Investigating the phase morphology and distribution of different nanofillers within the reaction induced phase separated structure of an epoxy blend

Abstract

Nanoparticles have been successfully incorporated into epoxy resin to enhance the multifunctional properties of the resulting nanocomposites. Additionally, for achieving next-level performance, selectively locating nanofillers in specific areas by tailoring the mixture of two immiscible polymers has been widely investigated. However, forming a phase-separated structure from entirely miscible molecules is rarely reported and the related mechanisms to govern the formation of assemblies from molecules have not been fully resolved.
Herein is demonstrated a novel method to fabricate self-assembling, bi continuous, biphasic structures, with localised domains made up of amine-functionalized graphene nanoplatelets (A-GNPs) by tailoring the compositions in a multi-component epoxy blend. As a consequence, a dielectric polymer composite with high thermal conductivity and mechanical properties was successfully fabricated. This simple process for fabricating well-structured nanocomposite with nanoparticles being integrated into assemblies of the nano-micro domain and its related collective properties offers a promising new approach to fabricating nanocomposite film, which has the potential applications in new energy systems, such as microelectronic packaging and thermal management. The newly emerging techniques Nano-IR and O-PTIR were employed to access the chemical mapping of self-constructed bi-continuous phase-separated microstructure, which clearly reveals that
the dissimilarity of chemical distribution in different regions was the main reason for the phase separation. This chemical analysis proposed here affords practical solutions of Nano-IR and O-PTIR for investigating the phase behaviour of multi-component systems within submicron resolution. This series of in-depth studies filled the blank of direct chemical analysis for investigating the mechanism
of the phase behaviour nanofiller-reinforced thermoset blends, presenting as consolidated support
complementary to the research reported previously, which heavily relied on imaging and thermal analysis techniques.
Finally, combining results from diverse experimental characterization with theoretical studies and molecular dynamics (MD) simulations, we reveal that the change of the miscibility discrepancy between the nanofillers and the different chemical components during the polymerisation plays a crucial role in determining the microstructures and the corresponding properties. This study provides a simple yet sophisticated engineering model and the mechanism for fabricating nanocomposite film with desired phase morphologies and properties.

Date of Award	21 Mar 2023
Original language	English
Awarding Institution	University of Bristol
Sponsors	Chinese Scholarship Council
Supervisor	Ian Hamerton (Supervisor) & Carwyn Ward (Supervisor)