Won-jae Park , Seung-kak Yang

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Abstract

A strain of Pseudomonas aeruginosa was isolated from the spoiled product and its characteristics on various formaldehyde-releasing preservatives were investigated. This strain, P. aeruginosa FR, could utilize 1.0% of imidazolidinyl urea and 2% of DMDM hydantoin as a sole carbon and nitrogen source in the minimal salts medium. With the growth of the strain in minimal salts medium containing imidazolidinyl urea, formic acid was initially accumulated according to the decrease of formaldehyde concentration. It was suggested that formaldehyde dehydrogenase was involved in this oxidation process and could catalyze formaldehyde, imidazolidinyl urea, DMDM hydantoin and quaternium-15, but not bronopol. MICs of this strain to each preservative were 0.03% in formaldehyde, 1.0% in imidazolidinyl urea, 0.2% in DMDM hydantoin, 0.2% in quaternium-15 and 0.1% in EDTA-2Na. But the MICs were diminished about ten times when 01% of EDTA-2Na was added to the preservative systems. In actual challenge test, the eyeliner and the pack which contained paraben and imidazolidinyl urea were not able to be protected from this strain, but when 0.05% EDTA-2Na was added the products were sufficiently preserved.

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정광수 Kwang Soo Jung

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Abstract

The decreased preservative effect by tale and TiO₂ for emulsions obtained with polyoxyethylene surfactant was studied by various analytical methods and biological test. The preservative effect of methyl p-hydroxybenzoate was decreased by the addition of talc and TiO₂ and this result was attributed to the adsorption of methyl p-hydroxybenzoate on them. Talc exhibited more decreased preservative effect than that of TiO₂. The amount of the adsorption of methyl p-phydroxybenzoate by talc at 20℃ could be represented by the following equation; a=11.511C^0.747

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이충남 Choong Nam Lee

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Abstract

The effect of dispersed phase on the stability of emulsion system with polyoxyethylene dodecyl ethers and their variation of ethylene oxide moles was studied by such methods as interfacial tension measurement, centrifugation and droplet size variation with time. The experiments showed that, in interfacial tension measurement, long chain alkanols into dispersed phaes are more effectively adsorbed onto interface, while long chain alkanes nearly not, and in centrifugation, dispersed phase with alkanols is less separated than that with alkanes. On the other hand, alkanes help more stabilyzing emulsion than alkanols in droplet size variation. And the addition of NaCl or Urea, and variation of E.O. moles have very slight effects on the stability with alkanes than with alkanols. Moreover, the longer carbon chain length is, dispersed phase is more effective on emulsion stability. Supposed from these facts is that more stable emulsion can be made with alkanes which retard molecular diffusion by water solubility decrease rather than alkanols which raise resistance to coalescence by rigid interfacial mixed monolayers formation. In conclusion, the stabilities of these emulsions are proved to be more influenced by molecular diffusion than coalescence.

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김영대 Young Dae Kim

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Abstract

This study is concerned with the ion exchange adsorption of benzalkonium chloride solution in a fixed-bed of cation exchange resin, Amberlite 200. The effects of concentration and linear velocity of benzalkonium chloride solution on adsorption capacity and lost bed height, f.zaj were studied. The breakthrough curves were obtained experimentally. From the curves, the values of the breakpoint capacity, lost bed height, f.za^ and dynamic, equilibrium ion exchange adsorption capacity at exhaustion were calculated. The average lost bed height, f.za，was about 9.44 cm. The equilibrium ion exchange capacity at exhaustion was increased with the decrease of linear velocity at a constant concentration and also with the decrease of concentration at a constant linear velocity. It was notable that at a low concentration the equilibrium ion exchange capacity at exhaustion in a fixed-bed was close to those obtained in a static, batch experiment. However it decreased rapidly as the critical micelle concentration (CMC) is approached, and remained almost constant above CMC. The maximum dynamic, equilibrium ion exchange capacity in the fixed-bed was 23.2% of the theoretical ion exchange capacity, 4.3 meq/g (dry), of Amer- lite 200,and 65.1% of the equilibrium ion exchange capacity, 1.56meq/g(dry) from static, batch experiment.

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신인목 In Mok Shin

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Abstract

This study was carried out to study the effects of additives and structure of nonionic surfactants on the stability of OAV emulsions which are composed of octane, water and polyoxyethylene nonylphenyl ethers (NP). Their effects on the interfacial behavior was also considered. Octane alone or octane + additives were used as the dispersed phase in OAV emulsions and 0.03 mol dm-^ of long chain alkanes (D ode cane, Hexadecane) or long chain alkanols (Dode-canol, Hexadecanol) were used as additives. The experiemental results, from the measurements of surface tension, variation of mean droplet volume and separation rate of OAV emulsions were shown that the stability decreases with increasing the ethylene oxide (EO) moles in NP and that the (cmc) increases with increasing the EO moles. From the measurements of interfacial tension and centrifuge for the octajie/NP-20 emulsion systems, it was found that the addition of alkanols is more effective than the addition of alkanes to stabilize the emulsion system. On the other hand, from the measurements of variation of mean droplet volume and separation rate of octane/NP-20 emulsions, it was found that the addition of alkanes are more effective than the addition of alkanols on the stability of OAV emulsions, and the stabilizing effects were increased with increasing the chain length of the additives. The results suggest that the main cause of instability in octane/NP-20 emulsion systems may come form molecular diffusion rather than droplet coalescence. The molecular diffusion is dependent on the solubility of the dispersed phase and is, therefore, larger for alkanols and shorter chain alkane.

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이능안 Neung-an Lee

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Abstract

Reactions of trimethylsiyldiethylamine, trimethylgermyldiethylamine, tri- methylstannyldiethylamime, and trimethylplumbyldiethylamine with pheny- lisocyanate were carried out at various temperatures for 4 days in sealed ampoules. In these all reactions, triphenylisocy an urate which is cyclictrimer of pheny- lisocyanate was mainly produced at low temperature, and diphenylcarbodi- imide was formed along with triphenylisocyanurate at high temperature, whereas, in the ease of trimethylsilydiethylamine, 1,3,5-tripheny 1-2, 4 6- tris (phenylimino) hexahydro-1,3,5-triazine and N, N’-diphenyluretidine-2,4- dione were given together with the compounds described above. The reactivity of group IVa Organometalamines for phenylisocynate were the fellowing order. Me₃pbNEt₂>Me₃SnNEt₂>Me₃GeNEt₂>Me₃SiNE₂ These group IVA organometalamines were only acted as catalysts.

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