Highly strong and highly tough electrospun polyimide/polyimide composite nanofibers from binary blend of polyamic acids

Abstract

Electrospun blend-polyimide (blend-PI) nanofibers with high tensile strength and toughness are highlighted in this article. The blend-PI nanofibers were prepared by electrospinning the binary blend of rigid and flexible polyamic acids, followed by thermal imidization. The method is simple and can be extended to other kinds of polyamic acids. The morphologies and structures of the blend-PI nanofibers were investigated by scanning electron microscopy (SEM) and wide-angle X-ray diffraction (XRD). The mechanical properties, thermal properties and miscibility of the blend-PI nanofibers were studied by a tensile test, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The mechanical properties of the blend-PI nanofibers, including tensile strength, modulus, elongation at break and toughness, could be well-tuned by modifying the molar ratio of the rigid component (B-PI) and the flexible component (O-PI). The blend-PI nanofibers with B-PI/O-PI molar ratio of 4/6 had an ultra-high strength of 1.3 GPa with an excellent toughness of 82 J g À1 . All the blend-PI nanofibers showed thermal stability to above 500 C. The presence of only one glass transition temperature (T g ) suggested the good miscibility of the binary PIs in the blend-PI nanofibers. This study would provide completely new opportunities for modifying the properties of electrospun PI nanofibers.

Electrospun nanofiber reinforced all-organic PVDF/PI tough composites and their dielectric permittivity

“…Previous work found that the electrospun PI nanofibers possessed excellent mechanical strength [13], superior thermal stability [14], and super high toughness [13], which made them excellent candidates as reinforcements [15,16] and the layer-by-layer hot pressing can improve the uniformity and reduce the porosity of polymer-based composites [17][18][19]. Therefore, in this work, we choose high performance electrospun copolyimide (co-PI) nanofibers as reinforcement and high dielectric performance PVDF as matrix to prepare nanofiber reinforced all-organic composites.…”

Rapid formation of polyimide nanofiber membranes via hot-press treatment and their performance as Li-ion battery separators

“…Both PI membranes exhibited a much higher stress than the neat PAA membrane, $29 kgf cm À2 , due to imidization. 15,[30][31][32] In particular, the hotpress-induced PI membrane ($220 kgf cm À2 ) displayed a notably increased stress compared to the thermally-treated PI membranes ($107 kgf cm À2 ). This higher value for the mechanical property could be explained by the dense packing of the nanober layers and the inter-nanober interactions, as briey mentioned above.…”

Tunable Triple‐Shape Memory Binary Mixtures with High Transition Temperature and Robust Mechanical Properties

“…When compared to neat films of rigid PIB with high modulus and flexible PIO with high elongation, the blend PI (at the 7/3 molar ratio of PIB and PIO) not only possessed a higher strength but also a higher elongation. Previous studied have demonstrated that intermolecular interactions play a more important role in the improvement of the mechanical properties . Thus, changes in the intermolecular interactions, such as π–π stacking, crystallinity, and macromolecular orientation, will result in tremendous changes in mechanical properties.…”