Authors: I. Kong, S. Spoljaric, R.A. Shanks
Affilation: RMIT University, Australia
Pages: 211 - 214
Keywords: nano-magnetite, thermal stability, viscoelasticity, induction
The aim was to prepare composites of PU and magnetite-functionalized CNTs, using physical blending techniques in melt and solution. Objectives included functionalizing the CNT with magnetite (Fe3O4), preparing PU-CNT-Fe3O4 composites using solvent dispersion and melt mixing, and determining the influence of processing technique on the thermomechanical, thermal and magnetic properties of the composites. Characterization was performed using thermogravimetry, creep and recovery testing (Figure 3), modulated force thermomechanical analysis and magnetic induction (Figure 4). Filler distribution and concentration were found to be crucial factors that determine composite thermal stability. Tensile properties and glass transition temperature (Tg) increased with magnetite-CNT concentration in the PU, while creep deformation decreased. Composites prepared via melt mixing were stronger and less-elastic in behavior than those prepared using solvent dispersion. The four element and Kohlrausch–Williams–Watts (KWW) models were successfully utilized to describe creep and recovery behavior, respectively. Incorporation of magnetite-CNT caused the films become more solid-like, as indicated by the decrease in retardation time. Material properties were influenced by filler concentration and processing technique.