Alignment of carbon nanotubes and reinforcing effects in nylon-6 polymer composite fibers

Abstract

Alignment of pristine carbon nanotubes (P-CNTs) and fluorinated carbon nanotubes (F-CNTs) in nylon-6 polymer composite fibers (PCFs) has been achieved using a single-screw extrusion method. CNTs have been used as filler reinforcements to enhance the mechanical and thermal properties of nylon-6 composite fibers. The composites were fabricated by dry mixing nylon-6 polymer powder with the CNTs as the first step, then followed by the melt extrusion process of fiber materials in a single-screw extruder. The extruded fibers were stretched to their maxima and stabilized using a godet set-up. Finally, fibers were wound on a Wayne filament winder machine and tested for their tensile and thermal properties. The tests have shown a remarkable change in mechanical and thermal properties of nylon-6 polymer fibers with the addition of 0.5 wt% F-CNTs and 1.0 wt% of P-CNTs. To draw a comparison between the improvements achieved, the same process has been repeated with neat nylon-6 polymer. As a result, tensile strength has been increased by 230% for PCFs made with 0.5% F-CNTs and 1% P-CNTs as additives. These fibers have been further characterized by DSC, Raman spectroscopy and SEM which confirm the alignment of CNTs and interfacial bonding to nylon-6 polymer matrix.

Multiscale Polymer Composites: A Review of the Interlaminar Fracture Toughness Improvement

“…Previous studies reported improved mechanical performance of conventional composites with the addition of nano fillers [119][120][121][122][123][124]. Researchers also verified that the toughness of the composite improves because of nano fillers [125,126].…”

“…Moreover, the benefits of increasing delamination resistance in fiber reinforced composites have been proven using multiscale reinforcement, using fibers and CNTs together on the resin system or on the surface of the fibers [5,[119][120][121][122][123][124]. The ILFT of the multiscale composite is of further interest.…”

Carbon Fibers and Their Composites

“…Zhang et al found that after the CNT yarn was pulled through droplets of ethanol, the several centimeterwide yarn shrank into a tight fiber, typically 20-30 µm in diameter, and the strength of the CNT yarn dramatically improved. The CNT alignment was found to be crucial for fiber properties [93,94] and could be measured by Raman and X-ray diffraction (XRD) [95,96]. Zheng et al [97] observed a strong correlation between the array morphologies (the straightness of CNTs) and the fiber properties and well-aligned arrays yielded high performance, while wavy arrays led to poor performance.…”

Preparation and characterization of polyamide 6 nanocomposites using MWCNTs based on bimetallic Co-Mo/MgO catalyst

“…Several researches have also been reported considering different aspects of thermal, mechanical, electrical and rheological properties of nanocomposites which have used in situ polymerization, solution casting, melt spinning and melt compounding methods [3,4,[6][7][8][9]. Melt mixing of CNTs and thermoplastic matrices by single screw [10,11] or twin screw extruder [6,[12][13][14] is the most economical and desirable approach in comparison with other methods because, for fabricating these composites no additional equipment is needed. This process can be performed with conventional plastic machines, i.e.…”

“…However, in some cases there would be no any other method to obtain a desired product. Rangari et al [10] reported that the tensile strength of PA6 fibre nanocomposites prepared by a single screw extruder, enhanced by 230% which contained only 1 wt% unmodified CNTs, while De Zhang et al [6] indicted that tensile strength improved by about 124% with the same CNTs loading using twin -screw mixer. Phang et al [14] have studied the effect of CNTs on crystallinity of the polymer matrix prepared via melt compounding.…”