Characterization of Poly(Methyl Methacrylate) and Thermoplastic Polyurethane-Carbon Nanofiber Composites Produced by Chaotic Mixing
Year: 2007
Type: article
Abstract: The as-received CNF and CNFOX fibers were highly entangled and showed regions of amorphous carbon which acted as a deterrent to dispersion.The presence of higher content of oxygen-containing functional groups in CNFOX improved their dispersion in PMMA and TPU, but produced electrical percolation at much higher concentrations except in the case of TPU based on crystalline soft segment.Thermal stability and thermo-oxidative properties of the polymers were improved in the presence of carbon nanofibers.It was found that the aspect ratio of carbon nanofibers was preserved and that carbon nanofibers were aligned along the flow direction during chaotic mixing.This led to electrical percolation at much lower nanofiber content, compared to materials produced in a commercial internal mixer.It was also found that crystallinity and phase separation in TPU materials in a chaotic mixer was affected much less by the presence of carbon nanofibers, while TPU materials produced in the commercial mixer showed more phase mixing.Carbon nanofibers interacted with both soft and hard phases in TPU.Composites with CNFOX showed higher crystallinity which resulted in high stress recovery, high fixity, and recovery ratio.Both CNF and CNFOX improved the tensile properties of TPU when measured above the melting temperature of PCL.
Author: Guillermo Jiménez
Institution: University of Akron
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Award: G6671297155
OpenAlex ID: W258292582