distances for MMT; thus, it is clear that the XRD data shift to smaller angles for the
modified clay. A larger interlayer spacing should generally be advantageous in
intercalation of polymer chains. It should also lead to easier dissociation of the
clay and thus result in hybrids with better clay dispersion (Lagaly 1999).
Small peaks at d = 14.30 Å (2θ = 6.18
), 11.92 Å (2θ = 7.42
), and 9.74 Å
(2θ = 9.08
) appeared in the XRD results for pure OBDT. Similar XRD peaks
appeared for the OBDT hybrid with 1 wt% organoclay content. The intensity of the
XRD peak at d = 14.63 Å (2θ = 6.04
), however, increased as the clay loading was
increased from 3 to 7 wt%, suggesting that dispersion is more effective at lower clay
loadings than at higher clay loadings. Higher clay loadings are expected to result in
0
5
1 0
2θ (degree)
15
6
4
2
0 (pure EHBT)
d=18.84 Å
Intensity
d=15.67 Å
C25A
C25A in EHBT (wt%)
Fig. 3 XRD patterns of
C25A and EHBT hybrids with
various organoclay contents
d=21.35 Å
Intensity
d=11.98 Å
2θ (degree)
d=14.63 Å
d=14.30 Å d=11.92 Å d=9.74 Å
Na + -MMT
C18-MMT
C18-MMT in OBDT (wt%)
2
4
6
8
1 0
12
7
5
3
1
0 (pure OBDT)
Fig. 4 XRD patterns of Na
+ -MMT, C18-MMT, and OBDT hybrids with various organoclay
contents
21 Characterizations of Nanocomposites of Liquid Crystalline Polymers
589