阅读说明：本技术 一种相变纤维的制备方法 (Preparation method of phase change fiber ) 是由 罗英武 赵玉海 高翔 于 2019-10-17 设计创作，主要内容包括：本发明公开一种相变纤维的制备方法,该方法利用RAFT细乳液界面聚合,制备得到亚微米相变胶囊水分散液,将其与纺丝原液直接混合,利用湿法纺丝,制备得到相变纤维。本发明制备得到的亚微米相变胶囊水分散液,其胶囊的芯材包覆量超过50wt％,胶囊的热焓值超过110J/g,胶囊的粒径小于1微米,实现了胶囊高包覆量与亚微米尺寸的统一。相变纤维结晶热和熔融热可超过20J/g,具有优良的调热性能；单根纤维直径小于50μm,具有较好的可编织性和舒适性。将亚微米相变胶囊水分散液与纺丝原液直接共混,可显著提高亚微米相变胶囊在相变纤维中的分散程度,使相变纤维的调热性能更加稳定,在智能纤维领域有巨大的应用前景。(The invention discloses a preparation method of phase change fiber, which comprises the steps of preparing submicron phase change capsule aqueous dispersion by RAFT miniemulsion interfacial polymerization, directly mixing the submicron phase change capsule aqueous dispersion with spinning stock solution, and preparing the phase change fiber by wet spinning. According to the submicron phase change capsule aqueous dispersion prepared by the invention, the coating amount of the core material of the capsule exceeds 50 wt%, the enthalpy value of the capsule exceeds 110J/g, and the particle size of the capsule is less than 1 micron, so that the unification of the high coating amount and the submicron size of the capsule is realized. The crystallization heat and the melting heat of the phase-change fiber can exceed 20J/g, and the phase-change fiber has excellent heat regulation performance; the diameter of each fiber is less than 50 μm, and the fiber has good weavability and comfortableness. The submicron phase change capsule aqueous dispersion is directly blended with the spinning solution, so that the dispersion degree of the submicron phase change capsules in the phase change fibers can be obviously improved, the heat regulation performance of the phase change fibers is more stable, and the submicron phase change capsule aqueous dispersion has a huge application prospect in the field of intelligent fibers.)

1. The preparation method of the phase change fiber is characterized by comprising the following operation steps of:

(1) and (3) putting 1 part by mass of dispersoid into 2-9 parts by mass of dispersion medium, raising the temperature to 60-95 ℃, and stirring for 0.1-4 hours to obtain spinning stock solution.

The submicron phase change capsule aqueous dispersion is prepared by the following steps:

(2) dissolving 0.01-0.5 part by mass of amphiphilic macromolecular RAFT emulsifier in 40-400 parts by mass of deionized water to obtain an aqueous phase.

(3) 0.01-0.5 part by mass of an oil-soluble initiator, 5-200 parts by mass of a core material and 1-100 parts by mass of a monomer are uniformly mixed to obtain an oil phase.

(4) And (3) mixing the water phase and the oil phase obtained in the step (a), and stirring and pre-emulsifying for 5-30 min to form a coarse emulsion. And (4) treating for 5-30 min by using shearing equipment to obtain the miniemulsion.

(5) And adding 0.01-0.2 part by mass of amphiphilic macromolecular RAFT emulsifier, introducing inert gas for 5-30 min, heating to 60-95 ℃, and reacting for 6-12 h to obtain the submicron phase change capsule water dispersion.

(6) Mixing 0.1-5 parts by mass of the submicron phase change capsule aqueous dispersion in the step (5) with 4-8 parts by mass of the spinning stock solution in the step (1) to form a mixed spinning solution;

(7) and (4) pressing the mixed spinning solution obtained in the step (6) into a coagulating bath through a spray head, and carrying out wet-heat stretching and dry-heat stretching processes to obtain the phase-change fiber.

2. The method according to claim 1, wherein in the step (1), the dispersoid is polyvinyl alcohol, a block copolymer of (styrene-N-butyl acrylate-styrene), a block copolymer of (styrene-butadiene-styrene) or polyacrylonitrile, and the dispersion medium is water, tetrahydrofuran, ethanol, toluene, methanol, diethyl ether, dimethyl sulfoxide, N-dimethylformamide or N, N-dimethylacetamide.

3. The method according to claim 1, wherein in the step (3), the coagulation bath is an aqueous sodium sulfate solution, an aqueous sodium thiocyanate solution, an aqueous sodium chloride solution, an aqueous magnesium sulfate solution, an ethanol-water mixture, an acetone-water mixture, N-dimethylformamide, or N, N-dimethylacetamide.

4. The method according to claim 1, wherein in the step (2), the amphiphilic macro RAFT emulsifier has a formula: r- (M)_n1-co-N_n2) -X or R- (M)_n1-b-N_n2)-X；

Wherein R is an isopropanoyl, acetoxy, 2-cyanoacetoxy or 2-aminoacetoxy group; m_n1Wherein M is a methacrylic acid monomer or an acrylic acid monomer unit, n1 is the average polymerization degree of M, and n1 is 5-100; n is a radical of_n2Wherein N is a styrene monomer, an N-butyl acrylate monomer, methyl acrylate, isooctyl acrylate or methyl methacrylate monomer unit, N2 is the average polymerization degree of N, and N2 is 5-100; the X group is an alkyl dithio ester group or an alkyl trithio ester group.

5. The production method according to claim 1, wherein in the step (3), the oil-soluble initiator is an azo initiator, a peroxide initiator; the core material is C₅～C₂₈Or a mixture thereof; the monomer is a vinyl-containing monomer.

6. The method of claim 5, wherein the vinyl-containing monomer is selected from the group consisting of methyl acrylate, styrene, n-butyl acrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, divinyl benzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, vinyl pyrrolidone, and triethylene glycol dimethacrylate.

Technical Field

The invention relates to the field of intelligent fibers, in particular to a preparation method of a phase change fiber.

Background

The phase-change fiber is a heat-storage temperature-regulating functional fiber developed by utilizing the characteristic that the phase-change material keeps the temperature unchanged by absorbing or releasing heat in the phase-change process. The fiber fabric automatically adjusts the internal temperature of the fabric according to the environmental temperature, and automatically increases the internal temperature of the fabric when the environmental temperature is low; when the environmental temperature is high, the temperature in the fabric is automatically reduced, so that the temperature in the fabric is in a more comfortable range.

The micro/nano capsule is a composite particle with a unique nano structure, and consists of a shell wall material with the thickness of one to tens of nanometers and a core material. The phase change capsule is a micro/nano capsule type with a phase change material as a core material, and can solve or relieve the problems of easy leakage, low heat conduction efficiency and the like of the phase change material in the using process. The method for preparing the phase-change temperature-regulating fabric by utilizing the microcapsules mainly comprises a microcapsule coating method, a microcapsule filling fabric method, a microcapsule spinning method and the like.

RAFT miniemulsion interfacial polymerisation is a novel process for the preparation of capsules combining RAFT living radical polymerisation and miniemulsion polymerisation. By self-assembling the amphiphilic macromolecular RAFT reagent on an oil drop/water phase interface formed by fine emulsification, the formed primary free radical can quickly carry out chain transfer reaction on the macromolecular RAFT reagent on the oil drop/water phase interface, and the generated new macromolecular free radical can be continuously anchored on the oil drop interface due to the fact that the amphiphilic nature of the generated new macromolecular free radical is still remained. This free radical will undergo a chain transfer reaction with the adjacent macro RAFT agent or a chain extension reaction with the monomer in the oil droplet, the reaction occurring repeatedly, so that the free radical is always at the oil droplet/water phase interface, thereby limiting the polymerisation reaction to occur only at the interface. As the polymerization reaction proceeds, the polymer chains grow from the outside inward, forming polymer walls in situ, while the core material remains in the core layer. The method overcomes the defect that the common miniemulsion can not prepare the polymer shell layer with uniform thickness and high crosslinking degree.

At present, although the coating amount of the fiber fabric prepared by a microcapsule method exceeds 50 wt%, the fiber fabric has certain heat regulating performance, but the fiber fabric is limited to a polymerization method, and the size of the prepared capsule is in micron order or even millimeter order, so that the fiber diameter is large, the thermal response speed is low, and the softness and the comfort degree are poor; whereas in miniemulsion polymerization and in existing RAFT miniemulsion interfacial polymerization systems, the coating amounts are much less than 50 wt%. Considering the practical application of the phase change fiber, the capsule coating amount is expected to exceed 50 wt% to provide more latent heat of phase change; and the particle size of the phase-change capsule is smaller than the micron level, so that a larger specific surface area is provided, the thermal response speed is high, and the heat-regulating fiber prepared further has a smaller diameter, so that the phase-change capsule has better softness and comfort.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the preparation method of the phase change fiber, and the prepared phase change fiber has better heat regulation performance and smaller diameter, has better performance in the aspects of comfort, knittability, mechanical strength and the like, and has huge application prospect in the field of intelligent fibers. The specific technical scheme is as follows:

a preparation method of phase change fiber comprises the following operation steps:

(1) putting 1 part by mass of dispersoid into 2-9 parts by mass of dispersion medium, raising the temperature to 60-95 ℃, and stirring

And (5) obtaining the spinning solution after 0.1-4 hours.

The submicron phase change capsule aqueous dispersion is prepared by the following steps:

(2) dissolving 0.01-0.5 part by mass of amphiphilic macromolecular RAFT emulsifier in 40-400 parts by mass of deionized water to obtain an aqueous phase.

(3) 0.01-0.5 part by mass of an oil-soluble initiator, 5-200 parts by mass of a core material and 1-100 parts by mass of a monomer are uniformly mixed to obtain an oil phase.

(4) And (3) mixing the water phase and the oil phase obtained in the step (a), and stirring and pre-emulsifying for 5-30 min to form a coarse emulsion. And (4) treating for 5-30 min by using shearing equipment to obtain the miniemulsion.

(5) And adding 0.01-0.2 part by mass of amphiphilic macromolecular RAFT emulsifier, introducing inert gas for 5-30 min, heating to 60-95 ℃, and reacting for 6-12 h to obtain the submicron phase change capsule water dispersion.

(6) Mixing 0.1-5 parts by mass of the submicron phase change capsule aqueous dispersion in the step (5) with 4-8 parts by mass of the spinning stock solution in the step (1) to form a mixed spinning solution;

(7) and (4) pressing the mixed spinning solution obtained in the step (6) into a coagulating bath through a spray head, and carrying out wet-heat stretching and dry-heat stretching processes to obtain the phase-change fiber.

Further, in the step (1), the dispersoid is polyvinyl alcohol, (styrene-N-butyl acrylate-styrene) block copolymer, (styrene-butadiene-styrene) block copolymer or polyacrylonitrile, and the dispersion medium is water, tetrahydrofuran, ethanol, toluene, methanol, diethyl ether, dimethyl sulfoxide, N-dimethylformamide or N, N-dimethylacetamide.

Further, in the step (3), the coagulating bath is an aqueous sodium sulfate solution, an aqueous sodium thiocyanate solution, an aqueous sodium chloride solution, an aqueous magnesium sulfate solution, an ethanol-water mixture, an acetone-water mixture, N-dimethylformamide or N, N-dimethylacetamide.

Further, in the step (2), the structural formula of the amphiphilic macromolecular RAFT emulsifier is as follows: r- (M)_n1-co-N_n2) -X or R- (M)_n1-b-N_n2)-X；

Wherein R is an isopropanoyl, acetoxy, 2-cyanoacetoxy or 2-aminoacetoxy group; m_n1Wherein M is a methacrylic acid monomer or an acrylic acid monomer unit, n1 is the average polymerization degree of M, and n1 is 5-100; n is a radical of_n2Wherein N is a styrene monomer, an N-butyl acrylate monomer, methyl acrylate, isooctyl acrylate or methyl methacrylate monomer unit, N2 is the average polymerization degree of N, and N2 is 5-100; the X group is an alkyl dithio ester group or an alkyl trithio ester group.

Further, in the step (3), the oil-soluble initiator is an azo initiator or a peroxide initiator; the core material is C₅～C₂₈Or a mixture thereof; the monomer is a vinyl-containing monomer.

Further, the vinyl-containing monomer is preferably composed of one or more monomers of methyl acrylate, styrene, n-butyl acrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate or vinyl pyrrolidone, triethylene glycol dimethacrylate in any proportion.

The method has the beneficial effects that the method can prepare the submicron phase-change capsule with the grain size less than 1 micron by utilizing RAFT miniemulsion interface polymerization; the coating amount of the submicron phase change capsule can be adjusted by changing the mass ratio of the core material to the monomer; the size of the phase-change capsule can be adjusted within the range of 100-1000nm by simply adjusting the dosage of the amphiphilic macromolecular emulsifier; when the size of the capsule is fixed, the larger the mass of the core material is, the smaller the mass of the monomer is, the more easily the shell layer collapses, and the higher coating amount is difficult to realize; when the size is increased, the interfacial tension of the shell layer wall material is reduced, the shell layer is not easy to collapse, and the submicron phase change capsule with high coating amount can be prepared. Directly blending the obtained submicron phase change capsule with high coating amount and spinning solution, pressing the mixed spinning solution into a coagulating bath through a spinning nozzle by utilizing wet spinning, and collecting fibers to a roller through wet-heat stretching and dry-heat stretching processes.

Has the following characteristics:

1. the method adopts RAFT miniemulsion interface polymerization technology, can simultaneously realize the preparation of capsules with high coating amount (>50 wt%) and small particle size (<1 μm), and the molecular weight of the shell polymer is controllable in the polymerization process, and the thickness of the shell layer of the obtained phase-change capsule is uniform.

2. By utilizing the microcapsule spinning method, the problems of easy falling of capsules in use, poor integral air permeability of the fabric, poor softness and the like caused by a microcapsule coating method and a microcapsule fabric filling method are solved; the high-coating-amount submicron capsule prepared by RAFT miniemulsion interfacial polymerization solves the problem of large particle size of the microcapsule prepared by other polymerization methods, so that the subsequently prepared phase-change fiber has better softness and comfort and faster thermal response speed.

3. The submicron phase change capsule water dispersion is directly blended with the spinning solution, so that the dispersion degree of the phase change capsules in the fiber is greatly improved, and the prepared phase change heat-regulating fiber has stable heat-regulating performance.

Drawings

FIG. 1 is a schematic representation of the molecular structure of an amphiphilic macromolecular RAFT emulsifier used in example 1 of the present invention;

FIG. 2 is a NMR chart of an amphiphilic macromolecular RAFT emulsifier used in example 1 of the present invention;

FIG. 3 is a diagram of the morphology of different coating amounts of submicron phase change capsules synthesized in examples 1-4 of the present invention;

FIG. 4 is a graph showing particle size distribution of different coating amounts of submicron phase change capsules synthesized in examples 1-4 of the present invention;

FIG. 5 is a graph of the crystallization heat and melting heat for different coating amounts of submicron phase change capsules synthesized in examples 1-4 of the present invention;

FIG. 6 is a schematic diagram of phase change thermal fibers prepared in example 1(a), example 5(b) and example 6 (c);

FIG. 7 is a graph showing crystallization heat and melting heat curves of the phase change thermal fibers prepared in examples 1, 5 and 6 of the present invention;

FIG. 8 is a mechanical drawing graph of the phase change thermal fibers prepared in examples 1, 5 and 6 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

The submicron phase change capsule aqueous dispersion is prepared by RAFT miniemulsion interfacial polymerization, and the operation steps are as follows:

(a) dissolving 0.01-0.5 part by mass of amphiphilic macromolecular RAFT emulsifier in 40-400 parts by mass of deionized water, and stirring for dissolving;

(b) mixing 0.01-0.5 part by mass of an oil-soluble initiator, 5-200 parts by mass of a core material and 1-100 parts by mass of a monomer, and stirring for dissolving;

(c) and mixing the water phase and the oil phase, and stirring and pre-emulsifying for 5-30 min to form a coarse emulsion. Treating for 5-30 min by using shearing equipment to obtain miniemulsion; the shearing device can adopt a cell crusher, a homogenizer and a high-speed shearing emulsifier, but is not limited to the above.

(d) And adding 0.01-0.2 part by mass of amphiphilic macromolecular RAFT emulsifier, introducing inert gas for 5-30 min, heating to 60-95 ℃, and reacting for 6-12 h to obtain the submicron phase change capsule water dispersion.

The coating amount of the submicron phase change capsule can be adjusted by changing the mass ratio of the core material to the monomer; the size of the phase-change capsule can be adjusted within the range of 100-1000nm by simply adjusting the dosage of the amphiphilic macromolecular RAFT emulsifier. When the size of the capsule is fixed, the larger the mass of the core material is, the smaller the mass of the monomer is, the higher the coating amount is, and the more easily the shell layer collapses; when the dosage of the amphiphilic macromolecular RAFT emulsifier is reduced, the size is increased, the interfacial tension of a shell wall material is reduced, the shell is not easy to collapse, and the submicron phase change capsule with high coating amount can be prepared.

The amphiphilic macro RAFT emulsifier used in the step (a) is prepared by dispersing small RAFT, M, N monomers into dioxane, methanol, ethanol, water or a mixture thereof, and polymerizing in one step, but is not limited thereto. Wherein the small molecule RAFT has the following structural characteristics: R-X; the amphiphilic macromolecular RAFT emulsifier has the following structural characteristics: r- (M)_n1-co-N_n2) -X or R- (M)_n1-b-N_n2)-X，

Wherein R is an isopropanoyl, acetoxy, 2-cyanoacetoxy or 2-aminoacetoxy group; m_n1Wherein M is a methacrylic acid monomer or an acrylic acid monomer unit, n1 is the average polymerization degree of M, and n1 is 5-100; n is a radical of_n2Wherein N is a styrene monomer, an N-butyl acrylate monomer, methyl acrylate, isooctyl acrylate or methyl methacrylate monomer unit, N2 is the average polymerization degree of N, and N2 is 5-100; the X group is an alkyl dithio ester group or an alkyl trithio ester group;

the oil-soluble initiator in the step (b) is an azo initiator or a peroxide initiator; the core material is C₅～C₂₈Or a mixture thereof; the monomer is a vinyl-containing monomer, and specifically comprises the following components: methyl acrylate, styrene, n-butyl acrylate, methyl methacrylate, butyl methacrylate, ethyl acrylate, hydroxyethyl acrylate, divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate or vinylpyrrolidone, triethylene glycol dimethacrylate or mixtures thereof.

The operation steps for preparing the phase change fiber by adopting the submicron phase change capsule water dispersion liquid are as follows:

(1) putting 1 part by mass of dispersoid into 2-9 parts by mass of dispersion medium, raising the temperature to 60-95 ℃, and stirring for 0.1-4 hours to obtain spinning stock solution;

(2) mixing 0.1-5 parts by mass of submicron phase change capsule aqueous dispersion with 4-8 parts by mass of spinning stock solution to form mixed spinning solution;

(3) pressing the mixed spinning solution into a coagulating bath through a spray head, and collecting the fibers by using a roller through wet-heat stretching and dry-heat stretching processes.

The spinning solution adopted in the step (1) contains polyvinyl alcohol, a (styrene-N-butyl acrylate-styrene) block copolymer, a (styrene-butadiene-styrene) block copolymer or polyacrylonitrile as a dispersoid, and water, tetrahydrofuran, ethanol, toluene, methanol, diethyl ether, dimethyl sulfoxide, N-dimethylformamide or N, N-dimethylacetamide as a dispersion medium.

The coagulating bath used in the step (3) is an aqueous solution of sodium sulfate, an aqueous solution of sodium thiocyanate, an aqueous solution of sodium chloride, an aqueous solution of magnesium sulfate, an ethanol-water mixture, an acetone-water mixture, N-dimethylformamide or N, N-dimethylacetamide.

The structure of the amphiphilic macromolecular RAFT emulsifier is determined by nuclear magnetic resonance hydrogen spectrum, the model of the apparatus is BRUKERAvance DMX 500, and the nuclear magnetic reagent is dimethyl sulfoxide (DMSO).

The monomer conversion rate of the submicron phase-change capsule is measured by a weighing method.

The appearance of the submicron phase change capsule is characterized by a JEOL JEMACRO-1230 transmission electron microscope, and the test voltage is 80 kilovolts.

The shapes of the submicron phase-change capsules and the phase-change fibers are represented by an SU-8010 scanning electron microscope, a sample is adhered to a sample table through conductive adhesive before testing, and gold spraying is carried out on the surface of the sample table for 90s in a vacuum atmosphere.

The particle size distribution of the submicron phase change capsule is obtained by drawing 100 sample points by Nano Measure software.

The phase change enthalpy values of the submicron phase change capsules and the phase change fibers are represented by a Differential Scanning Calorimeter (DSC), the type of the DSC-200 is shown, the temperature rise range during testing is-20-70 ℃, and the temperature rise rate is 10 ℃/min.

The mechanical tensile property of the phase change thermal fiber is tested by a Zwick/Roll Z020 type universal material testing machine, the testing temperature is 20 ℃, the tensile rate is 10mm/min, and each sample is repeated at least three times.