The permeation characteristics of cellulose nitrate (CN) -cellulose acetate (CA) blend polymer membranes were investigated by changing membrane preparation methods and permeation condition. The casting solutions were prepared from mixtures of CN-CA, acetone (A), and formamide (FA) in the proportion of 13 : 45 : 42 (wt%). When the CN/CA ratios were varied, there was a maximum value in pure water permeability, and the blend composition having the maximum permeation rate changed with the solvent evaporation period during membrane formation. However, when the aqueous solutions of poly (ethylene glycol) were used as feed, the permeation rates were increased with an increase in the content of cellulose acetate in the blend polymer. In the case of using the aqueous solution of poly (vinyl alcohol) as feed, the permeation rates had the maximum value at the ratio, CN/CA =1/2. From these results, it was found that the fine structures of blend polymer membranes were influenced by the ratio of blend polymer composition and the solvent evaporation period and the interaction between the membrane substrate and the solvent and solute in the feed, also affected the permeation characteristics. The permeation rate was increased with an increase in the operating pressure up to 4 kg/cm2but over 4 kg/cm2the rate began to decrease. The permeation rate was decreased with an increase of the feed concentration and increased with an increase of the operating temperature. These phenomena were discussed from a point of view of the physical and chemical natures of the membrane substrate and feed.
The monomer mixture containing styrene (St) 19. 2 mole %, butylacrylate (BA) 56. 0 mole %, itaconic acid (IA), 11. 0 mole % andβ-hydroxyethylmethacrylate (HEMA) 13. 8 mole % was copolymerized to obtain the uniform composition copolymer by means of monomer dropping type free radical polymerization system in which each monomer was added during the polymerization according to the rate of monomer addition calculated from the multi-components composition scheme. The resulting copolymer compositions in various conversion were measured by means of NMR spectra. Triethyl amine was added to the copolymer to neutralize. Then the curing reagent and pigment of titanium dioxide were added, and the mixture was ball-milled to prepare a paint. The properties of the paint thus prepared were evaluated as the thermosetting white enamel in comparison with the properties of the copolymer obtained from batch type copolymerization system. (1) The resulting copolymer compositions in various conversion were pretty constant. This result means that the aimed uniform composition copolymers can be practically obtained. (2) The paint film based on the uniform composition copolymer was better in the properties of acid resistance and stain resistance than on the copolymer obtained by the batch type copolymerization system. But the solvent resistance, boiled water resistance, mechanical physical properties etc.were almost the same.