Thermal and rheological properties of highly concentrated PET composites with ferrite nanoparticles

• DOI: 10.1016/j.compscitech.2006.09.018
• Publication Date: 2006-11-22T10:22:48Z
• Authors: D CHAE; B KIM
• Keywords: Thermal Stability; Shear thinning

Abstract Ferrite nanoparticles were introduced into poly(ethylene terephthalate) (PET) in a melt state at 270 °C upto 20 wt%, and the thermal and rheological properties of the nanocomposites were investigated. The introduction of ferrite nanoparticles increased a little the crystallization temperature ( T c ) of PET by ca. 3 °C, while it had little effect on the melting temperature ( T m ). In addition, it increased both heat of crystallization (Δ H c ) and heat of fusion (Δ H m ) with ferrite content. PET nanocomposites with ferrite 5 wt% and above exhibited an increased thermal stability and a two-stage degradation. The dynamic viscosity of PET nanocomposites was increased with ferrite content. However, ferrite loading of 5 wt% and above produced a high degree of shear thinning leading to even lower viscosity in a high frequency range than that of pure PET. The nanocomposites gave a non-zero positive value of yield stress, which was notably increased particularly from 5 wt% loading. In the Cole–Cole plot, at contents 1 wt% and above, ferrite nanoparticles caused the deviation from the master curve and a reduced slope. In addition, the relaxation time was increased with ferrite content and an increasing degree was more notable at a lower frequency.