Evaluation of the Degree of Exfoliation in Poly(epsilon-caprolactone) Nanocomposites Using by the Dynamic Mechanical Analysis
J.W. Chung, J-D Jeon and S-Y Kwak
Seoul National University, KR
nanocomposite, poly(epsilon-caprolactone), exfoliation, interfacial interaction
Nanocomposites composed of poly(epsilon-caprolactone) (PCL) and the organoclays which were layered silicate with the organic modifiers, i.e., nonpolar (OC25A) and polar (OC30B), were prepared by melt mixing. After mixing, we imposed additional heat to PCL/organoclay nanocomposites. Then, the effect of interfacial interaction between PCL and the organoclays was investigated using dynamic mechanical analysis. Nanocomposite with OC25A was named PCLOC25A, and that with OC30B was denoted PCLOC30B. WXRD results verified that both nanocomposites are completely exfoliated due to the additional heating. Then, logG''(w) versus logG'(w) plots for both nanocomposites are independent of temperature. These imply that both nanocomposites have no more structural change over the temperature range, because both nanocomposites already have been completely exfoliated by additional heat imposition. Besides, logG''(w) versus logG'(w) plots demonstrates that PCLOC30B is the most elastic. These results can be also confirmed by the master curves of the storage moduli and the complex shear viscosity of both nanocomposites formed by the time-temperature superposition applying only frequency shift factors. Activation energies of PCLOC30B calculated by WLF equation were exhibits higher activation energies than the others, too. These are due to formation of the polar interaction in PCLOC30B, it is concluded that more strong interfacial interaction improves the mechanical properties of nanocomposite.
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Nanotech 2005 Conference Program Abstract