Chemistry Reference
In-Depth Information
The preparation of such polymeric materials can be illustrated as follows [
241
]:
+
HO
OH
X
Y
X
N N
R
O
O
Y
n
N N
R
where R
carbonyl, sulfone, or a diketone aryl group. The above shown
medium and high molecular weight polymers exhibit good solubility in solvents like dimethyl
acetamide and good thermal stability. The same is true of the other poly(arylene ether)s mentioned
above. As a result, these high-performance thermoplastics have the potential of being useful in low
cost composite fabrications.
One paper [
242
] describes preparation of poly(imidoaryl ether ketone)s and poly(imidoaryl ether
sulfone)s that exhibit particularly good heat stability. The synthesis can be illustrated as follows:
¼
H, Ph; X
¼
Cl, F; Y
¼
K
2
CO
3
solvent
160-220
o
C
+
F
HO
OH
X
F
OO
R
O
X
n
OO
R
where: R
SO
2
; CO; Isophthaloyl; Based on thermogravimetric
analyses, the phenyl substituted polymers lose only 10% of their weight in air and in nitrogen at
550
C. In addition, the polymers have high glass transition temperatures and remain soluble in
common solvents, like chloroform and methylene chloride. These are high molecular weights
polymers that can be cast from solution to give tough, flexible films [
242
].
¼
CH
3
;CH
3
(CH
2
)
11
; Phenyl; X
¼
7.18 Dendrimers and Polyrotaxanes
One of the fascinating things about polymer chemistry is the ability of the chemists to develop new
and interesting molecular structures. This can result in formation of materials with unique properties.
Among such materials are dendrimers and polyrotaxanes.
