专业英语翻译。高分子材料

提问者： hdyzjx     浏览次数：572    提问时间：2013/12/25 9:21:38

was fitted with rubber grips to ensure uniform stress
transfer from the grips to the samples in order to decrease
the chance of sample failure at the grips. Both sides of the
tensile test sample clamping areas were coated with a
0.5 mm layer of rigid epoxy for the same reason. There-
fore, only maximum tensile stress was evaluated, as sample
stiffness and elongation at break were not measurable using
this test method. Reference samples of pure 50-LCR-5k
and 73-LCR-9k polymer were also tested in the same
manner.
Dynamic mechanical thermal analysis was performed
using a Perkin Elmer Pyris DMTA in a nitrogen atmo-
sphere. A reference sample of pure 50-LCR-5k polymer
was also tested. The measurements were performed at 0.1,
1 and 10 Hz, over a temperature range of –100 to 300 C.
Results and discussion
Composite morphology
Using the production procedures illustrated in Fig. 3a, b
fully dense composites were obtained. A spatially uniform
distribution of the PZT particles has been obtained as
shown in the SEM micrograph of a fracture surface
(Fig. 4). Observations at higher magnification revealed a
very good adhesion between the matrix and the PZT par-
ticles. Such a good adhesion is typical for the reactive end-
group LCR polymer [12].
Dielectric and piezoelectric properties of the composite
materialDielectric properties of the composite material
The dielectric constant as a function of the PZT loading
fraction is shown in Fig. 5. In this figure the dependence as
predicted by the Yamada model is also plotted. The fit
equation was determined for composite samples with as
received PZT powder only. A relatively good fit was ob-
tained.
The values for the dielectric constants of the pure 50-
LCR-5k polymer and the 73-LCR-9k polymer were mea-
sured to be 3.26 and 3.64 at room temperature and 110 Hz.
The e
33
value of (poled) PZT material either in the as
received or in the calcinated state was estimated to be equalto that of sintered PZT of e
r
= 1,820. Although the XRD
analysis revealed the presence of multiple phases on both
sides of the MPB the dependence of the dielectric constant
on composition is fairly linear near the overall composition
[15] and hence the average value remains the same even
while sintering leads to a reduction of the local composi-
tion fluctuations.