[0011] An electro-rotating composite yarn based on liquid crystal elastomer fibers is a ply yarn formed by holding one end of a liquid crystal elastomer (LCE) fiber and a flexible conductive yarn and rotating the other end, in one twist return, the liquid crystal elastomer fiber and the flexible conductive yarn rotate one circle in the same direction around the fiber axis, and the relative positions are exchanged twice (after one twist return, the relative positions of the two yarns at the twist return are consistent with the initial positions); the liquid crystal elastomer fiber and the flexible conductive yarn in the ply yarn are extruded at the twist return, Along the fiber obtain friction in the length direction and interlock to form a stable structure under the condition of ultraviolet curing; ultraviolet curing fixes the twist of the liquid crystal elastomer fiber, and the liquid crystal elastomer fiber and the flexible conductive yarn are interlocked by obtaining friction in the length direction to further fix the twist of the ply yarn and form a stable structure;

[0012] The electro-rotating composite yarn based on liquid crystal elastomer fibers is positively rotated under voltage stimulation and reversely rotated after the voltage stimulation is removed, and gradually recovers the twist.

[0013] After the voltage stimulation is applied, the rotating composite yarn is actuated under the voltage stimulation, and the following relationship is satisfied:

[0014]

[0015] wherein Q is the heat generated by the ply yarn, U is the input voltage, R is the resistance of the ply yarn, t is the time of voltage input, m is the mass of the ply yarn, c is the heat capacity value of the unit mass of the ply yarn, and ΔT is the temperature change of the ply yarn; when the temperature change of the ply yarn reaches the phase transition temperature of the liquid crystal elastomer, the rotating composite yarn reaches the maximum rotation speed and the number of turns.

[0016] The relationship between the rotation speed, torque and input voltage can be obtained from the data graph, and the 10cm long rotating composite yarn can output a rotation speed of up to 480rpm under the stimulation of 6V voltage, and can further generate a torque of 160uN*m. The number of rotations depends on the twist of the introduced ply yarn, and when the temperature of the system reaches the phase transition temperature, the ply yarn is completely untwisted, and the number of rotations n can be expressed by the following formula:

[0017] n = T m L;

[0018] T m is the twist of the introduced yarn, and L is the length of the ply yarn.

[0019] As a preferred technical solution:

[0020] The flexible conductive yarn is a gold-plated molybdenum wire, a nickel-titanium alloy wire, a stainless steel wire, a carbon nanotube yarn, a carbon fiber yarn or a silver-plated nylon yarn.

[0021] The liquid crystal elastomer fiber and the flexible conductive yarn are twisted at a ratio of 1:1, so that the obtained yarn is uniformly stressed and has a stable structure.

[0022] The twist of the liquid crystal elastomer fiber-based electro-rotating composite yarn is 300-1200 twists / m.

[0023] The application also provides a preparation method of the liquid crystal elastomer fiber-based electro-rotating composite yarn.

[0024] Unlike the traditional wet spinning coagulation bath forming, the improvement of the improved wet spinning is that the spinning solution is cured and formed by a UV point light source after extrusion; in the first step of the improved wet spinning process, the UV point light source is irradiated, the diameter of the UV point light source is 0.8cm, the wavelength is 365nm, the power density is 2-5mW / cm 2 , and the UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed (the actual time is very short, and the curing can be completed within 1-2min), the low power density of the UV light and the short irradiation time make the fiber preliminary polymerize and maintain the basic fiber form;

[0025] The improved ring spinning is to place the bobbin of the ring device in a topless ultraviolet box, and the bobbin performs photopolymerization reaction in the process of rotary twisting; in the second step of the improved ring spinning, a surface light source ultraviolet lamp is used for irradiation to cause photopolymerization reaction, the ultraviolet light in the ultraviolet box has a wavelength of 365 nm and a power density of 15-30 mW / cm 2 , and the yarn twist is fixed.

[0026] The preparation method of the electro-rotatory composite yarn based on the liquid crystal elastomer fiber as described above, the spinning solution is a mixture of liquid crystal monomers, spacers, cross-linking agents, photoinitiators, catalysts and organic solvents, the molar ratio (mass ratio) of the liquid crystal monomers to the spacers is 1-2:1, the molar ratio of the liquid crystal monomers to the cross-linking agents is 6-12:1, the molar ratio of the liquid crystal monomers to the organic solvents is 34:1, and the photoinitiator and the catalyst each account for 2% of the total molar amount of the mixture.

[0027] The preparation method of the electro-rotatory composite yarn based on the liquid crystal elastomer fiber as described above, the liquid crystal monomers are acrylate, including RM257 (4-(3-acryloyloxypropoxy) benzoic acid 2-methyl-1, 4-phenyl ester), RM82 (1, 4-diphenol bis (4-(6-acryloyloxy) hexyloxy) benzoic acid)-2-methyl ester), the organic solvent is acetone, toluene or dichloromethane, the photoinitiator is HHMP (2-hydroxy-4'-(2-hydroxyethoxy)-2-methyl benzophenone) or IG651 (benzoin dimethyl ether), the spacer is EDDET (2, 2'-(1, 2-ethylenedioxy) bisethanethiol), the cross-linking agent is PETMP (pentaerythritol tetra-3-mercapto propionic acid ester), and the catalyst is di-n-propylamine.

[0028] The preparation method of the electro-rotatory composite yarn based on the liquid crystal elastomer fiber as described above, the spinning solution is pre-crosslinked at room temperature (25°C) for 15-30 min before being extruded, and the extrusion speed is 3-5 mm / min; the pre-crosslinking function is to make the monomers form oligomers in advance, so that the spinning solution can be formed into strands without flow interruption during extrusion, and the state of the spinning solution at this time is a liquid with certain viscosity.

[0029] The preparation method of the electro-rotatory composite yarn based on the liquid crystal elastomer fiber as described above, the specific process of twisting the liquid crystal elastomer fiber and the flexible conductive yarn by the improved ring spinning method is as follows: the collected liquid crystal elastomer fiber and the flexible conductive yarn are fed into the twisting device through the roller, the rotation of the spindle makes the ring rotate along the ring rail and drives the sliver to rotate to complete the twisting, the speed difference between the ring and the bobbin makes the sliver wind onto the bobbin, and the bobbin is placed in the ultraviolet box during the rotation process to make the yarn perform the second step of photopolymerization reaction.

[0030] A preparation method of the electro-rotating composite yarn based on the liquid crystal elastomer fiber as described above, the rotating speed of the bobbin is 72-90 rpm, and the rotating speed (linear speed) of the ring is 9.7-12.1 m / min.

[0031] The principle of the present application is:

[0032] The oriented fixed LCE fiber (i.e. liquid crystal elastomer fiber) is affected by temperature and can produce corresponding phase change shrinkage. By using this mechanism, the present application prepares uniform LCE fibers by improving the wet spinning method, and integrates the LCE fibers with flexible resistance elements by improving the ring spinning method, and continuously produces intelligent driving cheese. The preparation of LCE fibers is based on a two-step reaction method of Michael addition and photopolymerization. In the second step of the photopolymerization reaction, the orientation of the LCE fiber is fixed, and the natural elongation of the fiber during the twisting process is used to replace the artificial mechanical stretching (the conventional pre-orientation method of LCE fibers at present is stretching along the fiber axis, and such fibers can shrink and elongate in the fiber length after photopolymerization. In the present application, the pre-orientation method of LCE fibers is twisting, and the LCE fibers at the twist return position are elongated under the action of twisting to produce a spiral structure, and the parts outside the twist return position remain in the original fiber form. Such fibers can produce rotation along the fiber axis after photopolymerization), and the UV photopolymerization reaction fixes the twist return of the LCE fiber. The finally prepared electro-rotating composite yarn can realize reversible rotation under the periodic stimulation of voltage, the maximum rotating speed can be controlled by voltage, and the number of rotation can be controlled by the introduced twist.

[0033] Advantages

[0034] (1) The preparation method of the electro-rotating composite yarn based on the liquid crystal elastomer fiber of the present application is simple and convenient, and can continuously produce intelligent rotating composite yarns after design;

[0035] (2) The electro-rotating composite yarn based on the liquid crystal elastomer fiber of the present application can realize precise control of rotating motion under voltage stimulation, has the advantages of small energy consumption, high driving efficiency, simple control system, etc.;

[0036] (3) The electro-rotating composite yarn based on the liquid crystal elastomer fiber of the present application improves the single strain mode of traditional LCE fibers, and changes the contraction and relaxation of the fiber axis into rotating motion through structural design, widens the application scenarios of LCE fibers, and can be applied to complex movements of artificial muscles and soft robots. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 It is a process flow chart of the electro-rotating composite yarn based on the liquid crystal elastomer fiber;

[0038] Figure 2A schematic diagram of the structure of the electro-rotatory composite yarn based on liquid crystal elastomer fiber;

[0039] Figure 3 A schematic diagram of the electro-rotatory principle of the electro-rotatory composite yarn based on liquid crystal elastomer fiber;

[0040] Figure 4 The maximum rotation speed and torque output of the electro-rotatory composite yarn based on liquid crystal elastomer fiber under different voltage stimuli. DETAILED DESCRIPTION

[0041] The application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content taught by the application, and these equivalent forms also fall within the scope of the appended claims.

[0042] In the application, the twist of the yarn is fixed by photopolymerization, and the introduced twist calculation formula is: In the formula, v is the rotation speed of the steel ring, t is the time, r is the radius of the ring, and L0 is the winding length of the cheese.

[0043] Example 1

[0044] A preparation method of an electro-rotatory composite yarn based on liquid crystal elastomer fiber, as shown in Figure 1 The specific steps are as follows:

[0045] (1) Preparation of the spinning solution: the spinning solution is a mixture of RM257, EDDET, PETMP, HHMP, di-n-propylamine and acetone;

[0046] Among them, the molar ratio of RM257 to EDDET is 2:1, the molar ratio of RM257 to PETMP is 6:1, and the molar ratio of RM257 to acetone is 34:1, and HHMP and di-n-propylamine each account for 2% of the total molar amount of the mixture;

[0047] (2) The improved wet spinning method is used, that is, the spinning solution is pre-crosslinked at room temperature for 15 min and then extruded at a speed of 3 mm / min, and cured and formed by a UV point light source to prepare a liquid crystal elastomer (LCE) fiber;

[0048] Among them, the diameter of the UV point light source is 0.8 cm, the power density is 5 mW / cm 2 , and the UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed;

[0049] (3) as Figure 2As shown, the liquid crystal elastomer fiber collected is fed into the twisting device with silver-plated nylon yarn in a 1:1 ratio by roller feeding, and the twist is completed by the rotation of the spindle, which rotates the ring along the ring rail and drives the sliver to rotate. The difference in speed between the ring and the bobbin placed in the open-top ultraviolet box causes the sliver to be wound onto the bobbin. The bobbin undergoes a photopolymerization reaction during the rotation and twisting process to produce liquid crystal elastomer fiber-based electro-rotating composite yarn.

[0050] The ultraviolet light power density in the improved ring spinning ultraviolet box is 15 mW / cm 2 , and the ultraviolet light irradiation time is 50 min; the speed of the bobbin is 72 rpm, and the speed of the ring is 9.7 m / min.

[0051] The liquid crystal elastomer fiber-based electro-rotating composite yarn produced is a plying yarn formed by holding one end of the liquid crystal elastomer fiber and the silver-plated nylon yarn and rotating and twisting the other end. In one twist, the liquid crystal elastomer fiber and the silver-plated nylon yarn rotate one circle around the fiber axis in the same direction at the rotating end, and the relative positions are exchanged twice. The liquid crystal elastomer fiber and the silver-plated nylon yarn in the plying yarn are pressed against each other at the twist, generating friction along the length of the fiber and interlocking under the condition of ultraviolet curing to form a stable structure. Figure 3 As shown, the liquid crystal elastomer fiber-based electro-rotating composite yarn undergoes positive rotation under voltage stimulation and reverse rotation after the voltage stimulation is removed, gradually recovering the twist. The twist of the liquid crystal elastomer fiber-based electro-rotating composite yarn is 1200 twists / m. Figure 4 As shown, a 10 cm long liquid crystal elastomer fiber-based electro-rotating composite yarn can output a speed of up to 480 rpm under a 6V voltage stimulus, and can generate a torque of 160 μN·m. The maximum speed and torque output decrease accordingly as the input voltage decreases, which means that the precise control of the intelligent driving of the yarn rotation can be achieved by different input voltages.

[0052] Example 2

[0053] A method for preparing a liquid crystal elastomer fiber-based electro-rotating composite yarn, the specific steps being as follows:

[0054] (1) Preparation of the spinning solution: the spinning solution is a mixture of RM82, EDDET, PETMP, IG651, di-n-propylamine, and toluene;

[0055] The molar ratio of RM82 to EDDET is 1.8:1, the molar ratio of RM82 to PETMP is 7:1, the molar ratio of RM82 to toluene is 34:1, and IG651 and di-n-propylamine each account for 2% of the total molar amount of the mixture.

[0056] (2) using the improved wet spinning method, i.e. the spinning solution is pre-crosslinked at room temperature for 18 min and then extruded at a speed of 3 mm / min, and cured into shape by a UV point light source to prepare a liquid crystal elastomer (LCE) fiber;

[0057] wherein the diameter of the UV point light source is 0.8 cm, and the power density is 2.5 mW / cm 2 , and the UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed;

[0058] (3) using the improved ring spinning method, i.e. the collected liquid crystal elastomer fiber and the nickel-titanium alloy wire are fed into the twisting device by a roller at a quantity ratio of 1:1, the rotation of the spindle makes the traveler rotate along the ring and drives the sliver to rotate to complete the twisting, the difference in rotation speed between the traveler and the bobbin placed in the UV box without a top makes the sliver wind onto the bobbin, and the bobbin performs photopolymerization reaction during the process of rotation and twisting to prepare an electro-rotating composite yarn based on the liquid crystal elastomer fiber;

[0059] wherein the UV light power density in the improved ring spinning UV box is 18 mW / cm 2 , and the UV light irradiation time is 45 min; the rotation speed of the bobbin is 75 rpm, and the rotation speed of the traveler is 10 m / min.

[0060] The prepared electro-rotating composite yarn based on the liquid crystal elastomer fiber is a plying yarn formed by holding one end of the liquid crystal elastomer fiber and the nickel-titanium alloy wire and rotating and twisting the other end, in one twist, the liquid crystal elastomer fiber and the nickel-titanium alloy wire rotate one circle in the same direction around the fiber axis at the rotating end, and the relative positions are exchanged twice; the liquid crystal elastomer fiber and the nickel-titanium alloy wire in the plying yarn are extruded at the twist, obtain friction force along the length direction of the fiber, and are positionally interlocked to form a stable structure under the condition of UV curing; the electro-rotating composite yarn based on the liquid crystal elastomer fiber rotates in the positive direction under the voltage stimulation, rotates in the reverse direction after the voltage stimulation is removed, and gradually recovers the twist; the twist of the electro-rotating composite yarn based on the liquid crystal elastomer fiber is 1100 twists / m.

[0061] Example 3

[0062] A preparation method of an electro-rotating composite yarn based on a liquid crystal elastomer fiber, the specific steps are as follows:

[0063] (1) preparation of the spinning solution: the spinning solution is a mixture of RM257, EDDET, PETMP, HHMP, di-n-propylamine and dichloromethane;

[0064] The molar ratio of RM257 to EDDET is 1.6:1, the molar ratio of RM257 to PETMP is 8:1, the molar ratio of RM257 to dichloromethane is 34:1, and the content of HHMP and di-n-propylamine in the total moles of the mixture is 2% respectively;

[0065] (2) The liquid crystal elastomer (LCE) fiber is prepared by using the improved wet spinning method, that is, the spinning solution is pre-crosslinked at room temperature for 20 minutes, then extruded at a speed of 4 mm / min, and cured and shaped by a UV point light source.

[0066] The diameter of the UV point light source is 0.8 cm, and the power density is 3 mW / cm 2 The UV irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed.

[0067] (3) The liquid crystal elastomer fiber collected is fed into the twisting device with a stainless steel wire at a quantity ratio of 1:1 by a roller, the twisting is completed by the rotation of the ring along the ring rail and the rotation of the yarn, and the yarn is wound on the bobbin by the speed difference between the ring and the bobbin in the UV tank, and the bobbin is simultaneously subjected to photopolymerization during the rotation and twisting, to obtain the electro-rotating composite yarn based on the liquid crystal elastomer fiber.

[0068] The UV power density in the improved ring spinning UV tank is 20 mW / cm 2 , and the UV irradiation time is 40 minutes; the rotation speed of the bobbin is 78 rpm, and the rotation speed of the ring is 10.3 m / min.

[0069] The electro-rotating composite yarn based on the liquid crystal elastomer fiber is a plying yarn held at one end by the liquid crystal elastomer fiber and the stainless steel wire and twisted at the other end, in one twist, the liquid crystal elastomer fiber and the stainless steel wire rotate in the same direction around the fiber axis one circle, and the relative position is exchanged twice; the liquid crystal elastomer fiber and the stainless steel wire in the plying yarn are extruded at the twist, obtain friction along the length of the fiber, and are positionally interlocked to form a stable structure under the condition of UV curing; the electro-rotating composite yarn based on the liquid crystal elastomer fiber rotates in the positive direction under the voltage stimulation, and rotates in the reverse direction after the voltage stimulation is removed, and gradually restores the twist; the twist of the electro-rotating composite yarn based on the liquid crystal elastomer fiber is 1000 twists / m.

[0070] Example 4

[0071] A method for preparing an electro-rotating composite yarn based on a liquid crystal elastomer fiber, the specific steps are as follows:

[0072] (1) Preparation of the spinning solution: the spinning solution is a mixture of RM82, EDDET, PETMP, IG651, di-n-propylamine and acetone;

[0073] wherein the molar ratio of RM82 to EDDET is 1.5:1, the molar ratio of RM82 to PETMP is 9:1, the molar ratio of RM82 to acetone is 34:1, and IG651 and di-n-propylamine each account for 2% of the total molar amount of the mixture;

[0074] (2) The liquid crystal elastomer (LCE) fiber is prepared by using the improved wet spinning method, i.e. the spinning solution is pre-crosslinked at room temperature for 23 min and then extruded at a speed of 4 mm / min, and cured into shape by a UV point light source.

[0075] wherein the diameter of the UV point light source is 0.8 cm, the power density is 3.5 mW / cm 2 , and the UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed;

[0076] (3) The liquid crystal elastomer fiber collected is fed into the twisting device with the carbon nanotube yarn at a quantity ratio of 1:1 by roller feeding, and the twisting is completed by the rotation of the spindle to make the traveler rotate along the ring and drive the yarn to rotate. The difference in speed between the traveler and the bobbin placed in the UV box without top makes the yarn wind onto the bobbin, and the bobbin performs the photopolymerization reaction in the process of rotation and twisting, to obtain the electro-rotating composite yarn based on the liquid crystal elastomer fiber.

[0077] wherein the UV light power density in the improved ring spinning UV box is 23 mW / cm 2 , the UV light irradiation time is 40 min, the speed of the bobbin is 80 rpm, and the speed of the traveler is 10.5 m / min.

[0078] The electro-rotating composite yarn based on the liquid crystal elastomer fiber is a plying yarn formed by holding one end of the liquid crystal elastomer fiber and the carbon nanotube yarn and rotating and twisting the other end. In one twist, the liquid crystal elastomer fiber and the carbon nanotube yarn rotate one circle in the same direction around the fiber axis, and the relative positions are exchanged twice. The liquid crystal elastomer fiber and the carbon nanotube yarn in the plying yarn are extruded at the twist place, obtain friction force along the length direction of the fiber, and are positionally interlocked to form a stable structure under the condition of UV curing. The electro-rotating composite yarn based on the liquid crystal elastomer fiber rotates forward under the voltage stimulation, and rotates reversely after the voltage stimulation is removed, and gradually restores the twist. The twist of the electro-rotating composite yarn based on the liquid crystal elastomer fiber is 900 twists / m.

[0079] Example 5

[0080] A preparation method of an electro-rotating composite yarn based on liquid crystal elastomer fiber, the specific steps are as follows:

[0081] (1) Preparation of spinning solution: the spinning solution is a mixture of RM257, EDDET, PETMP, HHMP, di-n-propylamine and toluene;

[0082] Among them, the molar ratio of RM257 to EDDET is 1.4:1, the molar ratio of RM257 to PETMP is 10:1, and the molar ratio of RM257 to toluene is 34:1; HHMP and di-n-propylamine each account for 2% of the total molar amount of the mixture;

[0083] (2) The method of improved wet spinning is used, that is, the spinning solution is pre-crosslinked at room temperature for 25 min, then extruded at a speed of 5 mm / min, and cured by a UV point light source to prepare a liquid crystal elastomer (LCE) fiber;

[0084] Among them, the diameter of the UV point light source is 0.8 cm, and the power density is 4 mW / cm 2 The UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed;

[0085] (3) The method of improved ring spinning is used, that is, the collected liquid crystal elastomer fiber and carbon fiber yarn are fed into the twisting device through the roller at a quantity ratio of 1:1, the rotation of the spindle makes the traveler rotate along the ring and drives the sliver to rotate to complete the twisting, and the difference between the rotation speed of the traveler and the rotation speed of the bobbin placed in the UV box without top makes the sliver wind onto the bobbin, and the bobbin performs photopolymerization reaction during the rotation and twisting process, to obtain an electro-rotating composite yarn based on liquid crystal elastomer fiber;

[0086] Among them, the UV light power density in the improved ring spinning UV box is 25 mW / cm 2 , and the UV light irradiation time is 35 min; the rotation speed of the bobbin is 85 rpm, and the rotation speed of the traveler is 11 m / min.

[0087] The prepared electro-rotating composite yarn based on liquid crystal elastomer fiber is a plying yarn held by the liquid crystal elastomer fiber and the carbon fiber yarn at one end and twisted at the other end, in one twist, the liquid crystal elastomer fiber and the carbon fiber yarn rotate one circle in the same direction around the fiber axis at the twisted end, and the relative position is exchanged twice; the liquid crystal elastomer fiber and the carbon fiber yarn in the plying yarn are extruded at the twist, obtain friction force along the length direction of the fiber, and are positionally interlocked to form a stable structure under the condition of UV curing; the electro-rotating composite yarn based on liquid crystal elastomer fiber rotates forward under the voltage stimulation, and rotates reversely after the voltage stimulation is removed, and gradually restores the twist; the twist of the electro-rotating composite yarn based on liquid crystal elastomer fiber is 800 twists / m.

[0088] Example 6

[0089] A preparation method of a liquid crystal elastomer fiber-based electro-rotatory composite yarn, the specific steps are as follows:

[0090] (1) Preparation of spinning solution: the spinning solution is a mixture of RM82, EDDET, PETMP, IG651, di-n-propylamine and dichloromethane;

[0091] Among them, the molar ratio of RM82 to EDDET is 1.2:1, the molar ratio of RM82 to PETMP is 11:1, and the molar ratio of RM82 to dichloromethane is 34:1, IG651 and di-n-propylamine each account for 2% of the total molar amount of the mixture;

[0092] (2) The improved wet spinning method is used, that is, the spinning solution is pre-crosslinked at room temperature for 28 min, and then extruded at a speed of 5 mm / min, and cured and shaped by a UV point light source to prepare a liquid crystal elastomer (LCE) fiber;

[0093] Among them, the diameter of the UV point light source is 0.8 cm, and the power density is 4.5 mW / cm 2 The UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed;

[0094] (3) The improved ring spinning method is used, that is, the collected liquid crystal elastomer fiber and silver-plated nylon yarn are fed into the twisting device by roller at a quantity ratio of 1:1, the rotation of the spindle makes the traveler rotate along the ring and drives the sliver to rotate to complete the twisting, and the difference between the rotation speed of the traveler and the bobbin placed in the UV box without top makes the sliver wind onto the bobbin. During the process of rotation and twisting, the bobbin simultaneously performs photopolymerization reaction to obtain a liquid crystal elastomer fiber-based electro-rotatory composite yarn;

[0095] Among them, the UV light power density in the improved ring spinning UV box is 28 mW / cm 2 , the UV light irradiation time is 35 min; the rotation speed of the bobbin is 88 rpm, and the rotation speed of the traveler is 11.5 m / min.

[0096] The prepared liquid crystal elastomer fiber-based electro-rotating composite yarn is a plying yarn held by the liquid crystal elastomer fiber and the silver-plated nylon yarn at one end and twisted at the other end. In one twist, the liquid crystal elastomer fiber and the silver-plated nylon yarn at the twisted end rotate one circle in the same direction around the fiber axis, and the relative positions are exchanged twice. The liquid crystal elastomer fiber and the silver-plated nylon yarn in the plying yarn are extruded at the twist, obtain friction force along the length direction of the fiber, and are positionally interlocked to form a stable structure under the condition of ultraviolet curing. The liquid crystal elastomer fiber-based electro-rotating composite yarn is positively rotated under the voltage stimulation, and is reversely rotated after the voltage stimulation is removed, and gradually restores the twist. The twist of the liquid crystal elastomer fiber-based electro-rotating composite yarn is 600 twists / m.

[0097] Example 7

[0098] A preparation method of a liquid crystal elastomer fiber-based electro-rotating composite yarn, the specific steps are as follows:

[0099] (1) Preparation of spinning solution: the spinning solution is a mixture of RM257, EDDET, PETMP, HHMP, di-n-propylamine and acetone;

[0100] Among them, the molar ratio of RM257 to EDDET is 1:1, the molar ratio of RM257 to PETMP is 12:1, and the molar ratio of RM257 to acetone is 34:1. HHMP and di-n-propylamine each account for 2% of the total molar amount of the mixture;

[0101] (2) The improved wet spinning method is used, that is, the spinning solution is pre-crosslinked at room temperature for 30 min, and then extruded at a speed of 5 mm / min. The liquid crystal elastomer (LCE) fiber is prepared by ultraviolet point light source curing and shaping;

[0102] Among them, the diameter of the ultraviolet point light source is 0.8 cm, the power density is 2 mW / cm 2 , and the ultraviolet light irradiation time is the time required for the spinning solution to pass through the ultraviolet point light source at the extrusion speed;

[0103] (3) The improved ring spinning method is used, that is, the collected liquid crystal elastomer fiber and the gold-plated molybdenum wire are fed into the twisting device by the roller at a quantity ratio of 1:1. The twisting is completed by the rotation of the ring along the ring and the rotation of the sliver. The speed difference between the ring and the bobbin placed in the ultraviolet box without top makes the sliver wind onto the bobbin. The bobbin performs photopolymerization reaction during the rotation and twisting process, and the liquid crystal elastomer fiber-based electro-rotating composite yarn is prepared;

[0104] Among them, the ultraviolet light power density in the improved ring spinning ultraviolet box is 30 mW / cm 2The ultraviolet light irradiation time is 30 min; the rotating speed of the cylinder is 90 rpm, and the rotating speed of the steel ring is 12.1 m / min.

[0105] The prepared electro-rotating composite yarn based on liquid crystal elastomer fiber is a plying yarn held by one end of the gold-plated molybdenum wire and twisted at the other end. In one twist, the liquid crystal elastomer fiber and the gold-plated molybdenum wire rotate in the same direction around the fiber axis for one circle, and the relative positions are exchanged twice. The liquid crystal elastomer fiber and the gold-plated molybdenum wire in the plying yarn are extruded at the twist, and the friction force is obtained along the length direction of the fiber and the positions are interlocked to form a stable structure under the condition of ultraviolet light curing. The electro-rotating composite yarn based on liquid crystal elastomer fiber rotates forward under the voltage stimulation, and rotates reversely after the voltage stimulation is removed, and gradually restores the twist. The twist of the electro-rotating composite yarn based on liquid crystal elastomer fiber is 500 twists / m.

Claims

1. A method for the preparation of an electro-rotatory composite yarn based on liquid crystal elastomer fibers, characterized in that: The electro-rotating composite yarn based on liquid crystal elastomer fiber is a plying yarn formed by holding one end of the liquid crystal elastomer fiber and the flexible conductive yarn and twisting the other end, in one twist return, the liquid crystal elastomer fiber and the flexible conductive yarn rotate in the same direction around the fiber axis for one circle, and the relative positions are exchanged twice; the liquid crystal elastomer fiber and the flexible conductive yarn in the plying yarn are extruded at the twist return, and the friction force is obtained along the length direction of the fiber and the positions are interlocked to form a stable structure under the condition of ultraviolet curing; the liquid crystal elastomer fiber is prepared by using the improved wet spinning method, and then the liquid crystal elastomer fiber and the flexible conductive yarn are twisted by improving the ring spinning method to obtain the electro-rotating composite yarn based on the liquid crystal elastomer fiber. The improved wet spinning is to solidify and form after the spinning solution is extruded by a UV point light source; the diameter of the UV point light source is 0.8 cm, the power density is 2-5 mW / cm 2 , and the UV light irradiation time is the time required for the spinning solution to pass through the UV point light source at the extrusion speed; The improved ring spinning is to place a bobbin of a ring spinning device in a topless ultraviolet box, and the bobbin performs a photopolymerization reaction in the process of rotary twisting; the ultraviolet light power density in the ultraviolet box is 15-30 mW / cm 2 , and the ultraviolet light irradiation time is 30 min or more. The electro-rotating composite yarn based on liquid crystal elastomer fiber is positively rotated under the voltage stimulation and reversely rotated after the voltage stimulation is removed, and gradually restores the twist.

2. A method of producing an electro-rotatory composite yarn based on liquid crystal elastomer fibers according to claim 1, characterized in that, The spinning solution is a mixture of liquid crystal monomer, spacer, crosslinking agent, photoinitiator, catalyst and organic solvent, the molar ratio of the liquid crystal monomer to the spacer is 1-2:1, the molar ratio of the liquid crystal monomer to the crosslinking agent is 6-12:1, and the molar ratio of the liquid crystal monomer to the organic solvent is 34:1, the photoinitiator and the catalyst each account for 2% of the total molar amount of the mixture.

3. A method of producing an electro-rotatory composite yarn based on liquid crystal elastomer fibers according to claim 2, characterized in that, The liquid crystal monomer is an acrylate, the organic solvent is acetone, toluene or dichloromethane, the photoinitiator is HHMP or IG651, the spacer is EDDET, the crosslinking agent is PETMP, and the catalyst is di-n-propylamine.

4. A method of producing an electro-rotatory composite yarn based on liquid crystal elastomer fibers according to claim 3, characterized in that, The spinning solution is pre-crosslinked at room temperature for 15-30 minutes and then extruded at an extrusion speed of 3-5 mm / min.

5. A method of preparing an electro-rotatory composite yarn based on liquid crystal elastomer fibers according to claim 1, characterized in that, The specific process of twisting the liquid crystal elastomer fiber and the flexible conductive yarn by improving the ring spinning method is as follows: the collected liquid crystal elastomer fiber and flexible conductive yarn are fed into the twisting device through the roller, the rotation of the spindle makes the traveler rotate along the ring and drives the sliver to rotate to complete the twisting, and the speed difference between the traveler and the bobbin makes the sliver wind onto the bobbin.

6. A method of producing an electro-rotatory composite yarn based on liquid crystal elastomer fibers according to claim 5, characterized in that, The speed of the bobbin is 72-90 rpm, and the speed of the traveler is 9.7-12.1 m / min.

7. A method of making a liquid crystal elastomer fiber-based electro-rotatory composite yarn according to claim 1, characterized in that, The flexible conductive yarn is gold-plated molybdenum wire, nickel-titanium alloy wire, stainless steel wire, carbon nanotube yarn, carbon fiber yarn or silver-plated nylon yarn.

8. A method of making a liquid crystal elastomer fiber-based electro-rotatory composite yarn according to claim 1, characterized in that, The liquid crystal elastomer fiber and the flexible conductive yarn are twisted at a quantity ratio of 1:

1.

9. A method of making a liquid crystal elastomer fiber-based electro-rotatory composite yarn according to claim 1, characterized in that, The twist of the electro-rotating composite yarn based on the liquid crystal elastomer fiber is 300-1200 twists / m.

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