The crystallization and melting behaviors were determined by
rheology using a Rheometric Mechanical Spectrometer (RMS-800)
and by differential scanning calorimetry (DSC) using a TA Instruments
Q1000 thermal analyzer, repectively. Rheological ‘‘cooling
curves’’ were made by cooling the temperature of the nanocomposite
melt at a rate of 40 C/min and recording the storage
modulus, G0 . A 25 mm cone and plate geometry was used with an
inert atmosphere. Samples were dried for 24 h at 120 C prior to
testing. The DSC was calibrated using sapphire and indium standards.
Test specimens of about 10 mg were cut and sealed in
hermetic aluminum pans. All tests were carried out under
a nitrogen atmosphere. Samples were heated from 40 C to 290 C,
equilibrated for 5 min and cooled back to 40 C, and then reheated
to 290 C. The heating and cooling rates were set at 20 C/min. The
degree of crystallinity was calculated under the assumption that
the heat of fusion is proportional to the crystalline content, as
shown in Eq. (1)