Amorphous-to-Crystalline Phase Transformation of Carbon Nanotube Reinforced Polyetheretherketone Composites via Resistive Heating
presentationposted on 07.08.2014, 00:00 by Alicia Martin
Polyetheretherketone (PEEK) is widely-used because it has high mechanical strength and stiffness for a polymer and is used as a thermoplastic matrix for composite materials. Multi-Walled Carbon Nano Tubes (MWCNT) offer excellent reinforcement qualities to PEEK matrices due to their dispersion characteristics, outstanding mechanical properties, and electrical conductivity. The overarching goal of this research direction was to create a PEEK-MWCNT composite that exhibited shape-memory behavior. Preliminary emphasis was placed on investigating the role of the structure during heating. The experimental approach was to resistively heat the PEEK-MWCNT composite to induce the amorphous-to-crystalline transition which is typically associated with shape-memory behavior. The methodology consisted of developing a repeatable method to manufacture amorphous PEEK composites using conventional high-pressure powder sintering techniques. Dynamic mechanical analysis, stress-strain tests, fracture analysis, and resistive heating tests were performed to characterize the composite properties. A focus was placed on understanding the underlying microstructure and its influence on the bulk material behavior. Preliminary manufacturing and characterization trials of PEEK-MWCNT composites were performed. Samples were thermomechanically tested and resistively heated. The composite showed an increase in strength and stiffness over pure PEEK and increasing temperature was achieved by an applied voltage.