The graphene nanoribbon (GNR)/carbon composite nanofiber yarns were prepared by electrospinning from poly(acrylonitrile) (PAN) containing graphene oxide nanoribbons (GONRs), and successive twisting and carbonization. The electrospinning process can exert directional shear force coupling with the external electric field to the flow of the spinning solution. During electrospinning, the well-dispersed GONRs were highly oriented along the fiber axis in an electrified thin liquid jet. The addition of GONRs at a low weight fraction significantly improved the mechanical properties of the composite nanofiber yarns. In addition, the carbonization of the matrix polymer enhanced not only the mechanical but also the electrical properties of the composites. The electrical conductivity of the carbonized composite yarns containing 0.5 wt % GONR showed the maximum value of 165 S cm(-1). It is larger than the maximum value of the reported electrospun carbon composite yarns. Interestingly, it is higher than the conductivities of both the PAN-based pristine CNF yarns (77 S cm(-1)) and the monolayer GNRs (54 S cm(-1)). These results and Raman spectroscopy supported the hypothesis that the oriented GONRs contained in the PAN nanofibers effectively functioned as not only the 1-D nanofiller but also the nanoplatelet promoter of stabilization and template agent for the carbonization.
of the original manuscript: Matsumoto, H.; Ishiguro, T.; Konosu, Y.; Minagawa, M.; Tanioka, A.; Richau, K.; Kratz, K.; Lendlein, A.:
Shape-memory properties of electrospun non-woven fabrics prepared from degradable polyesterurethanes containing poly(Omega-pentadecalactone) hard segmentsIn: European Polymer Journal (2012) Elsevier Abstract Microscaled non-woven fabrics with fiber diameters in the range 1.8-3.1 m were prepared by electrospinning from a chloroform solution of a degradable multiblock copolymer (PDLCL) consisting of crystallizable poly(-pentadecalactone) hard segments (PPDL) and poly(-caprolactone) switching segments (PCL). The surface morphology and microstructure of the non-woven fabrics were characterized by scanning electron microscopy, temperature-controlled scanning probe microscopy, wide angle X-ray diffraction (WAXD), and small angle X-ray scattering (SAXS). The microstructural analysis demonstrated that the rod-like domains of hard segment (PPDL) formed in the electrospun PDLCL fiber functioned as physical crosslinks. Cyclic, thermomechanical tensile tests showed that the 10 m 100 nm PCL crystal
PPDL crystalGraphical abstract for the table of contents
Multiwalled carbon nanotube (MWNT)/poly(vinyl butyral) (PVB) composite nanofibers were prepared by electrospinning, successive twisting and heat treatment. The MWNTs were highly oriented in an electrified thin jet during electrospinning. The heat treatment of the twisted electrospun nanofiber yarns produced the characteristics of the CNT in the composite nanofiber yarns and enhanced their electrical properties, mechanical properties, and thermal properties. The electrical conductivity of the heated yarn was significantly enhanced and showed the maximum value of 154 S cm(-1) for the yarn heated at 400 °C. It is an order of magnitude higher than other electrospun CNT composite materials. These results demonstrated that the novel top-down process based on electrospinning, twisting, and heat treatment provide a promising option for simple and large-scale manufacture of CNT assemblies.
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