Solar reflective fibers with particle-in-void pores and preparation method for fabric thereof

Abstract

A polymer-based composite fiber includes a matrix including one or more polymers, a plurality of voids formed in the matrix, and a plurality of solid particles, each particle of the plurality of solid particles being disposed in a respective void of the plurality of voids. The fiber may have an aspect ratio of at least 10, the fiber aspect ratio being defined as the length of the fiber divided by the diameter of the fiber. Each void of the plurality of voids may have a respective long axis, each long axis being a line that extends through a longest dimension of the void, and each long axis may extend in a direction parallel to the length of the fiber.

1 . A polymer-based composite fiber comprising:
 a matrix comprising one or more polymers;   a plurality of voids formed in the matrix; and   a plurality of solid particles, each particle of the plurality of solid particles being disposed in a respective void of the plurality of voids;   wherein each void of the plurality of voids has a respective long axis, each long axis corresponding to a line that extends through a longest dimension of the void; and   wherein each long axis extends in a direction parallel to a length of the fiber.   
     
     
         2 . The polymer-based composite fiber of  claim 1 , wherein each void of the plurality of voids has an interior space, each interior space being isolated from an ambient environment. 
     
     
         3 . The polymer-based composite fiber of  claim 1 , wherein each void of the plurality of voids has a void interior surface, and wherein each particle of the plurality of solid particles is completely encapsulated by a respective void interior surface. 
     
     
         4 . The polymer-based composite fiber of  claim 1 , wherein each void has an aspect ratio of at least 3, the void aspect ratio being defined as the longest dimension of a respective void divided by a width of the void. 
     
     
         5 . The polymer-based composite fiber of  claim 4 , wherein for each respective void of the plurality of voids, the width of the void is less than or equal to an effective diameter of the particle disposed within the void. 
     
     
         6 . The polymer-based composite fiber of  claim 5 , wherein for each respective void, the particle is disposed in the void such that the particle divides the void into two separate sub-voids. 
     
     
         7 . The polymer-based composite fiber of  claim 1 , wherein the diameter of the fiber is selected from the range of 100 nm to 1000 microns. 
     
     
         8 . The polymer-based composite fiber of  claim 1  having a ratio of a weight of the plurality of particles to a weight of the matrix of 5% to 50%. 
     
     
         9 . The polymer-based composite fiber of  claim 1  having a porosity in the range of 10% to 50%. 
     
     
         10 . The polymer-based composite fiber of  claim 1 , wherein the plurality of solid particles comprises polyolefin, aluminium oxide (Al2O3), silicon dioxide (SiO2), barium sulfate (BaSO4), zinc oxide (ZnO), boron nitride (BN), yttrium oxide (Y2O3), zirconium oxide (ZrO2), titanium dioxide (TiO2), zinc sulfide (ZnS), magnesium oxide (MgO), and/or ytterbium oxide (Yb2O3). 
     
     
         11 . The polymer-based composite fiber of  claim 1 , wherein the plurality of solid particles comprises polyolefin particles having an effective diameter in the range of 30 to 5000 μm. 
     
     
         12 . The polymer-based composite fiber of  claim 1 , wherein the plurality of solid particles comprises particles having an effective diameter in the range of 0.1 to 100 μm. 
     
     
         13 . The polymer-based composite fiber of  claim 1 , wherein the linear density of the fiber is in the range of 1 denier to 200 denier and the diameter of the fiber is in the range of 10 to 1000 μm. 
     
     
         14 . The polymer-based composite fiber of  claim 1 , wherein the fiber has an aspect ratio of at least 10, the fiber aspect ratio being defined as the length of the fiber divided by a diameter of the fiber. 
     
     
         15 . The polymer-based composite fiber of  claim 1 , wherein the polymer-based composite fiber is part of a fabric. 
     
     
         16 . A method of producing a solar reflective, polymer-based composite fiber, the method comprising:
 mixing a plurality of particles and a polymer material at a preset ratio to prepare a composite master batch;   heating the composite master batch to melt the polymer material of the composite master batch without melting the plurality of particles;   forming the melted composite master batch into a precursor composite fiber, the precursor composite fiber comprising at least some of the plurality of particles surrounded by a matrix of the polymer material; and   drawing the precursor composite fiber, thereby forming the solar reflective, polymer-based composite fiber, wherein the drawing comprises:
 elongating the precursor composite fiber such that a plurality of voids are formed in the fiber via the particles in the fiber. 
   
     
     
         17 . The method of  claim 16 , wherein the forming step comprises melt spinning the melted composite master batch to form the precursor composite fiber. 
     
     
         18 . The method of  claim 16 , wherein the heating step comprises heating the polymer to a temperature in the range of of 100 to 400° C. 
     
     
         19 . The method of  claim 16 , wherein the drawing step comprises drawing the precursor composite fiber at a draw ratio in the range of of 2 to 6. 
     
     
         20 . The method of  claim 16 , wherein the solar reflective, polymer-based composite fiber has an aspect ratio of at least 10, the fiber aspect ratio being defined as a length of the fiber divided by a diameter of the fiber;
 wherein each void of the plurality of voids has a respective long axis, each long axis being a line that extends through a longest dimension of the void; and   wherein each long axis extends in a direction parallel to the length of the fiber.   
     
     
         21 . A method of fabricating a cooling fabric, the method comprising:
 producing a plurality of solar reflective, polymer-based composite fibers, wherein producing a respective solar reflective, polymer-based composite fiber of the plurality of solar reflective, polymer-based composite fibers comprises:   mixing a plurality of particles and a polymer material at a preset ratio to prepare a composite master batch;   heating the composite master batch to melt the polymer material of the composite master batch without melting the plurality of particles;   forming the melted composite master batch into a precursor composite fiber, the precursor composite fiber comprising at least some of the plurality of particles surrounded by a matrix of the polymer material; and   drawing the precursor composite fiber, thereby forming the solar reflective, polymer-based composite fiber, wherein the drawing comprises: elongating the precursor composite fiber such that a plurality of voids are formed in the fiber via the particles in the fiber; and   weaving or knitting the solar reflective, polymer-based composite fibers into the cooling fabric.