Customizing fiber spinning approaches for polymer/nano-carbon composites.

摘要

Among the many potential applications of nano-carbon (nC), their ability to improve stiffening, strengthening, and toughening mechanisms in polymeric materials has been given considerable attention due to the excellent mechanical properties, and low density of these graphitic materials. The approaches toward designing composites have provided numerous opportunities for the invention of new materials for applications requiring high-strength and high-modulus. Precise control of processing factors including (i) preserving intact nC structure, (ii) uniform dispersion of the nC in polymers, (iii) effective filler-matrix interfacial interactions, and (iv) alignment/orientation of the nC and/or polymer chains all can contribute to the superior properties of the composites. For this reason, fabrication approaches play an important role in determining the composite microstructure and ultimate mechanical behavior. This thesis focuses on customizing a new spinning approach for fabricating polymer/nC high-performance composite fibers. In particular, the nCs used in this work include stacked graphitic platelets (carbon nanochips (CNC)), carbon nanotubes (CNT), and layered carbon nano-spheres (CNS). Mechanical properties are characterized using both static tensile tests and dynamic mechanical analysis (DMA). Thermal properties are examined using differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA). Finally the microstructures of the materials are experimentally probed using wide-angle X-ray diffraction (WAXD) and small-angle X-ray (SAXS). Detailed exploration regarding the fabricated fiber microstructure is conducted to fundamentally understand the processing-microstructure-performance relationship in these polymer-based composite fiber systems.