US 11,674,242 B2
Fabrication, application and apparatus of fibers with aligned porous structure
Hao Bai, Zhejiang (CN); Ying Cui, Zhejiang (CN); Yujie Wang, Zhejiang (CN); and Weiwei Gao, Zhejiang (CN)
Assigned to ZHEJIANG UNIVERSITY, Zhejiang (CN)
Filed by ZHEJIANG UNIVERSITY, Zhejiang (CN)
Filed on Mar. 13, 2020, as Appl. No. 16/817,630.
Application 16/817,630 is a continuation of application No. PCT/CN2018/096755, filed on Jul. 24, 2018.
Claims priority of application No. 201810004795.1 (CN), filed on Jan. 3, 2018; application No. 201810316005.3 (CN), filed on Apr. 10, 2018; and application No. 201810342589.1 (CN), filed on Apr. 17, 2018.
Prior Publication US 2020/0208303 A1, Jul. 2, 2020
Int. Cl. D01D 5/247 (2006.01); D01D 1/02 (2006.01); D01F 1/07 (2006.01); D01F 6/82 (2006.01); D03D 15/513 (2021.01); D03D 15/52 (2021.01)
CPC D01D 5/247 (2013.01) [D01D 1/02 (2013.01); D01F 1/07 (2013.01); D01F 6/82 (2013.01); D03D 15/513 (2021.01); D03D 15/52 (2021.01)] 4 Claims
OG exemplary drawing
 
1. A method of fabricating a fiber which is thermal-insulating at high temperature and fire-retardant, comprising:
(1) using a poly(amic acid) hydrogel for spinning, performing a directional freezing process during spinning, and collecting the frozen fiber, wherein the directional freezing process includes: the poly(amic acid) hydrogel passing through a freezing copper ring after being extruded from an extruder and water is frozen directionally in a direction of a temperature gradient under a temperature field;
(2) freeze-drying the frozen fiber to remove ice crystal and then obtain a fiber with aligned porous structure; and
(3) heating the fiber to realize a thermal imidization of poly(amic acid) into polyimide,
wherein the fiber is a polyimide porous fiber with an aligned and continuous through-hole along an axial direction.