In order to develope the precipitation process of polytetrafluoroethylene(PTFE) dispersion using nonionic surfactants, the effect of the surfactants and additives on the cloud point(CP) of the nonionic surfactant solution was investigated. The nonionic surfactants used were a series of t-octylphenoxy polyoxyethylene ethers(Triton X114, Triton X100, HS208, and HS215) and their mixtures. The additives were ionic surfactants(ammonium perfluorootanoate and sodium dodecyl sulfate) and electrolytes((NH4)2S2O8, NH4F, NaCl, MnCl2, and CrCl3). In this study, it was observed that, as the concentration of the nonionic surfactants increased, the CP decreased sharply, going through a minimum at a low concentration of the nonionic surfactants and then increased slowly at a higher concentration. It was also shown that the higher value of CP was obtained as the number of EO group of the nonionic surfactant increased. Various additives added to these surfactant solutions significantly affected the CP. In general, the CP was decreased by the addition of the electrolytes; the univalent cations of the added electrolytes more actively decreased CP than the polyvalent cations. The order of decreasing effect on CP was NaCl>MnCl2>CrCl3. However, the CP increased remarkably by the addition of the ionic surfactants; the fluorinated surfactant(ammonium perfluorootanoate) was more effective than the hydrocarbon surfactant(sodium dodecyl sulfate).

비이온 계면활성제 수용액의 담점 특성을 이용한 폴리테트라풀루오로에칠렌(PTFE)의 농축공정 개발을 위한 기초연구로서, 비이온 계면활성제 수용액의 담점에 관한 농도 및 첨가제 영향을 고찰하였다. 사용한 비이온 계면활성제는 C8H17(C6H6)(C2H4O)nOH 형태(Triton X114(n=8), HS208(n=9), Triton X100(n=9.5), HS215(n=15) 및 그 혼합물이었으며, 첨가제로는 음이온 계면활성제(불소계: C7F15COONH4, 탄화수소계: C12H25OSO3Na)와 무기염((NH4)2S2O8, NH4F, NaCl, MnCl2, CrCl3)을 사용하였다. 실험결과, 비이온 계면활성제 수용액에서 농도에 따른 담점은 저농도에서 최저점을 가진 후 서서히 증가하는 경향을 나타내었으며, 사용한 비이온 계면활성제의 친수성기인 옥시에틸렌이서(OCH2CH2)n의 n값이 증가함에 따라 더 높은 담점을 나타내었다. 첨가제의 영향은 무기염을 첨가한 경우, 그 종류에 관계없이 첨가량을 증가시킴에 따라 담점은 저하되는 경향을 나타내었는데, 특히, 염소(Cl)이온의 전하크기가 작을수록(NaCl>MnCl2>CrCl3) 담점은 더 낮아졌다. 이와는 반대로 음이온 계면활성제의 첨가에 따라 담점은 급격히 증가하는 경향을 나타내었는데, 불소계가 탄화수소계에 비해 상대적으로 더 높은 담점을 나타내었다.