Abstract
Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection.The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains.In this work,crosslinked polyimide fibers(CPI fibers)were pro-duced by intrinsic carboxyl decarboxylation for the first time.The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers)was studied,and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃.The PIC fibers were hot-drawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature.The CPI fibers had high tensile strengths(0.72-1.46 GPa)and compressive strengths(401-604 MPa).The oriented macromolecules and chemically crosslinked structure im-proved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance.The CPI-50 fiber did not dissolve in a 0.5 wt％NaOH solution during heating at 90 ℃ for 10 h,and the tensile strength retention reached 87％when treated in 0.5 wt％NaOH solu-tions at 90 ℃ for 1 h,providing a guarantee for its application in alkaline corrosive environments.
基金项目
Scientific Research Innovation Plan of Shanghai Education Commission(2019-01-07-00-03-E00001)
National Natural Science Foundation of China(U21A2087)
National Natural Science Foundation of China(21975040)
Natural Science Foundation of Shanghai(21ZR1400200)
维普
万方数据