Synthesis and properties of novel polyimide fibers containing phosphorus groups in the side chain (DATPPO)

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• 作者：Yong Zhao ; Guo-min Li ; Fang-fang Liu ; Xue-min Dai…
• 关键词：[2 ; 5 ; Bis(4 ; aminophenoxy) phenyl] diphenylphosphine oxide ; Dry ; jet wet spinning process ; Phosphorous ; Polyimide fibers
• 刊名：Chinese Journal of Polymer Science
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：35
• 期：3
• 页码：372-385
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Polymer Sciences; Industrial Chemistry/Chemical Engineering; Characterization and Evaluation of Materials; Condensed Matter Physics;
• 出版者：Chinese Chemical Society and Institute of Chemistry, CAS
• ISSN：1439-6203
• 卷排序：35

文摘

A series of polyamic acid copolymers (co-PAAs) containing phosphorous groups in the side chains were synthesized from [2,5-bis(4-aminophenoxy) phenyl] diphenylphosphine oxide (DATPPO) and 4,4′-oxydianiline (ODA) with 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) through the polycondensation in N,N′-dimethyacetamide (DMAc). The co-PAA solutions were spun into fibers by a dry-jet wet spinning process followed by thermal imidization to obtain co-polyimide (co-PI) fibers. FTIR spectra and elemental analysis confirmed the chemical structure of PI fibers. SEM results indicated that the resulting PI fibers had a smooth and dense surface, a uniform and circle-shape diameter. The thermogravimetric measurements showed that with the increase of DATPPO content, the resulting PI fibers possessed high decomposition temperature and residual char yield, indicating that the PI fibers had good thermal stability. The corresponding limiting oxygen index (LOI) values from the experiment results showed that the co-PI fibers possessed good flame-retardant property. Furthermore, the mechanical properties of the co-PI fibers were investigated systematically. When the DATPPO content increased, the tensile strength and initial modulus of the co-PI fibers decreased. However, the mechanical properties were improved by increasing the draw ratio of the fibers. When the draw ratio was up to 2.5, the tensile strength and initial modulus of the co-PI fibers reached up to 0.64 and 10.02 GPa, respectively. The WAXD results showed that the order degree of amorphous matter increased with increased stretching. In addition, the SAXS results displayed that valuably drawing the fibers could eliminate the voids inside and lead to better mechanical property. WAXD revealed that the orientation of the amorphous polymer influenced the mechanical properties of the fibers.