Effect of high-pressure vapor on the microstructure and mechanical properties of TiO2 continuous fibers

During the preparation of TiO2 continuous fibers, the organic ligands of the precursor fibers are severely decomposed and generated a large amount of gas, which can reduce the fiber matrix strength. Tt is necessary to choose a suitable treatment strategy to avoid this and obtain high-quality TiO2 continuous fibers. In this study, flexible continuous TiO2 fibers with a diameter of about 30 mu m were prepared using a high-pressure vapor pretreatment method. The high-pressure vapor pretreatment caused precursor hydrolysis, which promoted the decomposition of the organic ligands in a mild way and prevented fiber fracture caused by the violent oxidative decomposition. The crystallization temperature decreased by 120 degrees C because of the synergistic effects of vapor and pressure. The hydrolysis of the precursor and the reduction in the crystallization temperature were conducive to the formation of compact fibers with high strength. However, the presence of water vapor caused the fibers to undergo the dissolution-precipitation process simultaneously, forming a large number of defects, which was harmful to its strength. The sample 1501 composed of anatase and rutile showed the highest average tensile strength of 385 MPa because it had fewer defects than the other samples. Although the highest average tensile strength is lower than the reported value of 800 MPa, the method is easy to implement and solves the problem of organics decomposition, which is helpful for industrial preparation.

Automated summary

During the preparation of TiO2 continuous fibers, the use of high-pressure vapor pretreatment method can prevent fiber matrix strength reduction caused by the severe decomposition of organic ligands. The vapor pretreatment promotes precursor hydrolysis and reduces crystallization temperature, leading to the formation of compact fibers with high strength. However, the presence of water vapor can also cause the formation of defects in the fiber structure.