Preparation of nonwoven polyimide/silica hybrid nanofiberous fabrics by combining electrospinning and controlled in situ sol–gel techniques

• Published in: European polymer journal 2009-10, Vol.45 (10), p.2767-2778
• Main Authors: Cheng, Si, Shen, Dezhi, Zhu, Xinsheng, Tian, Xingguang, Zhou, Dongying, Fan, Li-Juan
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; Electrospinning; Exact sciences and technology; Forms of application and semi-finished materials; In situ sol–gel; Nanofiberous fabrics; Polyimide/silica hybrids; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2009.06.021

A controlled in situ sol–gel synthesis combined with the electrospinning technique and postspun imidization was applied in the fabrication of polyimide/silica hybrid nonwoven nanofiberous fabrics with excellent thermal and mechanical performance. The nanofiberous fabrics were prepared by electrospinning of the solution of tetraethoxysilane (TEOS) and polyamic acid (PAA). The different silica contents in the fabrics were achieved by varying the amount of TEOS while fitting the solid content of PAA. The final polyimide/silica fabrics was obtained after imidization of PAA and gelation of silica phase simultaneously accomplished through a step-wise heating process. Some specific IR techniques and other characterizations indicated the successful incorporation of the silicon dioxide (SiO 2) into the PI matrix and the relatively even distribution of the SiO 2 in the fabrics. An increase of 133 °C in the decomposition temperature and 4-fold enhancement of the ultimate tensile strength were achieved for the hybrids with a 6.58 wt.% of SiO 2 content, compared to the pure PI fabric. The excellent performance could be attributed to the good compatibility between the polyimide and silica, and good adhesion among the fibers, which resulted from the controlled TEOS hydrolysis and the simultaneous imidization and gelation process.