Preparation of High-Quality Zirconia Fibers by Super-High Rotational Centrifugal Spinning of Inorganic Sol

Abstract

A novel inorganic sol-gel method for preparation of high-quality zirconia fibers was proposed, with starting from the reaction between ZrOCl 2 Á 8H 2 O (ZOC) and H 2 O 2 . The spinning solution with good spinnability was obtained by controlling the mole ratio of H 2 O 2 /ZOC to 4 for reaction, and the mole ratio of Cl/Zr remained close to 1 in the reacted solution. The double chain structure of the inorganic polyzirconium molecule in the spinning solution was determined by elemental analysis and FT-IR. The precursor fibers were obtained by using a novel 30,000 rpm centrifugal spinning apparatus. Being heat-treated to 1300 C under steam atmosphere, the precursor fibers transformed to zirconia fibers which had relatively high strength and good flexibility, with length of more than 10 cm and diameters of 5-10 mm.

Fabrication of Zirconia Fibers by a Sol-Gel Combined Rotational Centrifugal Spinning Technique

“…7 It indicates that the OH groups are not the dissociated OH groups, but associated with Zr 4+ to form a Zr-OH-Zr chain polymer. 8 The absorption peak at 1628 cm -1 is attributed to the H 2 O bending vibration. The absorption peaks at 1556, 1456, 1352, 1032, 954 and 647 cm -1 are attributed to the bending vibration of the functional groups of CH 3 COOH, which can prove the joint of CH 3 COO -and Zr 4+ .…”

“…14 After the initial hydrolysis process, tetramer complex [Zr 4 (OH) 8 16 ] 8+ was formed as a major species. The four zirconium atoms in each tetramer complex are arranged in a square, and each zirconium atom is coordinated by four bridging OH groups and four H 2 O molecules.…”

“…15 The tetramer complexes release H + ions from the coordinated water by deprotonation as described in Eqn (1), 16 Further hydrolysis processes were prevented by H + and Cl -.With the addition of proper degree of H 2 O 2 , Cl -can be removed from the solution, as shown in Eqn (2). When Cl -was removed, the same amount of -OH group was produced, and [Zr 4 (OH) 8 …”

“…2 The main methods of making zirconia fibers are: 3 impregnation of organic polymer fibers with zirconium salt solutions; 4 spinning of organic polymer fibers from polymer solutions containing zirconium salts or fine zirconia powders; 5, 6 spinning of sol solutions prepared by sol-gel processing of inorganic zirconium salt or zirconium alkoxide. 7,8 The present spinning techniques for preparing zirconia fibers include rotational centrifugal spinning, dry spinning, blow spinning and electrospinning. Rotational centrifugal spinning can meet the mass production requirement of zirconia fibers due to its fiberizing efficiency.…”

Rheological behavior, molecular structure of precursor and evolution mechanism: zirconia fibers from polyaceticzirconium precursors

“…In the above-mentioned synthetic process, triethylamine was added to remove chloride ion (Cl -) with formation of triethylamine hydrochloride, and therefore, the synthetic process is somewhat complicated. Recently, Liu et al [18] used ZOC and hydrogen peroxide (H 2 O 2 ) as raw materials for preparation of zirconia fibers. The Cl -of ZOC was oxidized to Cl 2 gas with the addition of H 2 O 2 , which is detrimental to environment and unsuitable for industrialscale application.…”