Using butyl-2-methylpropionate (BP) and monomeric butoxymethylmelamine (MB) as model compounds for acid-epoxy crosslink (ester bonding) and melamine crosslink respectively, hydrolysis rates of these crosslinks in 70 wt% sulfuric acid have been estimated. BP was dissolved in 70 wt% sulfuric acid at 40°C. The solution was neutralized to stop the hydrolysis after predetermined time. The concentration of 1-butanol in the solution was measured with a gas chromatography. MB was hydrolyzed at -18 and 0°C, and treated in the same manner described above. Hydrolysis rate constants were determined from 1-butanol formation by fitting to the first-order reaction kinetics. The hydrolysis of both compounds was first order reaction with respect to 1-butanol formation. The hydrolysis rate constant of BP at 40°C was 2. 5×10-4s-1, while those of MB at -18 and 0°C were 1. 0 × 10-1 and 2. 8 × 10-1s-1, respectively. An Arrhenius' approximation gave the rate constant for MB at 40°C to be 1. 7 s-1. The hydrolysis rate constant in ester bonding was less than 1/6600 of that of melamine crosslink. It was confirmed that acid-epoxy coatings have excellent resistance to acid rain.
New perfluoropolyethers (PFPE) containing an amino or an amide group at the chain end, F (CF2CF2CF2O) 11CF2CF2 -Y (Y, functional group) have been synthesized and their adsorption properties on silica gel and diamond powder have been investigated by thermogravimetric (TG) analysis and X-ray photoelectron spectroscopy (XPS) measurement. The primary PFPE amide exhibits the highest adsorption amount on silica gel among synthesized PFPEs. It is found that PFPE amide strongly interacts with silica gel surfaces compared with PFPE amine. On the other hand, the highest adsorption amount on diamond powder is obtained for the secondary PFPE amide having a methyl group. The friction coefficient of aluminum plate decreases by the treatment with PFPEs. Almost no dependence of the functional group on the coefficient is found.
SnOx (x =1, 2) particles with high electric conductivity were prepared from tin (II) acetate and antimony (III) chloride in alkaline ethanol-water solution under reflux. Crystal form and crystallite size of nanometer-sized SnOx particles strongly depended on sample preparation conditions such as ethanol to water ratio (Rs), tin acetate to sodium hydroxide ratio (Rc) in media, and Sb content. At Rs= 50/50, SnO2 single crystals of 3-5 nm in diameter were formed at Rc =10, whereas SnO particles of 20-30 nm in diameter were synthesized in addition to SnO2 fine particles at Rc = 15. No precipitate was obtained at Rc = 5 and 25. After heated above 800°C, the electric resistance of SnO2 particles doped with antimony ion (<102cm) became much less than that of non doped SnO2 particles (103-105Ωcm).