For the dynamic mechanical analysis (DMA), all the SMP samples,
with the same dimension of 10 mm 5 mm 0.9 mm, were
tested by a DMA tester (TA Instruments, Model Q800) using the
tensile mode. The samples were firstly heated to 95 C and stabilized
for 20 min to reach thermal equilibrium, and then a preload of
1 KPa and an initial strain with a magnitude of 0.1% were applied.
During the experiment, the strain was oscillated at a frequency of
1 Hz with a peak-to-peak amplitude of 0.1% while the temperature
was decreased from 95 C to 5 C at a rate of 1 C/min. The temperature
in the chamber was held at 5 C for 30 min and then
increased to 95 C at the same rate. This procedure was repeated
multiple times and the data from the last cooling stepwas reported.
Fig. 2 shows the experimental results of the DMA experiments. The
temperature corresponding to the peak of the tan d curvewas taken
to be the glass transition temperature Tg, and the storage modulus
of each sample was also plotted as a function of temperature.
As shown in Fig. 2, within the entire range of testing temperature,
the storage modulus of the SMP composites increases