硬質塩化ビニル板に対する硫酸の拡散と脱塩酸

概要

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It is well known that the creep rupture behavior of rigid polyvinyl chloride (PVC) is brittle in conc. sulphuric acid. Although the mechanism of the fracture is not yet clarified well, the diffusion and the chemical reaction of sulphuric acid in PVC are considered important factors. In this paper the diffusion of sulphuric acid and the dehydrochlorination in a rigid PVC plate were studied under unloaded and loaded conditions at temperatures of 30' to 80℃. The concentration of sulphuric acid and residual chlorine in PVC were determined by the flaskcombustion method. The results obtained are as follows : (1) The concentration gradient of sulphuric acid near the surface of PVC plate increases with increasing temperature and the surface concentration tends to increase with immersion time. The concentration distribution has an anomalous peak below the depth of 0.1 mm in the case of the immersion above 70℃. (2) The diffusion of sulphuric acid depends on both tensile and compressional stresses. Its dependence decreases with increasing temperature. (3) The dehydrochlorination of PVC plate following the diffusion of sulphuric acid occurs only near its surface as in the case of the diffusion.
社団法人日本材料学会の論文
1977-02-15