• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.945-953
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• 1997

Aromatic polyetherimide membranes were prepared by dry/wet phase inversion method and investigated regarding the pervaporation characteristic of water-alcohol mixtures by using the permselective property of imide group and the structure modification of skin layer of the membrane. The membrane selectivity increased with the reaction time of surface-modification, to some extent, and the density of top layer tends to increases with increasing the reaction time. In the case of dense membrane, the separation factor was 160 and 2000 for 90wt% ethanol mixture and 90wt% isopropanol solution, respectively, which implies that aromatic polyetherimide has a high permselectivity. The temperature dependence of permeation flux seems to follow an Arrhenius type at the temperature range of ($40^{\circ}C-70^{\circ}C$).

• Journal of Conservation Science
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• v.32 no.2
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• pp.249-259
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• 2016

Effect of the flame retardants on Dancheong is studied in the present work. Two kinds of flame retardants were applied on Dancheong specimens and compared with control groups on which distilled water was applied instead of the flame retardants. The flame retardants enhanced the hygroscopic property of the surface of Dancheong. Furthermore, the added flame retardants reacted with oyster shell white($CaCO_3$) and lead red($Pb_3O_4$), producing new chemical compounds like Calcium phosphate tribasic and Lead Phosphates which make the painted layer of Dancheong dissolving and whitening over certain period of time. When applied in excessive amount and exposed in repetitive wet and dry condition, especially, they aggravate the surface problems significantly. These results will provide a good reference on the study of the discoloring/whitening effect of Dancheong layers at many traditional wooden building in Korea.