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The influence of surface treatment with triethoxymethylsilane and triethoxyethylsilane sols on the permeability of powder coatings

Warszyński Piotr, Szczepanowicz Krzysztof, Mordarski Grzegorz, Szczęch Marta, Nowak Paweł, Lipka Magdalena, Nowak Daria, Sałek Tomasz, Stańczyk Rafał

Ochrona przed Korozją

2023

nr 7

192--196

The objective of the research described in the present paper is the powder coatings prepared with the use of the low-cost polyester resins and their possible application on aluminum elements for the service in the harsh environment: marine and offshore atmosphere, swimming pools where chlorine is used for disinfection, chemical industry. Pores, cracks and pinholes in the final powder coating are the weak points of an undamaged coating, the points where the process of corrosion could begin. Clogging them should decrease the probability of blistering due to hydrogen evolution caused by the contact of the metal surface with the aggressive me- dia. With the application of the electrochemical impedance spectroscopy authors showed that treatment of the surface of a coating with the sol of either triethoxymethylsilane or triethoxyethylsilane causes the decrease in the water uptake in the first step of water sorption by the coating, which was ascribed to the clogging of the pores by the sol particles.

Przedmiotem badań opisanych w artykule są pokrycia organiczne farbami proszkowymi otrzymywane z tanich polimerów poliestrowych oraz możliwości ich użycia do ochrony antykorozyjnej wyrobów aluminiowych przeznaczonych do pracy w agresywnym środowisku: w transporcie morskim, na terenach nadmorskich, w basenach, w których wciąż używa się chloru do dezynfekcji, czy w przemyśle chemicznym. Pory, pęknięcia i dziury w końcowej powłoce proszkowej – to słabe punkty nieuszkodzonej powłoki, w których może rozpocząć się proces korozji. Zamknięcie ich powinno zmniejszyć prawdopodobieństwo powstawania pęcherzy w wyniku wydzielenia się wodoru wskutek kontaktu powierzchni metalu z agresywnymi czynnikami. Za pomocą elektrochemicznej spektroskopii impedancyjnej wykazano, że obróbka powierzchniowa pokrycia proszkowego zolem trietoksymetylosilanu lub trietoksyetylosilanu powoduje obniżenie zdolności pochłaniania wody w pierwszym etapie sorpcji wody przez powłokę na skutek wypełnienia porów i pęknięć w pokryciu cząsteczkami zolu.

Adsorpcja dwufunkcyjnych labilnych surfaktantów kationowych na granicy faz ciecz/gaz : opis za pomocą modelu kwazi-dwuwymiarowego elektrolitu

Frąckowiak Renata, Para Grażyna, Lamch Łukasz, Szyk-Warszyńska Lilianna, Wilk Kazimiera A., Warszyński Piotr

Wiadomości Chemiczne

2021

[Z] 75, 9-10

1119--1155

There is an increasing interest in surfactants that comprise a linkage that breaks down in a controlled way. The most known examples of the cleavage mechanism include acid or alkaline hydrolysis, UV irradiation, enzymatic or heat decomposition. For practical reasons, the labile grouping can be inserted between the hydrophobic tail of the surfactant and the polar head group. Chemically and/or enzymatically induced cleavage of this labile bond would cause the separation of the polar part and the hydrophobic tail and, consequently, change of surface activity, an event usually referred to as the primary degradation of the surfactant. Dicephalic labile cationic surfactants belong to the class of surface active compounds with many potential applications often associated with their biological activity for a wide range of bacteria, viruses, fungi, or algae. Thus, they can be used in disinfecting agents or for protecting against the occurrence of these microorganisms. They adsorb well on negatively charged surfaces, which can be used in the treatment of fabrics. Due to excellent antistatic properties, they can be used for the final rinsing of fabrics, especially synthetic ones. In flotation processes, they can act as collectors, and in catalysis, they can be used as phase transfer catalysts or templates for zeolite synthesis. We present the surface quasi-two-dimensional electrolyte (STDE) model as a universal model for the description of ionic surfactants’ adsorption at fluid interfaces that explicitly considers the electric double formation upon surfactant adsorption. The model was adapted to describe phenomena occurring for adsorption of dicephalic surfactants as counterion specificity or formation of surfactant ioncounterion associates. As an example, we applied the model to explain the mechanism of adsorption at water/air interface of novel dicephalic cationic surfactants, N,N-bis[3,3′-(trimethylammonio)propyl]alkylamide dibromides and N,N-bis[3,3′-(trimethylammonio)propyl]alkylamide dimethylsulfates, both belonging to the class of chemodegradable surfactants having amide bond between two quaternary amine cationic groups and a single hydrophobic tail. Additionally, we used the same model to describe adsorption isotherms of N,N-bis[3,3- (dimethylamine)propyl]alkylamide dichlorides, having as two hydrophilic groups tertiary amines, which charge is pH-dependent. Application of the STDE model allowed an excellent description of experimental adsorption isotherm of dicephalic cationic surfactants and explained the specific features connected with the presence of multicharged headgroup.