For the synthesis of reactive polymers with high adsorption abilities, poly (N-allenylpyrrolidone) was prepared by the radical polymerization of N-allenylpyrrolidone in bulk or in ethanol solution using 2, 2'-azobis (isobutyronitrile) (AIBN) as an initiator at 60°C. The resulting polymer was subjected for the radical addition reaction with dodecanethiol to give the docecylmercapto-grafted poly (N-allenylpyrrolidone). Radical polymerization of vinyl acetate was carried out in the presence of poly (N-allenylpyrrolidone) to obtain poly (vinyl acetate) -grafted poly (N-allenylpyrrolidone).
To modify the aluminum hydroxide surface, the grafting of polymers onto the surface by the polymerization of vinyl monomers initiated by azo groups introduced onto the surface was investigated. The introduction of azo groups onto aluminum hydroxide was achieved by the direct condensation of surface hydroxyl groups with 4, 4'-azobis (4-cyanopentanoic acid) using N, N' -dicyclohexylcarbodiimide as catalyst : The amount of azo groups introduced onto the surface was determined to be 0.41 mmol/g. It was found that the radical polymerizations of vinyl monomers, such as methyl methacrylate styrene, and N-vinylcarbazole, were successfully initiated by azo groups introduced onto the surface and the corresponding polymers were grafted onto the surface. The photopolymerization of vinyl monomers was also initiated by the azo groups introduced onto aluminum hydroxide to give polymer-graf ted aluminum hydroxide. These results indicate that the graft polymerizations are started from surface radicals formed by the thermal or photo decomposition of surface azo groups on aluminum hydroxide and grafted chains are propagated from the surface. In addition, postgraft polymerization of vinyl polymers was initiated by surface grafted chains having pendant peroxycarbonate groups and branched polymer-grafted aluminum hydroxide was obtained. The wettability of aluminum hydroxide was drastically turned from hydrophilic to hydrophobic by the grafting of polymers onto the surface.
A blocking method of carboxylic acids using alkyl vinyl ethers was studied. In this method, carboxylic acids were converted into hemiacetal esters. The vinyl ether blocked carboxylic acid was prepared by the addition of carboxylic acid to an excess of alkyl vinyl ether (×1.5 mol) in the presence of trace amounts of acidic phosphate (0.4 equiv%) at 25°C for 17 h. The deblocking reaction of the vinyl ether blocked carboxylic acid occurred readily at temperatures over 140°C. The activation energy of the deblocking reaction (1. 06 × 105 J/mol) was higher than that of the esterification between carboxylic acid and epoxide (7.91 × 104 J/mol). This result indicated that the deblocking reaction was the rate-determining step in the curing of the vinyl ether blocked carboxylic acid/epoxide system. The blocked carboxylic acid was stable at 50°C up to 30 days. The vinyl ether blocked carboxylic acid/epoxide system was also stable under the same storage condition. By using the vinyl ether blocked carboxylic acids with epoxides, useful one-component coatings can be obtained.
The synthesis of microspheres using tetraethoxysilane (TEOS) was investigated using a roundbottomed tubular reactor (150 mm ext. diam., 1150 mm hieght), which was capacitively coupled with a 13.56 MHz radio frequency generator. Under most experimental conditions, white dust particles were formed at the plasma zone, in the middle of the reactor, and deposited on the bottom of the reactor. SEM observation showed that 0.2 to 0.6 micron diameter microspheres were formed. The powder having different morphologies such as mono-dispersed, chained with several particles and coagulated, and was depended on the experimental conditions.
Anionic dyes can be fixed in chitosan/smectite composite system to give water-insoluble colored materials, which are applicable as pigments harmless to human body when FD & C dyes are used as the anionic dyes. In order to prepare the colored materials, two types of processes, 2- and 1-step ones, were tried. In the 2-step process, chitosan/smectite composite substrate prepared by mixing chitosan acetate solution and Na-montmorillonite suspension was separated, dried and powdered in the 1 st step, and then in the 2 nd step was redispersed in 0.5% acetic acid solution and treated by anionic dyes. In the 1-step process, the composite substrate formed in the suspension was not separated and dyed in situ. The composite substrate in the 2-step process had chitosan intercalated between the silicate layers as single layer or double layers. The double-layer structure was found to be capable of adsorbing anionic dyes, while the single-layer one was not. The layer structure was maintained throughout with the basal spacings expanded by the dye adsorption. On the other hand, the 1-step process gave products poorer in the structural order, but richer in the dye content and stronger in eluting resistance of the dye in salt water. Pigment properties were compared with commercial FD & C aluminum lakes.
Cationic sol was formed by the method of mixing a dilute acetic acid solution of chitosan rapid y with an FD & C dye solution containing the dye anion less than equivalent to the chitosan cation. The sol was fixed by intercalation into silicate layers of montmorillonite, giving water-insoluble colored materials suitable for pigments harmless to human body. When Tartrazine or Sunset Yellow FCF was used, the material obtained had dye content comparable to, and eluting resistance in salt water stronger than those of corresponding aluminum lakes. The intercalation expanded the interlayer spacing by 4.5 to 20A from that of the original montmorillonite. The cationic sol consisted of chitosan bridged by the multidentate dye anions and the higher dye content gave the more densely-bridged chitosan, resulting in smaller interlayer spacings and stronger eluting resistance. Tartrazine which has three functional groups in a molecule to form three-dimensionally bridged sol structure, gave larger interlayer spacings than Sunset Yellow FCF which has two functional groups to form planar sol structure, giving smaller interlayer spacings and stronger eluting resistance. When free amino groups existed in the composite, they expanded the intercalated sol structure, which caused increase in the interlayer spacing along with decrease in the eluting resistance.
Since water-soluble polymers have hydrophilic groups such as carboxyl group and their films exhibit inferior water resistance, thier application to coatings is limited to a small sphere. Among many kinds of onium salts, some aprotic salts are known to be easily decomposed by heating. We have found out that the onium salts synthesized from epoxy compounds with thioethers or tertially amines and carboxylic acids show lower decomposition temperature than 140°C, The effects of the epoxy groups, acids and bases on the conversion to aprotic onium salts and on their thermal decomposition were investigated in detail. The aprotic onium salts synthesized from glycidyl epoxy compound with thioethers and acetic acid were easily dissolved in water and decomposed thermally. It was assumed that their thermal decomposition occurred according to the mechanism of the Hoffmann degradation.
FeCrPC amorphous powders were produced by the two-stage quentching technique consisting of high-pressure nitrogen atomization and melt spinning. These amorphous powders had a flaky morphology like an ellipsoidal disk, of which thickness and diameter were 1-2 pm and 25-150 pm, respectively. The unique morphology with amorphousness of the Fe-based powders was accounted in this process because of the impact flattening of atomized liquid droplets which had been supercooled below the melting temperature. These flaky Fe-based amorphous powders had a high luster.The color on the surface of the flaky amorphous powders can be tailored by heat treatment in air. These powders were expected to be used as a pigment in paint.