Chemistry Reference
In-Depth Information
CF
3
n
O
CF
3
O
O
S
CF
3
O
O
S
N
H
O
S
O
O
(CH
2
)
6
S
S
n
H
N
n
All of the above polymers exhibit large absorption bands in the visible region of the spectra and the
norbornadiene moieties in these polymers isomerize very rapidly. In addition, the norbornadiene
moieties also exhibit efficient fatigue resistance [
185
].
Kawatsuki et al. [
186
] synthesized styrene polymers with pendant norbornadiene groups attached
via amide linkages:
n
R
O
O
N
H
where R is a methoxy or a ring-substituted aniline group attached through the nitrogen or at another
position. These pendant groups also undergo reversible conversions into quadricycline units in
polymer films when irradiated by ultraviolet light of two different wavelengths. The materials exhibit
high photosensitivity as well as a large red-shift in the absorption spectrum upon irradiation.
Sampei et al. [
187
] reported that polyaddition of 2,5-norbornadiene-2,3-dicarboxylic acid
diglycidyl ester to adipoyl chloride gave a polyester containing norbornadiene residues in the
polymer backbone and in the pendant groups. When a photochemical rearrangement of
norbornadiene residues took place in polymer films, the rate of the photochemical reactions in the
polymer backbones was higher than that in the side chains [
187
].
Kawashima et al. [
188
] reported preparation of donor-acceptor type norbornadiene carboxylic
acids compounds with carbamoyl groups, such as dipropylcarbamoyl, methylphenylcarbamoyl,
propylcarbamoyl, and phenyl-carbamoyl. Benzyl esters were also prepared. Addition of these groups
to polystyrenes formed polymers with pendant donor-acceptor type norbornadiene. Some were
formed with 100% substitution. It was found that the polymers containing phenylcarbamoyl groups
exhibit especially high photo-reactivity. In addition, the rate of the photochemical reaction in films of
these norbornadiene polymers increases efficiently by an addition of 4,4
0
-bis(diethyl-amino)benzo-
phenone photosensitizer. As a result, all the norbornadiene groups of the polymers isomerize to the
