CN-121992517-A - Radiation refrigeration fiber with anisotropic radial long pore canal and preparation method and application thereof

CN121992517ACN 121992517 ACN121992517 ACN 121992517ACN-121992517-A

Abstract

The invention relates to the technical field of functional textile materials, in particular to a radiation refrigeration fiber with anisotropic radial long pore canals, a preparation method and application thereof, wherein the preparation method mainly comprises the steps of blending and spinning a polymer matrix and a diluent, and carrying out phase separation through cold air induction; and drying and specific preheating and shaping treatment, and high-magnification directional drafting in the high-elastic state region of the polymer. The process induces the controlled plastic stretching and merging of micropores in the fiber to finally form an anisotropic strip-shaped pore structure which extends along the axial height and is radially arranged. The fiber prepared by the invention uses the axial continuous radial polymer wall as a bearing framework, so that the high-efficiency anisotropic scattering and heat insulation of sunlight are realized through the high-length-diameter-ratio pore canal while the breaking strength and the structural stability of the fiber are greatly improved.

Inventors

GAO TINGTING
XU XUE
LI YIJU
WANG QINYAN
LI FAXUE
YU JIANYONG

Assignees

东华大学

Dates

Publication Date: 20260508
Application Date: 20260213

Claims (9)

1. The preparation method of the radiation refrigeration fiber with the anisotropic radial long-strip pore canal is characterized by comprising the following steps of: S1, blending a polymer matrix and a diluent according to a preset mass-volume ratio, carrying out extrusion spinning at a temperature higher than the cloud point of the blend of the polymer matrix and the diluent, enabling the system to reach thermodynamic homogeneous phase by utilizing a double-screw shearing action, extruding a melt through a spinneret, and carrying out phase separation under the induction of cold air to form a nascent fiber with micro-nano diluent phase region distribution; s2, immersing the nascent fibers in an extractant, replacing and removing a diluent phase by utilizing a solvent diffusion effect at an extraction temperature, and leaving a micro-porous network skeleton corresponding to the morphology of a primary phase region in situ in a polymer matrix along with the removal of diluent molecules; s3, drying the fiber at a drying temperature for a preset drying time to remove residual extractant and eliminate the stress influence of the solvent on the microporous structure, so that the porous skeleton enters a physical steady state; S4, preheating and shaping the dried porous fiber at a preset temperature to enable the polymer skeleton to complete primary secondary crystallization so as to improve the radial compressive strength of the hole wall; And S5, carrying out high-rate directional drafting on the porous fiber after the preheating and shaping treatment at a drafting temperature, and inducing the controlled plastic stretching and merging of micropores in the fiber under the action of an axial stretching stress field to enable the pore channels to extend along the axial direction of the fiber and radially arrange the pore channels to form an anisotropic radial strip-shaped pore structure, wherein the drafting multiple of the high-rate directional drafting is 4-8 times.
2. The method for preparing the radiation refrigeration fiber with the anisotropic radial long pore canal according to claim 1, wherein the drying time in the step S3 is controlled to be 6-10 hours, the residual solvent in deep micropores inside the fiber is ensured to completely escape through the treatment of the time length, and the microscopic residual stress on the surface of the pore wall is eliminated, so that a basic condition is provided for the regular evolution of the pore canal in the subsequent directional drafting process.
3. The method for preparing radiation refrigeration fiber with anisotropic radial long pore canal according to claim 1, wherein the temperature of the preheating and shaping treatment in the step S4 is set above the cold crystallization peak temperature of the polymer matrix and 20-30 ℃ lower than the initial melting temperature of the polymer matrix; The preheating and shaping treatment time is 15-20 minutes, and in the temperature and time interval, the polymer molecular chain segments have enough motion capability to induce secondary crystallization and platelet thickening of the polymer framework, so that the strength of the microporous wall against high-power stretching radial centripetal force is improved, and the polymer primary melting area is avoided to prevent micropores from retracting or closing.
4. The method for preparing radiation refrigeration fiber with anisotropic radial long pore canal as claimed in claim 1, wherein the drawing temperature in the step S5 is in the high-elastic state region of the polymer matrix, and the temperature is 30-50 ℃ lower than the melting point of the polymer matrix, so as to ensure that the polymer chain segment has the movement capability of inducing the pore canal to generate axial orientation and provide the melt strength for supporting the radial skeleton.
5. The method for preparing radiation refrigeration fiber with anisotropic radial long pore canal as claimed in claim 1, wherein in the step S5, the initial micropores are induced to be axially oriented by using the oriented stress field of the high-magnification oriented draft magnification interval and the aspect ratio of the micropores is improved, so that the originally isolated punctiform pores are evolved into continuous linear pores; The draft multiple is used for forming a long strip-shaped pore canal with the length-diameter ratio of 50-300, and simultaneously inducing the polymer matrix to generate crystallization orientation, so as to form a composite reinforced structure of a continuous pore wall and an oriented molecular chain.
6. The preparation method of the radiation refrigeration fiber with the anisotropic radial long pore canal is characterized in that the polymer matrix is one or more of polypropylene, polylactic acid, polyamide and polyester, the diluent is one or more of liquid paraffin, dibutyl phthalate, dioctyl phthalate, oleic acid, stearic acid, gluconolactone, triethyl citrate, diethylene glycol and caprolactam, the extractant is one or more of ethanol, isopropanol, n-propanol, n-hexane, n-heptane, petroleum ether, acetone, butanone and ethyl acetate, and the mass volume ratio of the polymer matrix to the diluent is 1-2:1.
7. A radiation refrigeration fiber with anisotropic radial long-strip pore canal, characterized in that the fiber is prepared by the method of any one of claims 1 to 6, and the fiber has a structure with an axially continuous radial polymer wall as a bearing framework inside; The pore canal inside the fiber presents an anisotropic strip-shaped pore structure which extends along the axial height and is radially arranged, the length-diameter ratio of the strip-shaped pore is 50-300, and the structure forms a longitudinal micro-groove on the surface of the fiber.
8. A radiation refrigeration fiber having anisotropic radial elongated channels according to claim 7, wherein said elongated channels of said fiber form multiple reflective interfaces, whereby normally incident light is scattered sideways by anisotropic scattering to enhance solar reflectance, while said longitudinal micro-grooves impart a directional moisture guiding function to the fiber based on capillary effect.
9. Use of a radiation refrigerant fiber with anisotropic radial elongated channels as claimed in claim 7 or 8 for the preparation of personal thermal management textiles.

Description

Radiation refrigeration fiber with anisotropic radial long pore canal and preparation method and application thereof Technical Field The invention relates to the technical field of functional textile materials, in particular to a radiation refrigeration fiber with anisotropic radial long pore canals, a preparation method and application thereof. Background With the continuous acceleration of global industrialization, the global warming problem caused by greenhouse gas emission has become increasingly serious, which not only results in a significant increase in refrigeration energy consumption, but also greatly increases the heatstroke risk faced by outdoor workers. Under the background, a passive radiation refrigeration technology is widely paid attention as an emerging thermal management scheme, and the technology achieves a net cooling effect without external energy input by emitting thermal radiation to an outer space in an atmospheric window band and simultaneously reflecting heat in a solar spectrum band, and has great application potential in the aspects of relieving energy crisis and improving personal thermal comfort. Although researchers have attempted to develop flexible radiant refrigerant materials through a variety of paths, the prior art solutions still present a number of bottlenecks in practical use. For example, the invention patent CN202410617640.0 discloses a method for preparing a radiation refrigeration coated fabric by a pregelatinization process, which realizes a better refrigeration effect through a cellulose acetate skeleton and a pore-forming agent, but the introduction of the coating tends to block the pores of the fabric, so that the air permeability and the moisture permeability are poor, and the human body taking experience is seriously affected, the invention patent CN202510043718.7 adopts a fiber membrane prepared by an electrostatic spinning technology, which realizes high solar reflectance through the high porosity of superfine fibers, but the membrane structure formed by unordered stacked fibers lacks a macroscopic bearing skeleton, has low mechanical strength and is difficult to resist abrasion and stretching in daily wearing, the invention patent CN202010261960.9 adopts a composite melt spinning mode of a polymer substrate and inorganic micro-nano particles, and the invention CN202010261960.9 adopts a scattering effect of inorganic particles, so that the high reflectivity is realized, but the high doping amount can destroy the polymer continuity, so that the fiber strength is greatly reduced and the abrasion and the silk spraying equipment are easily affected, and in addition, the porous structure is introduced by a foaming technology, refrigeration and heat insulation can be realized, the formed punctiform fracture structure is extremely easy to generate stress concentration when the stress is stressed, so that the fiber fracture strength is easy to generate low, and the cell collapse is easily generated under the cyclic irreversible load. In summary, the existing radiation refrigeration textile has the obvious defects of high strength and function contradiction, such as low physical strength of a fiber membrane and stress concentration caused by inorganic particle doping or random porous structure, so that the fiber is easy to be broken and short in service life, unbalance of cooling and comfort, loss of air and moisture permeability functions of the textile due to the coating technology, poor structural stability, and easy collapse of randomly distributed foam holes after being stressed, and refrigeration effect attenuation along with use time. Therefore, developing a radiation refrigeration fiber with high mechanical strength, excellent refrigeration performance and good moisture-conducting comfort is a technical problem to be solved currently. Disclosure of Invention Aiming at the defects of the prior art, the invention provides the radiation refrigeration fiber with the anisotropic radial long pore canal, and the preparation method and the application thereof, and solves the problems of low mechanical strength, easy collapse of the structure and missing of the moisture-conducting function of the radiation refrigeration fiber in the prior art. The preparation method of the radiation refrigeration fiber with the anisotropic radial long-strip pore canal comprises the following steps: S1, blending a polymer matrix and a diluent according to a preset mass-volume ratio, carrying out extrusion spinning at a temperature higher than the cloud point of the blend of the polymer matrix and the diluent, enabling the system to reach thermodynamic homogeneous phase by utilizing a double-screw shearing action, extruding a melt through a spinneret, and carrying out phase separation under the induction of cold air to form a nascent fiber with micro-nano diluent phase region distribution; s2, immersing the nascent fibers in an extractant, replacing and removing a diluent phase by uti