Interfacial Crystallization in Gel-Spun Poly(vinyl alcohol)/Single-Wall Carbon Nanotube Composite Fibers

• Published in: Macromolecular chemistry and physics Vol. 210; no. 21; pp. 1799 - 1808
• Main Authors: Minus, Marilyn L., Chae, Han Gi, Kumar, Satish
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 06.11.2009; WILEY‐VCH Verlag; Wiley
• Subjects: Alcohols; Applied sciences; Composites; Crystal growth; Exact sciences and technology; Fibers; Forms of application and semi-finished materials; interfaces; Modulus of elasticity; nanocomposites; nucleation; poly(vinyl alcohol); Polymer industry, paints, wood; Polyvinyl alcohols; Reinforcement; Single wall carbon nanotubes; SWNT; Technology of polymers; Tensile strength; interfaces; poly(vinyl alcohol); Synthetic fiber; Mechanical properties; Carbon nanotubes; Tensile property; Crystallinity; Experimental study; Property processing relationship; SWNT; nanocomposites; Gel spinning; Structure processing relationship; Polyvinylalcohol; nucleation; Singlewalled nanotube; Hot drawing; Oriented polymer; Morphology; Nanocomposite
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.200900223

PVA and PVA/SWNT fibers (PVA = poly(vinyl alcohol), SWNT = single‐walled nanotubes) were processed by gel spinning. At 1 wt.‐% SWNT loading, tensile strength increased from 1.6 GPa for the control PVA to 2.6 GPa for PVA/SWNT composite. Analysis of this data suggests stress of up to ≈116 GPa on the SWNT in the composite fiber. This confirms excellent reinforcement and load transfer of SWNT in the PVA matrix. Tensile modulus of the fiber is also increased from 47 GPa for the control to 70 GPa for the composite. Interfacial studies using high‐resolution transmission electron microscopy reveal extended‐chain crystal growth of PVA at the PVA–SWNT interface. High SWNT alignment in the fiber is revealed, where the polarized Raman G‐band ratio $\left( {{{I_{0^ \circ }^{{\rm VV}} } \mathord{\left/ {\vphantom {{I_{0^ \circ }^{{\rm VV}} } {I_{90^ \circ }^{{\rm VV}} }}} \right. \kern-\nulldelimiterspace} {I_{90^ \circ }^{{\rm VV}} }}} \right)$ is as high as 106. Composite fiber shrinkage in water is reduced by ∼70% when compared to the control PVA fibers. Study of polymer crystallization in the vicinity of SWNT (interphase) helps in understanding SWNT's influence on polymer morphology in bulk fibers. At 1wt.‐% SWNT loading in PVA, fiber (see figure) tensile strength and modulus is 2.6 and 71GPa, respectively. The effective stress on the SWNT in the composite fiber was calculated to be 116GPa, and this suggests excellent reinforcement efficiency in the PVA matrix.