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Titolo:
Dynamic surface tension of dilute aqueous solutions of nonionic cellulose derivatives in relation to other macromolecular characterization parameters
Autore:
Persson, B; Nilsson, S; Bergman, R;
Indirizzi:
Univ Uppsala, Uppsala Biomed Ctr, S-75123 Uppsala, Sweden Univ Uppsala Uppsala Sweden S-75123 Biomed Ctr, S-75123 Uppsala, Sweden
Titolo Testata:
JOURNAL OF COLLOID AND INTERFACE SCIENCE
fascicolo: 2, volume: 218, anno: 1999,
pagine: 433 - 441
SICI:
0021-9797(19991015)218:2<433:DSTODA>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
ETHYL HYDROXYETHYL CELLULOSE; CHARACTERIZATION PRINCIPLES; INTERFACIAL-TENSION; WATER; SDS; EHEC; MICROVISCOSITY; EQUILIBRIUM; POLYMER; SYSTEM;
Keywords:
dynamic surface tension; nonionic cellulose derivatives; pendant drop method; intrinsic viscosity; molecular weight; diffusion coefficient; cloud point;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Persson, B Univ Uppsala, Uppsala Biomed Ctr, POB 574, S-75123 Uppsala, Sweden Univ Uppsala POB 574 Uppsala Sweden S-75123 23 Uppsala, Sweden
Citazione:
B. Persson et al., "Dynamic surface tension of dilute aqueous solutions of nonionic cellulose derivatives in relation to other macromolecular characterization parameters", J COLL I SC, 218(2), 1999, pp. 433-441

Abstract

The dynamic surface tension of 10 nonionic water soluble cellulose derivatives with molecular weights (M-w) in the range 100,000-1,300,000 has been measured by the pendant drop method at the water/air interface, The surface tension measured after 11.7 h, gamma*, was taken as an apparent steady state surface tension. The gamma* at the highest concentration, 500 ppm, gamma*(500) showed values from 63 to 37 mN/m, and the value of gamma*(500) depends on the hydrophilic/hydrophobic balance of the polymer. The aim of the present work was to discuss the dynamic surface tension in relation to some other characterization parameters, like hi,, diffusion coefficient, intrinsicviscosity ([eta]), cloud point, and degree of hydrophilic/hydrophobic substitution. Dynamic surface tension was shown in a concentration range of 2-10 ppm. The time to reach (gamma(H2O)-gamma*)/2, defined as t(1/2), was found to be inversely correlated both to the diffusion coefficient and to the square of the bulk concentration, which can be expected for a diffusion controlled process. The time t(1/2) showed an approximately linear relationshipagainst [eta](1/3). The pendant drop was found to decrease in volume with time due to the high vapor pressure caused by the curvature of the drop (Delta P = 2 gamma/r(drop)). (C) 1999 Academic Press.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 12:53:37