화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
HWAHAK KONGHAK, Vol.36, No.2, 215-222, April, 1998
Export Citation
Wicking법에 의한 분체 고분자의 접촉각과 표면자유에너지 결정
Determination of Contact Angle and Surface Free Energy of Polymer Powder by Wicking Method
노승백, 임미애
초록
분체 polymethylmethacrylate(PMMA), polyvinylchloride(PVC)와 polyvinylidenefluoride(PVdF)에 대한 water, glycerol, formamide, diiodomethane, 1,1,2,2-tetrabromoethane, 1-bromonaphthalene과 hexadecane과의 접촉각을 Washburn식을 기본으로 한 wicking법으로 측정하였으며, 필름 형태의 고분자에 대한 유기액체들과의 접촉각과 일치하는 결과를 얻었다. Wicking법으로부터 충전관내의 분체를 적시는 액체의 적심(wetting) 질량과 높이를 측정하여 입자사이의 세공평균반경을 결정하였다 측정된 접촉각으로부터 분체 PMMA, PVC와 PVdF의 임계표면장력(Υc)은 Zisman plot으로 예측하였으며, 각각 43.5, 44.2와 27.7mNm-1 값을 얻었다. 분체 PMMA PVC와 PVdF의 표면자유에너지(Υs)와 그 성분 값들을 기하평균식, van Oss 접근법과 Neumann의 상태방정식으로부터 결정하였으며, 각각 37.0-41.0, 37.0-43.4와 32.3-33.1 mNm-1 값으로 필름 형태의 PMMA, PVC 및 PVdF의 Υs 값과 일치하는 결과를 얻었다. 실험결과로부터 실험에 쓰인 고분자들은 비극성, 염기성 성질을 가지며, PVdF는 PMMA와 PVC에 비해 극성(polar) 성질이 큰 고분자임을 알 수 있었다. 또한, 분체 PMMA, PVC 및 PVdF와 물, 그리고 유기액체와의 고체-액체 계면자유에너지(ΥSL)와 점착일(WA)을 계산하여 얻어낼 수 있었다.
The values of contact angle on powder type polymethylmethacrylate(PMMA), polyvinylchloride(PVC) and polyvinylidene fluoride(PVdF) were determined by wicking method on the basis of Washburn equation for water, glycerol, formamide, diiodomethane, 1,1,2,2-tetrabromoethane, 1-bromonaphthalene, and hexadecane. Measured values were consistent with these of film types polymers. Average pore radius was determined from measured values of wetting height and mass of liquid in the powder packed column. From the measured contact angle, the values estimated of Υc of powder PMMA, PVC and PVdF by Zisman plot were 43.5, 44.2, and 27.7mNm-1, respectively. The values of Υs of powder PMMA, PVC and PVdF were determined by using geometric mean, van Oss approach method and equation of state of Neumann, 37.0-41.0, 37.0-43.4 and 32.3-33.1mNm-1, respectively. From the results, it was considered that powder PMMA and PVC have a nonpolar and basic characteristics, powder PVdF has a weak polar characteristics. The solid-liquid interfacial free energy(ΥSL) and work of adhesion(WA) were also determined for powder PMMA, PVC, and PVdF to water and organic liquids.
Keywords:Wicking Method;Contact Angle;Pore Average Radius;Critical Surface Tension;Surface Free Energy
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