PTFE PhD Defense– An-Ting Chien
Dr. Satish Kumar, MSE (advisor)
Dr. Anselm Griffin, MSE
Dr. Donggang Yao, MSE
Dr. Chuck Zhang, ISyE
Dr. Hangi Chae, MSE
Various nano-fillers can introduce specific functions into polymers and expand their application areas. Myriad properties, such as mechanical, electrical, thermal, or magnetic properties can be combined with original polymer characteristics, including flexibility light weight, and ease of use. These composites can be used to produce multi-functional fibers as the next generation of textiles or fabrics. This research adopts polyacrylonitrile (PAN) as the matrix polymer with different nano-fillers, such as carbon nanotubes (CNT), iron oxide nanoparticles (Fe3O4), and graphene oxide nanoribbons (GONR). Gel-spinning technology is used to fabricate PAN-based composite fibers as single- or bi-component fibers. These fibers are characterized for their structure, morphology, and mechanical properties, as well as for their electrical, thermal, and magnetic properties. Bi-component fibers with a PAN sheath and a PAN/CNT core as well as a PAN/CNT sheath and a PAN core can exhibit good mechanical properties with CNT concentration as high as 20 wt% CNT in the PAN/CNT component. Such bi-component fibers can be used for wearable devices to provide electrical and thermal conductivities. Response of PAN/CNT composite fibers to the surrounding temperature (annealing process) and external force has also been investigated. Joule heating effect, which occurs when external current is applied on the PAN/CNT fibers, has also been studied. The results show that PAN/CNT composite fibers can be used as active heating fibers, and the electric current can increase the temperature of the PAN/CNT fibers high enough to stabilize and carbonize PAN. Single-component and bi-component composite fibers with well-dispersed magnetic Fe3O4 nanoparticles have been processed. These novel magnetic fibers with high strength and superparamagnetic properties at room temperature can be used for actuators, inductors, EMI shielding, or microwave absorption. In the final place of this project, GONR reinforced PAN-based composite fibers have been processed. Structure, processing, and properties of the PAN/GONR precursor and their stablized and carbonized products have been studied.