Photo-initiated crosslinking of epoxides is very interesting from the viewpoint of application to organic coatings and photoresists. Although alkyl amines are known to be useful as crosslinking reagents for epoxides, the photochemical formation of alkyl amines which are convenient as crosslinking reagents is not known. Sakuragi et al? reported that in the photolysis of 0-acetyl benzophenone oxime (l), N-methyl benzophenone imine (2) was formed in 23% yield. The photoreaction was thought to proceed as shown in eq. (1).

IntroductionIn a previous paper') we reported that pendent amino groups can be introduced by photolysis of pendent acryloxyimino (AOI) groups *) followed by hydrolysis, and that the pendent amino groups are effective in crosslinking of epoxides. In the course of the studies of the formation of pendent amino groups, described above, we noticed that the efficiency of their formation depends on the main chain structure (R in 3; see Scheme I ) , which shows the outline of the photoreactions of polymers bearing A01 groups.This paper describes the effect of main chain structure on the formation of amino groups.Experimental part 0-acryloyl acetophenone oxime (la) and 0-methacryloyl acetophenone oxime (1 b) were prepared by reaction of acetophenone oxime with acryloyl chloride and methacjloyl chloride, respectively, by a method similar to that described in the previous paper*). l a : m. p. 59 -60°C; 1 b: m. p. 46-47 "C. Styrene (2) was purified by the usual way.Copolymerization: Copolymers. poly(1 a-co-2) (3 a) and poly(1 b-co-2) (3 b), were prepared by solution polymerization in benzene under nitrogen at 60°C in the dark, using 0,2 wt.-Yo 2,2'azoisobutyronitrile (AIBN) as initiator. Molecular weights of the prepared polymers were measured by GPC. The contents of monomeric units of l a and 1 b in the copolymers 3a, b were determined by their elemental analyses. Composition and physical properties of the copolymers are shown in Tab. 1. Films were prepared from a polymer solution in benzene in a Petri dish. Benzophenone (BP) (10 wt.-To) was added as sensitizer to the polymer solution. The thickness of the films was about 30-40 pm.Photoreactions: A high pressure mercury lamp (Ushio UM102) was used as a light source. The applied wavelength was 366 nm (separated by the use of a Toshiba UV-DlB filter). The distance between films and lamp was 7 cm, and the films were irradiated at room temperature. The degree of decomposition of A01 groups was determined by following the change of the *) Strictly: Alkylideneiminooxycarbonyl groups. 0173-2803/88/$01 .oO 520 K.-H. Song, M. Tsunooka, M. Tanakaabsorbance of the carbonyl groups at 1760 cm-' in the IR spectra of the polymer films before and after irradiation. Samples for elemental analyses were prepared by precipitation of the irradiated copolymers from THF/CH30H solutions to remove the sensitizer and lowmolecular-weight compounds formed after irradiation. The alkylideneimino groups formed after irradiation easily change to amino groups by hydrolysis with water. The contents of double bonds were determined by comparing the ratio of the absorbance of double bonds (1 640 cm-' or 970 cm-I) to that of the monomeric units of styrene (1495 cm-I) as an internal standard with a working curve, prepared by the use of the model compounds 2-ethyl-1-hexene (1 640 cm-I) or 2-octene (970 cm-I), in polystyrene.The contents of amino groups in the irradiated polymers were determined by calculation based on the contents of undecomposed A01 groups and double bonds, determined by the IR spectra, assuming...

SynopsisPhotomodifications of polymer surface are investigated from the viewpoint of dyeing of the irradiated polymer surface. For this purpose, several kinds of acryloyl acetophenone oxime (AAPO) copolymers are prepared. As the other monomer components, methyl methacrylate (MMA), styrene (St), 2,3-epoxypropyl methacrylate (EPMA), 2-hydroxyethyl methacrylate (HEMA), N-vinyl pyrroridone (NVP), and n-butyl methacrylate (BMA) are used. In the photolysis of acyloxyimino (AOI) groups in AAPO copolymers, alkylimino groups can be introduced very effectively, which can be easily transformed to ammonium groups by hydrolysis in an aqueous solution of HCl. The surface of AAPO copolymers becomes dyeable with an acid dye (Congo Red) by the irradiation followed by HCI treatment and the degree of dyeing of the surface depends on not only the contents of ammonium groups but also the physical properties of the other monomer components. Although the hydrophilic or polar monomers such as NVP, HEMA, and MMA are cooperative for dyeing, the hydrophobic monomer such as St decreases the function of ammonium groups for dyeing. Although the undecomposed AAPO components in AAPO-MMA do not affect the degree of dyeing up to 24.5 mol % of AAPO contents in AAPO-MMA copolymers, they show the inhibition effect for dyeing of AAP0(38.8)-MMA a t an earlier stage in irradiation. Aromatic moieties in AAPO are thought to inhibit the dyeing.

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