The morphological observations were executed using a scanning
electron microscope (SEM) (TM3000, Hitachi High-Technologies
Co., Ltd.). In order to be observed more clearly and have better
conductivity, the surfaces of the specimens were sputter-coated
with gold prior to their observation.
Dynamic mechanical analysiswas performed with a DMAþ1000
dynamic measurement system (Metravib, France) using a constant
frequency of 10 Hz the specimens were heated at a rate of
5 C min1 from 80 to 0 C.