Chitosan-Ammonium dichromate polymer(CT-AD) was prepared and irradiated by UV light with a high pressure mercury lamp. It was found that CT-AD polymer, having crosslinking structure, undergoes a photodecomposition reaction. Owing to the photodecomposition reaction the solubility differential of the polymer is readily obtained. After development the soluble parts of the polymer were washed out and positive image was obtained. Characteristic curves of CT-AD polymer were made and showed in Fig. 1. These curves indicate that the more the incident energy of UV light was irradiated on the polymer, the more the soluble parts of the polymer were obtained. The influence of the content of AD in the film on the photosensitivity of the film was displayed in Fig. 2. Soluble parts of CT-AD polymer which were obtained after UV exposure decrease when AD content in the film increases. Thickness of the film is an important factor which influences the development process. In oder to investigate the mechanism of the photodecomposition reaction, UV irradiation of CT-AD polymer in HAc water solution was carried out for different periods of time and after irradiation the UV spectra (Fig.4) and the electric conducvivity (Fig.5) of the solutions were measured. The ammonium dichromate solution was also irradiated by UV light at the same time, it exhibits the absorption at 250, 350, 400nm, when the pH<7 (Fig.3). The UV spectrum of the CT-AD polymer in olution indicates that the absorption peaks shift from 266.2 to 250, 360.2 to 350nm, which are in accord with the absorption peaks of UV spectrum of the AD solution at pH<7. The enhanced electric conductivity proves the transition of dichromate ions to the solution. The mechanism of photodecomposition of CT-AD polymer is dependent initially on the transition of chromium from a high to low state of oxidation, followed by a decomposition of CT-AD polymer.

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A series of new polymers were obtained by linear addition polymerization of diepoxy compounds with piperazine. Most of the polymers were soluble or developable in dilute acids because of the molecules containing teritiary amino groups. One of the above polymers was prepared from N, N-diepoxypropylaniline with piperazine. Some photosensitive systems can be formed from this polymer with polyhalides and can be photocolorized and photocured simultaneously upon irradiating with near UV (300-400nm). The minimum quantity of exposure energy required for photocuring (E_cur) is 78mJ/cm². But some properties of this polymer are inadequate in practice.
This paper emphasised another new type three-component polymers which were prepared by bisphenol A epoxycompounds and N, N-diepoxypropylaniline with piperazine. These polymers possessed some improved properties, such as photosensitivity, adhesion, alkali resistance and lipophilic nature. E_cur of these polymers --CBr₄ photosensitive systems can be as low as 110mJ/cm². When 50% CBr₄ and 5% 2, 4-diethylthioxanthone are added to them E_cur can decrease to 99mJ/cm². A good effect can be obtained for increasing photosensitivity if 5% 2, 6-bis-(azidobenzal)- 4-methycyclohexanone and 50% CBr₄ are added to them. E_cur of these systems can approach 10mJ/cm². The image of cured film on aluminium can be etched by dilute sodium hydroxide solution. The initial research on the mechanism of photo- curing and photocoloration obtained significant results.

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Photoinitiation systems were investigated to obtain visible light sensitive photopolymerizable composition with high sensitivity to be applied to the argon laser scanning imaging systems. Each of thioxanthene dye (Dye-1), coumarin dye (Dye-2) and merocyanine dye (Dye-3) was combined with various amounts of diphenyl iodonium cloride (DPI) and/or N-phenylglycine (N-PhG) as the radical precursors to form the photoinitiation systems. A layer of the mixture of a photoinitiation system, polyfunctional acrylic monomer and acrylic polymer was applied on an aluminium plate to prepare a test plate for evaluation. In orders to eliminate inhibition of polymerization by oxygen, a poly- (vinyl alcohol) layer was applied on the top of the test plate.
The sensitivity of the test plates containing initiation systems of dye/DPI/N-PhG were approximately five times as high as those containing dye/DPI or dye/N-PhG in every kind of dye. The same tendency was observed in image formation with an argon laser scanning imaging system using Dye-1-containing test plates. The minimum energy required to form gel of the Dye-1, Dye-2 and Dye- 3-containing system were 0.3, 0.2 and 1.7mJ/cm² respectively.

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Four kinds of amphiphilic aromatic compounds which one might expect to undergo efficient [2+2] or [4+4] photocycloadditions have been prepared for the investigation on photochemical reactions in Langmuir-Blodgett films. The properties of monolayers were very sensitive to molecular structure. The strong interaction of chromophores in LB films showed remarkable shift in electronic spectra.

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Photoreactive multilayer films were prepared using long-chain alkyl diesters of p-phenylenediacrylic acid (p-PDA) such as p-PDA di-n-dodecyl ester and p-PDA di-n-tetradecyl ester. In spite of the absence of hydrophilic groups in these molecules, they formed stable monolayers on the water surface when mixed with arachidic acid. Surface pressure-area isotherms for mixed monolayers from these esters and arachidic acid showed the presence of a condensed phase and these monolayers could be transferred onto a substrate with Y-type deposition. The UV spectra of mixed multilayer films showed blue shift of absorption peak compared with that in solution. This indicates side by side molecular arrangement in these films. The linear relationship between absorbance and the number of layers supports the successful formation of multilayer films. Photoreaction of multilayer films occurred by cycloaddition of double bonds at initial stage and then a vinyl-type polymerization yielding polymers via oligomers. Irradiation of a m nolayer formed at water/air interface caused a monolayer to shrink resulting the formation of oligomers. In the crystalline state, photopolymerization proceeded topochemically forming cyclobutane rings in the main chain of polymers. The photochemical behaviour in these differentstates was discussed with reference to the molecular arrangement.

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The development of modern scientific and engineering technology reqires recording materials that are capable of instantaneous recording and displaying. Polymer can be used as photosensitive materials. for this purpose. Two such recording materials i.e the acid sensitive colour changing recording material and PVK film have be studied and developed in our laboratory. It was found they are sensitive to the deep UV light, near UV light, electron bean and other high energy radiation etc. Experiments were also perfomed to study the change of photosensitive characteristics upon radiation. The mechanism of image formation and thier applications are discussed.

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Transparent electrically conductive composite films were obtained via vapor phase polymerization of pyrrole into a poly(vinyl chloride) (PVC) matrix containing FeCl₃. The effects of water and of organic solvents on polymerization have been investigated (Fig.2, Fig.3). It has been found that the conductance of films increases in the presence of both water vapor and of good solvents or swelling agents for PVC (Fig.3). The conductivity of the films rises with reaction time and the increase rate in conductance is higher with higher FeCl₃ concentration (Fig.1). The production of HCl was monitored by two methods, namely by precipitation of AgCl in an aqueous solution of silvernitrate, and by the increase in conductance of an aliquot of distilled water which has been placed into the reaction chamber (Fig.7). On the basis of our experimental results, we propose a reaction mechanism (Fig.9) which explains the observed increase of conductance with time (Fig.8). A universal kinetic formula has been derived which relates the increase of electrical conductance with other parameters characterizing the boundary conditions of the polymerization.

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Photopolymerizations of several systems consisting of electron-donor monomers and electron-acceptor monomers have been studied for the purpose of understanding photochemical reactions on the basis of the concept of charge- transfer, searching for new photopolymerization systems that are not subject to oxygen inhibition, and elucidating reaction pathways and mechanisms.
As an extension of our studies on photopolymerizations of N-vinylcarbazole (VCZ) in the presence of amines, photopolymerization of the VCZ -N, N-diethyl- aminoethyl methacrylate (DEAEM) system has been studied. Photoradical copolymerization proceeded by irradiation of the VCZ-DEAEM system, where VCZ and DEAEM function both as coinitiators and monomers. It was found that the polymerization is accelerated in the presence of oxygen when the monomer feed mol ratio is rich in DEAEM. A new multifunctional monomer containing an alkylamino group, N-methyl-N, N-diethanolamine dimethacrylate (MDEADM), has been prepared, and photopolymerization of the VCZ-MDEADM system has been studied. The results show that the photoradical polymerization is not strongly retarded by oxygen, producing gels without the addition of other multifunctional monomers. It is suggested that initiating free radicals in these systems are produced by the reaction of the excited triplet-state VCZ with the ground-state DEAEM or MDEADM via charge-trans er interactions. The results of other photopolymerization systems, VCZ-maleic anhydride (MAn), VCZ-fumaronitrile (FN), 2-vinyl- naphthalene (VN)-MAn and VN-FN systems are briefly described. The photochemical reactions of the VCZ-MAn and VCZ-FN systems involve cationic homopolymerization of VCZ, cyclodimerization of VCZ and 1:1 alternating radical copolymerization of VCZ with MAn or FN. The reaction course and rate depend strongly on the basicity and polarity of solvents.

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