Syntheses of TLCPs and Their Nanocomposites
Preparation of Poly(2-ethoxyhydroquinone-2-bromoterephthaloyl)
(EHBT) Nanocomposites
The compound 2-ethoxyhydroquinone was synthesized via a multistep route (Lenz
et al. 1991), and 2-bromoterephthalic acid was purchased from Aldrich Chemicals.
Poly(2-ethoxyhydroquinone-2-bromoterephthaloyl) (EHBT) was prepared by direct
polycondensation of equivalent weights of the appropriate 2-ethoxyhydroquinone and
2-bromoterephthalic acid in the presence of thionyl chloride (SOCl 2 ) and pyridine. The
detailed procedure was also described earlier by us (Chang et al. 1994). The ethoxy
substituent and -Br on the TLCP not only lower the melting point but also improve the
suitability for some applications. The polymer formed was thoroughly washed with
methanol, with dilute HCl, and then with water before drying at 60
C in a vacuum
oven. The chemical structure of EHBT is shown in Scheme 1. Figure 1 shows the
thread nematic textures of pure EHBT at 202
C and 215
C.
The inherent viscosity of the EHBT was 0.64 dL/g, which was measured at 30
C
in solutions with a concentration of 0.2 g/dL in a phenol/1,1,2,2-tetrachloroethane
(TCE) = 50/50 (v/v) mixture. The solution viscosity values (see Table 1) ranged
from 0.64 to 0.78. Considering that these viscosity values were obtained from pure
EHBT in EHBT hybrids from which the clay content had been removed; these
numbers can be regarded as constant.
For simplicity, the hybrids are referred to in this paper as 0 wt% organoclay/
TLCP, 3 wt% organoclay/TLCP, and so on, in which 3 wt% organoclay and TLCP
are the organoclay and polymer components used to prepare the hybrids, respectively, and the number denotes the organoclay weight percent in the hybrid.
Because the synthetic procedures for C25A/EHBT nanocomposites with different wt
% organoclay are very similar, only a representative example for the preparation of
O
C
O
O
n
O
n
N
n
CO
Br
O
C
O
CO
CH 3 CH 2 O
OC 6 H 13
H 13 C 6 O
HC
EHBT
CH 3
OBDT
CH=N
PAM
Scheme 1 Chemical
structures of EHBT, OBDT,
and PAM TLCPs
582
T. Y. Ha et al.
Preparation of Poly(2-ethoxyhydroquinone-2-bromoterephthaloyl)
(EHBT) Nanocomposites
The compound 2-ethoxyhydroquinone was synthesized via a multistep route (Lenz
et al. 1991), and 2-bromoterephthalic acid was purchased from Aldrich Chemicals.
Poly(2-ethoxyhydroquinone-2-bromoterephthaloyl) (EHBT) was prepared by direct
polycondensation of equivalent weights of the appropriate 2-ethoxyhydroquinone and
2-bromoterephthalic acid in the presence of thionyl chloride (SOCl 2 ) and pyridine. The
detailed procedure was also described earlier by us (Chang et al. 1994). The ethoxy
substituent and -Br on the TLCP not only lower the melting point but also improve the
suitability for some applications. The polymer formed was thoroughly washed with
methanol, with dilute HCl, and then with water before drying at 60
C in a vacuum
oven. The chemical structure of EHBT is shown in Scheme 1. Figure 1 shows the
thread nematic textures of pure EHBT at 202
C and 215
C.
The inherent viscosity of the EHBT was 0.64 dL/g, which was measured at 30
C
in solutions with a concentration of 0.2 g/dL in a phenol/1,1,2,2-tetrachloroethane
(TCE) = 50/50 (v/v) mixture. The solution viscosity values (see Table 1) ranged
from 0.64 to 0.78. Considering that these viscosity values were obtained from pure
EHBT in EHBT hybrids from which the clay content had been removed; these
numbers can be regarded as constant.
For simplicity, the hybrids are referred to in this paper as 0 wt% organoclay/
TLCP, 3 wt% organoclay/TLCP, and so on, in which 3 wt% organoclay and TLCP
are the organoclay and polymer components used to prepare the hybrids, respectively, and the number denotes the organoclay weight percent in the hybrid.
Because the synthetic procedures for C25A/EHBT nanocomposites with different wt
% organoclay are very similar, only a representative example for the preparation of
O
C
O
O
n
O
n
N
n
CO
Br
O
C
O
CO
CH 3 CH 2 O
OC 6 H 13
H 13 C 6 O
HC
EHBT
CH 3
OBDT
CH=N
PAM
Scheme 1 Chemical
structures of EHBT, OBDT,
and PAM TLCPs
582
T. Y. Ha et al.