As part of our continuing studies is concerned with the free-radical crosslinking polymerization of multivinyl compounds, this article deals with the inhomogeneity of network structure accompanied by the radical accumulation which can be detected by electron spin resonance (ESR) method, in the radical polymerization of multiallyl compounds. Pendant allyl radicals were detected in the bulk polymerizations of triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), diallyl phthalate (DAP), diallyl isophthalate (DAI), diallyl terephthalate (DAT), and triallyl trimellitate (TAT). The pendant allyl radical easily reacted with oxygen, while no reaction was observed with 4-hydroxy-2, 2, 6, 6-tetramethylpiperidine-1 -oxyl (TEMPOL) as a bulky molecule. This kind of steric effect is ascribed to the inhomogeneity of network structure; thus the pendant allyl radicals belong to the densely crosslinked part. Conversion dependence of the pendant allyl radical accumulation was different for each polymerization; this reflects the difference of the network formation processes, especially including the occurrence of intramolecular crosslinking.

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Much attention has been paid to new development of photo-functional network polymers. This review article introduces synthesis and some properties of new photo-curable polymers, oligomers, and monomers. Thermally stable new polyimides with pendant epoxide or vinyl ether moieties have been synthesized. Photo-curable calixarenes containing (meth) acrylate groups, which are new (meth) acrylate monomer having excellent thermal stability similar to polyimides, have been synthesized by the reaction of p-methyl calix [4] arene with certain (meth) acrylate derivatives. Some poly-functional vinyl ether monomers and polymers have also been prepared by the addition reaction of glycidyl vinyl ether with poly-functional acyl chlorides, by the isomerization of the corresponding allyl ethers and so on. Furthermore, it was reported that certain photo-crosslinked functional polymers such as liquid crystalline polymers and NLO polymers containing cinnamoyl groups have ordinarily better functionality than the corresponding linear polymers. Soluble or insoluble polymers containing norbornadiene moieties in the main chain or the side chain, which were used for photo-energy exchange polymers, have been synthesized and studied their photochemical property and storage property of the thermal energy.

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Photopolymers have been developed as a material for the fine-patterning technology (lithography) such as print making facilitating the progress in the field of microelectronics.As a recent technical innovation, it is noticed to introduce the development of CTP (Computer To Plate) equipment, by which the direct plate making can be carried out without using the films and the press plate.This process needs a highly photosensitive polymer of responding to a long wave length region.Expectation will grow in the future progress on the material and the light-exposure device.

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Recent developments of photoacid and photobase generators and their use in the photocrosslinking of polymers described.On the photoacid generators, the basic concepts and their recent practical use in UV curing and photoresists are discussed, especially, laying stress on the surface imaging photoresists using polymers with pendant iminosulfonate groups. On the photobase generators which are recently developed, there are introduced their future applications in photocrosslinking and the feature of oxime esters as photobase generators.

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