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Analysis of PVDF Coating Properties with Addition of Hydrophobically Modified Fumed Silica
문명준,이남규,김영훈,임태규,이동욱,손민영 한국부식방식학회 2019 Corrosion Science and Technology Vol.18 No.6
In this study, hydrophobically modified fumed silica was added to the PVDF coating to improve corrosion protection performance. Two types of silane modifiers, trimethylchlorosilane (TMCS) and hexamethyldisilazane (HMDZ), were used for hydrophobic modification of the fumed silica. The composition of modified fumed silica was analyzed by Fourier transform infrared, X-ray photoelectron spectroscopy, and elemental analysis. The dispersion of modified fumed silica in the PVDF coating was observed by the transmission electron microscopy, and the hydrophobicity of PVDF coating was analyzed by the water contact angle. Surface properties were examined by the field emission scanning electron microscopy and scanning probe microscopy. Potentiodynamic polarization was conducted to confirm corrosion protection performance of PVDF coating in terms of hydrophobically-modified fumed silica contents. As a result, the average surface roughness and the water contact angle of the PVDF coating increased with modifier contents. The results of the potentiodynamic polarization test showed an increase of the Ecorr values with increase of the hydrophobicity of PVDF coating. Thus, it clearly indicates that the corrosion protection performance of PVDF coating improved with the addition of the hydrophobic-modified fumed silica that prevents the penetration of moisture into the PVDF coating.
기능성 유기/무기 복합 에폭시 코팅제의 제조 및 접착 특성 연구
문명준,곽삼탁,이정환,이민규,서차수,백재호 한국화상학회 2006 한국화상학회지 Vol.12 No.2
In order to improve adhesion properties and give a toughness of the cured solvent free epoxy system, organic-inorganic hybrid epoxy coatings, which have prepared by adding 3-aminopropyltriethoxysilane(3-APTES) were estimated by UTM test, adhesion test, and the surface hardness test and the physical and chemical behavior of 3-APTES at the interface region was evaluated by XPS and FT-IR-ATR. It was shown that Si atomic ratio of surface without contacting with substrate was higher than the ratio of surface contacted with substrate through the surface analysis. By the addition of 3-APTES Si atomic ratio was totally decreased at both sides of epoxy film and was higher at the contacting surface of substrate than other side. It was found that the free volume and the crosslinking density were simultaneously increased by the silane group of 3-APTES, which has diffused to the inner part of the epoxy film, the flexibility was increased as indicated by the lowering of Tg and adhesion and mechanical strength of film were also improved. 경화된 에폭시의 접착력을 개선하면서 toughness를 부여하기 위해 무용제형의 에폭시 수지에 3-aminopropyltriethoxysilane(3-APTES)를 첨가하여 경화된 유기-무기 복합 에폭시 도막의 인장강도와 접착력, 표면경도를 측정하고, 접착계면에서 3-APTES의 물리화학적 작용은 XPS와 FT-IR-ATR에 의해 조사하였다. 표면분석을 통해 3-APTES가 첨가되지 않은 경우에는 기질과 미접착면의 Si 원소 함량비가 더 크나, 3-APTES를 첨가하게 되면 전체적으로 표면에서 Si 원소 함량비도 감소하면서 기질과 미접착면의 Si 원소 함량비는 기질과 접착면이 보다 더 낮아졌다. 이것은 에폭시 도막의 내부로 3-APTES가 확산이 되면서 silane기에 의해 에폭시도막의 free volume과 경화밀도를 동시에 증가시켜 Tg가 낮아지고 유연성이 증가하면서 동시에 경화밀도는 높아져 접착력, 인장강도가 향상되었다는 것을 알 수 있었다.
Study on the Viscosity of Dilute Aqueous Solution
문명준 釜山工業大學校 1988 論文集 Vol.30 No.-
The viscosity of dilute electrolyte solution is affected by the interaction between ions and water molecules as well as the change of the water structrues around the ion. In the significant structrue theory, these interaction energies must be involved in the sublimation energy which need to form the vacancy of molecular size. Viscosities of NaCl, KCl, KBr, and KI solutions are obtained for various temperatures and concentrations. The calculated viscosities in the dilute solution are in good agreements with the experimental data. It is found that the phenomena of structrue making and breaking of water molecules in the first hydration shell of ion must be quantitatively explained in order to understand the viscosities in the dilute aqueous solution.