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  • amphiphilic polymer  (3)
  • Chemistry  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Highly hydrophobically modified polyelectrolytes: Field variables to control emulsion type (1998)
    Springer
    Colloid & polymer science 276 (1998), S. 945-948 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Emulsion type ; amphiphilic polymer ; polyelectrolyte ; polymeric surfactant ; balanced copolymers
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Highly hydrophobically modified (with n-dodecylamide chain) linear poly(acrylic acid)s (HHMPAAH) and poly(sodium acrylate)s (HHMPAANa) with various degrees of grafting (τ) were synthesized and used as emulsifiers of the n-dodecane/water system. The type of emulsion, oil in water (O/W) or water in oil (W/O), was investigated as a function of the polymer chemical structure (τ, salt or acid form of the copolymer) and aqueous phase electrolyte concentration (NaNO3). Increasing τ and/or salt concentration was found to favor the formation of inverse emulsions. Direct liquid–liquid dispersions are more likely to form with poly(sodium acrylate)s than with poly(acrylic acid)s. Hence, field variables such as τ, pH and ionic strength are relevant parameters to control emulsion type. Moreover, a balanced polyelectrolyte neither soluble in oil nor in water was synthesized for the first time. With this original emulsifier, the dispersion type was found to change from O/W to W/O with polymer salting out. The work provides convenient model system for fundamental studies of polymer conformation at liquid–liquid interfaces.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960050332
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  • 2
    Digitale Medien
    Digitale Medien
    Highly hydrophobically modified polyelectrolytes stabilizing macroemulsions: relationship between copolymer structure and emulsion type (1999)
    Springer
    Colloid & polymer science 277 (1999), S. 89-94 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Key words Emulsion type ; amphiphilic polymer ; polyelectrolyte ; polymeric surfactant ; balanced copolymers ; HLB scale
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract The types of emulsions, oil (n-dodecane) in water (O/W) or water in oil (W/O), stabilized with highly hydrophobically grafted linear poly(sodium acrylate)s, were investigated as a function of polymer chemical architecture. Consequently, a large number of macroemulsifiers, covering a wide range of hydrophobicity, were synthesized by changing the degree of grafting (τ), length (n) and type (single- versus twin-tailed) of the hydrophobic moiety. Monovalent salt (NaNO3) concentration was used as a probe to adjust and hence to estimate the hydrophile-lipophile balance (HLB) of each copolymer. τ, n, type of graft and electrolyte concentration were identified as field parameters to control emulsion type. In general, decreasing either τ or n was found to favor the formation of direct emulsions. Inverse dispersions were preferentially formed with twin-tailed rather than single-tailed copolymers. Moreover, the types of emulsions stabilized with well-balanced polyelectrolytes can be flipped from O/W to W/O with increasing salt concentration. Finally, following the Davies concept, a HLB scale for polymers was created from a comparison with surfactants of nearly identical chemical structure.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s003960050372
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  • 3
    Digitale Medien
    Digitale Medien
    Emulsions stabilized with hydrophobically modified poly(acrylic acid) (1997)
    Springer
    Colloid & polymer science 105 (1997), S. 228-238 
    Details
    ISSN: 1435-1536
    Schlagwort(e): Emulsion ; amphiphilic polymer ; associative polymerstability ; rheology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Maschinenbau
    Notizen: Abstract Hydrophobically Modified (with alkylamide chain) linear Poly(acrylic acid) Sodium Salt (HMPAANa) of various degree of grafting (τ) and alkyl chain length (n) were synthesized and used as emulsifiers ofn-dodecane/water (NaNO3 10−3M) system. Stability and flow properties of the resultingn-dodecane in water emulsions (dispersed phase volume fraction=0.5) were investigated as a function ofτ (τ=0 to 10% in mol),n (n=12, 18) and polymer concentration (0–10%). It was clearly shown that viscosification (via an associative mechanism of HMPAANa) of the external phase of emulsions is a key factor to explain dispersions breakdown. However, a complete description of the phenomenon could not be achieved without considering the adsorption of the polymer at the liquid-liquid interface which depends closely onτ andn. More generally, the behavior of emulsions was found to be described adequately by the degree of hydrophobicity of HMPAANa's using a simple model conjugating the effects ofτ andn. As a matter of fact, the model was also found to provide a satisfactory description of HMPAANa's aqueous solutions as well, so that a good picture of emulsions properties can be deduced from the polymer behavior in water.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01188956
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  • 4
    Digitale Medien
    Digitale Medien
    Miscibility behavior of ternary polymethacrylate-based blends (1993)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 44 (1993), S. 307-312 
    Details
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The miscibility behavior of ternary poly(vinyl chloride)/poly(n-propyl methacrylate)/poly(n-amyl methacrylate) (PVC/PPMA/PAMA) and poly(vinyl chloride)/poly(n-butyl methacrylate)/poly(n-amyl methacrylate) (PVC/PBMA/PAMA) blends was investigated by differential scanning calorimetry. In both systems, a binary mixture of the two polymethacrylates is totally immiscible (PPMA with PAMA, and PBMA with PAMA). For PVC/PPMA/PAMA blends containing less than 70% PVC, the immiscible phase consists of two coexisting binary PVC/PPMA and PVC/PAMA phases. For an equal amount of the two polymethacrylates in the ternary blend, the PVC/PPMA phase contains 65% of the total weight of PVC and the whole quantity of PPMA; the total amount of PAMA mixes with the remaining 35% PVC to form the PVC/PAMA phase. In contrast, the miscibility zone is predominant in the ternary PVC/PBMA/PAMA system, since blends containing 30% or more of PVC exhibit a single glass transition temperature. In the immiscibe zone, the PVC is distributed equally between PBMA and PAMA, which is in contrast to the 65%-35% distribution found in the previous system. These results are consistent with the differences of miscibility observed in the binary PVC/polymethacrylate blends discussed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/actp.1993.010440608
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