Solidlike transition of melt-intercalated biodegradable polymer/clay nanocomposites

Synthetic biodegradable aliphatic polyester (BAP) intercalated into organo-clay was prepared by melt compounding, and its solidlike characteristics were investigated via several rheological test modes: steady shear rotation, oscillation, and creep testing. Structural investigations with X-ray diffraction and transmission electron spectroscopy were also performed for a better understanding of the characteristic rheological behaviors. The creep, recovery, and stress modulus exhibited a solidlike transition of BAP/clay nanocomposites that depended on the clay content. An increase in the zero shear rate viscosity and a shifting of the crossover point (storage modulus vs loss modulus) to a lower frequency were also observed with increasing clay contents. (C) 2003 Wiley Periodicals, Inc.