Session: K7-01: THERMOPHYSICAL PROPERTIES I

Paper Number: 131423

131423 - Enhanced Thermal Conductivity of Expanded Graphite/polyetherimide Composites Prepared by Auxiliary Intercalating Agents 

Abstract: 

Polymer composites are emergent thermal management materials in electronic industries. In this study, the impact of auxiliary intercalating agents on the thermal conductivity of expanded graphite (EG) polymer composites was investigated. The intercalation of graphite was perfumed in the presence of hydrogen peroxide (H₂O₂) and sodium chlorate (NaClO₃) as auxiliary intercalating agents, and thermal expansion techniques were employed to prepare the EG filler. An extraordinary enhancement (ca. 3030%) in the thermal conductivity of polyetherimide/graphene nanocomposites (k = 7.2 Wm^-1K^-1) was achieved by incorporating only 7.5 wt% EG filler to the polymer matrix, compared to pure polyetherimide (k ~ 0.23 Wm^-1K^-1). The interconnected graphene network, facilitated by EG, created a percolative environment, fostering highly efficient thermal transport in the composite. A combination of oxidizing agents, H₂O₂ and NaClO₃ coupled with H₂SO₄, primarily induced the intercalation of graphene sheets at the edges, followed by the sequential intercalation of the basal plane structure.  Comprehensive characterization of these composites with Raman spectroscopy (Raman), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and field-emission scanning electron microscopy (FE-ESEM) revealed the combined impacts of H₂O₂ and NaClO₃ induced intercalation on the structural and chemical composition of EG. Of particular note, the results revealed this EG filler created a three-dimensional (3D) porous structure within the polymer composite, ultimately influencing the thermal conductivity. This study sheds light on the role of intercalating agents in expanded graphite/polymer composites multi-scale structures and introduces a novel approach for achieving ultra-high thermal conductivity values in polymers.

Presenting Author: Keisha Walters University of Arkansas

Presenting Author Biography: Dr. Keisha Bishop Walters is a Professor and the Department Head of the Ralph E. Martin Department of Chemical Engineering at the University of Arkansas. Her research is focused on advanced polymers, nano-scale materials engineering, and transport modeling. Dr. Walters is committed to effective undergraduate and graduate teaching, STEM outreach to K-12 and community college students, and professional development curricula centered around career readiness and success.

Authors:

Fatema Tarannum University of Arkansas
Keisha Walters University of Arkansas
Jivtesh Garg University of Oklahoma