| 초록 |
Large Amplitude Oscillatory Shear (LAOS) is a test method for the characterization of complex fluids. Among several LAOSanalysis methods, the Fourier Transform (FT)-Rheology is sensitive method.I proposed a new nonlinear coefficient Q established from FT-Rheolgyunder LAOS. The parameter Qis defined as Q ≡ I3/1/02where I3/1is the normalized 3rd harmonic contribution. Asymptotic value zero-strain nonlinearity, Q0, the inherent non-linearity for vanishing strains can be defined. Using this concept entangled linear monodisperse polymer and comb polymer melts were investigated towards these nonlinear parameters (Q and Q0). In this study, I also applied Q and Q0 to study polymer composite systems. I have investigated nonlinear and linear viscoelastic response under dynamic oscillatory shear flow for polymer composite system with various shapes of nanocomposite, e.g. PCL/MWNT (multiwall carbon nanotube), PCL/ OMMT (orgnomodified montmorillonite) and PCL/PCC (precipitated carcium carbonate). For better comparison of polymer composite system, I propose new parameter as the Nonlinear-Linear viscoelastic Ratio (NLR) as a function of composite concentration.It can be inferred that NLR can be used as a quantitative measure to assess the dispersion quality of polymer nanocomposites. |
