[in Japanese]

View full abstract

Three kinds of acrylonitrile - styrene (AN - ST) copolymers with different molar ratios were preparedand reacted with superoxide anion (O₂^_??_) generated from electr o-chemical reduction of O₂^_??_ and KO₂ in dimethylformamide (DMF) solution at 40°C under nitrogen atmosphere. Molecular weight of the polymers decreased with increase in O₂ concentration. IR and UV spectroscopies indicated the formation of hydr oxyl, carbonyl, α, β- unsaturated carbonyl, and polyene structures. These change s are largely dependent on the AN composition in the polymers and O₂^_??_ concentration. Similar results were observed in both reaction systems of electrochemically generated O₂^_??_ and KO₂. The reaction mechanisms were discussed on the basis of the obtained results.

View full abstract

Weather resistance of Japanese lacquer films prepared by adding some amount of urushiol was evaluated by thermal and mechanical methods. Urushiol was extracted from a raw Japanese lacquer with acetone and added to a raw Japanese lacquer or a refined Japanese lacquer, followed by the formation of films from these mixed lacquers. The films were exposed to outdoor, and taken out for given periods of time. Thermal and mechanical properties of the films were examined with the differential scanning calorimeter (DSC), the themogravimetric analyzer (TGA) and the tension tester. In general weather resistance decreased with exposure time. This would be mainly dur to occurences of crach and pinhole caused shrinhage of the films. The films became completely brittle at six months or at 600hours of daylig ht. This result meanos that Japanese lacquer films lose its coating characteristics within a year, when those are exposed directly to sun light.

View full abstract