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Tytuł:
Współczesne surfaktanty i ich struktury micelarne tworzone w roztworach wodnych
Currently available surfactants and their micellar structures formed in aqueous solutions
Autorzy:
Jakubowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/172031.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
surfaktanty
ciecze jonowe
surfaktanty funkcjonalizowane surfaktanty polimerowe
techniki pomiarowe
struktury micelarne
surfactants
ionic liquids
functionalized surfactants
polymeric surfactants
measurement techniques
micellar structures
Opis:
This article presents currently available surfactant ionic liquids as well as functionalized and polymeric surfactants. Ionic liquids (ILs) are organic salts of melting points below 100°C. They have attracted much attention due to their unique physicochemical properties such as low volatility, high thermal stability, low toxicity, high ionic conductivity, capacity to dissolve organic, inorganic and polymeric materials [1]. ILs can be used as “green” solvents in electrochemistry, extraction, chromatography, catalysis, chemical and enzymatic reactions, and synthesis of new materials [2–4]. Ionic liquids are less corrosive than classical molten salts and therefore are used as electrolytes in batteries or solar cells [5]. Like other salts, ionic liquids are formed by ions but at least one of them is an organic ion. Moreover cations and anions differ significantly in their geometrical characteristics [1]. ILs with long alkyl chains and pronounced hydrophilic and lipophilic molecular fragments have an obvious amphiphilic nature and are called the surface active ionic liquids, SAILs, because they show combined properties of ILs and surfactants [6]. Recently, there is ever-increasing interest in SAILs based on gemini surfactants (Figs 6 and 7 [21, 22]), dodecyl sulfate, DS (Fig. 8a) and aerosol-OT, AOT (Fig. 8b) anions [23–25], alkylpyridinium (Fig. 1b [11]), imidazolium (Figs 1a and 3 [13, 14, 16]), alkylpyrrolidinium [17, 18], and diisopropylethylammonium, DIPEA [19] cations. Apart from SAILs, in recent years an attention has also been paid to functionalized surfactants such as: bolaform surfactants [32], supra-long chain surfactants [35, 36], calixarene-based surfactants (Fig. 9 [33]). Surfactants of the above types of SAILs and functionalized surfactants have been synthesized and their micellar structures formed in water have been studied. For example, very interesting vesicle systems were observed in aqueous solutions of diisopropylethylamine alkyl carboxylates, [DIPEA]+[CnH2n+1COO]–, for n = 3–9 (Fig. 5 [19]) and in aqueous solutions of the surfactant mixture composed of N-dodecyl-N-methyl-pyrrolidinium and sodium dodecyl sulfate (Fig. 4 [18]). It was found that 1-hexadecyl-3-methyl-imidazolium chloride in aqueous solutions underwent the phase (micellar) transformations upon cooling (Fig. 2 [13]). An important group of polymeric surfactants attracting a great interest in literature is that of triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), often abbreviated as [EO]a-[PO]b-[EO]a. Recently, these copolymers, also called poloxamers, have been proposed for pharmaceutical use [37–40]. These nonionic surfactants form micelles in aqueous solutions with a core containing the hydrophobic PO blocks and a shell made up of the hydrated EO blocks [41]. The subject of current studies include: the interactions between poloxamers and anionic surfactant, SDS in aqueous solutions [ 42–47], micellization of poloxamers in mixtures of water and organic solvents [48], comparison of association properties of diblock and triblock copolymers [49]. The paper also presents the experimental methods used recently to study surface activity, aggregation behaviors, and micellar structures of surfactants in water.
Źródło:
Wiadomości Chemiczne; 2013, 67, 11-12; 981-1001
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Domieszki stosowane w procesie drążenia tuneli
Chemical additives used in tunnel driving processes
Autorzy:
Kleen, E.
Wasąg, T.
Chodyń, W.
Powiązania:
https://bibliotekanauki.pl/articles/365625.pdf
Data publikacji:
2017
Wydawca:
Nowoczesne Budownictwo Inżynieryjne
Tematy:
drążenie tuneli
urobek
środki powierzchniowo czynne
stabilizator polimerowy
zaprawa
tunneling
output
surfactants
polymeric stabilizer
mortar
Opis:
Jedną z najczęstszych metod drążenia tuneli jest metoda równoważenia ciśnienia gruntu EPB (Earth Pressure Balance). Jest to technologia, w której wydobyty materiał zostaje zmodyfikowany domieszkami i dodatkami chemicznymi. Celem modyfikacji jest nadanie urobkowi odpowiedniej konsystencji, aby z jednej strony zapewnić hydrostatyczne podparcie czoła wyrobiska, z drugiej umożliwić transport przenośnikiem śrubowym i dalej taśmociągiem do składowisk. Domieszki modyfikujące urobek to środki powierzchniowo czynne, polimery i stabilizatory.
One of the most frequently used tunnel driving methods is the EPB (Earth Pressure Balance) method. It is a technology in which the excavated material is modified with chemical additives and additions. The objective of such modification is to obtain the landing's proper consistence, so as, on one hand, to provide for hydrostatic support of the tunnel face, and, on the other, to make it possible to transport the material via a screw conveyor and further on using a belt conveyor flight to dumps. Excavated material modifying additives comprise surfactants, polymers and stabilizers.
Źródło:
Nowoczesne Budownictwo Inżynieryjne; 2017, 2; 64-68
1734-6681
Pojawia się w:
Nowoczesne Budownictwo Inżynieryjne
Dostawca treści:
Biblioteka Nauki
Artykuł
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