|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Nanocomposites V: Structure-Property Relationships in Nanostructured Materials
||Structure Property Relationship in Polyimide Nanocomposite for High-temperature Applications
||Colin Rowbottom, Jonathan Spowart, Hassan Mahfuz
|On-Site Speaker (Planned)
MVK-14 M Freeform® is a high temperature polyimide used in both autoclave processing and compression molding, having no mutagenic or carcinogenic components. This paper investigates the effects of reinforcing this resin system with Multi-Wall Carbon Nano-Tubes (MWCNTs) and Graphene Nano-Platelets (GNPs). The idea is to create a network (bridge) of two filler materials with the matrix and examine the structure-property relationships. Both nanofillers were functionalized with a carboxyl group (-COOH). Neat MVK-14 M Freeform® was used as a control and both MWCNTs and GNPs were also added individually into the matrix. Hybridization of MWCNT/GNP was carried out through a rigorous sonochemical process and its effects were studied via thermal, mechanical, FTIR, and SEM characterizations. In addition a non-ionic surfactant (Triton X-100®) was used to improve dispersion via steric hindrance. Initially the MWCNTs and GNPs were exfoliated in acetone via sonication. After initial dispersion, the surfactant was added into the solution to further disperse the filler materials. Then the admixture was dried for 24 hours in a vacuum oven to remove the solvent. Once dried, the reinforcements were further dispersed into the resin through additional sonication. After dispersion, first and second stage imidizations were completed using a baking oven and a compression molding press to produce 2” 2” samples. A comprehensive characterization schedule was then followed. Overall, it was observed that the dual inclusion strategy was better than the single inclusion of either MWCNT or GNP. Hybridization changed the sub-Tg (b) transition but there was no discernible shift in the glass transition (a) temperature. There was a significant change in the thermal degradation behavior as TGA curves showed evidence of multi-stage decomposition. Such multi-stage decomposition was attributed to the removal of surfactant from GNP surfaces resulting in higher weight loss at 8000C. SEM micrographs showed that GNP/MWCNT reinforcements can work as crack arresters during the fracture process. It was also noticed that without complete exfoliation, GNP dispersion is relatively poor. Nano-indentation tests suggested that dual inclusion of GNP and MWCNT increases the contact modulus by 30% and enhances the creep resistance.
||Planned: Supplemental Proceedings volume