M. Berrada et al., PHOTOINDUCED POLYMERIZATION OF BISIMIDES AS MODELS FOR NEW SOLUBLE SIDE-CHAIN-SUBSTITUTED NEGATIVE-TYPE PHOTOSENSITIVE POLYIMIDES, Chemistry of materials, 8(5), 1996, pp. 1022-1028
In this paper, we study the photoinduced polymerization of bisimide mo
dels for our new soluble side-chain-substituted negative-type photosen
sitive polyimides (PSPI) in order to better understand the polymerizat
ion behavior of the latter. These model compounds were cross-linked by
UV irradiation in the solid state and in N-methyl-2-pyrrolidinone (NM
P) solution. Variations in the molecular structure of the photosensiti
ve moieties were explored to change the photosensitivity of models and
of polymers. The kinetics of photopolymerization of these bisimide mo
dels was investigated by using infrared and UV techniques. The cinnama
te and furylacrylate derivatives were found mainly to photodimerize, w
hereas the two others, acrylate and methacrylate derivatives, photopol
ymerize. Reaction orders of 1.5 and 2.0 were verified in the case of m
odels but could not be determined for the polymers, due to the restric
tion of mobility of the photosensitive side groups on the polymer chai
ns (solid-state irradiation) and also because the cross-linked polymer
was no longer soluble in NMP and precipitated as it was formed.