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Titolo:
INVESTIGATION OF AQUEOUS-SOLUTIONS BY MODULATED TEMPERATURE DIFFERENTIAL SCANNING CALORIMETRY
Autore:
ALDEN M; HILLGREN A;
Indirizzi:
UNIV UPPSALA,CTR BIOMED,DEPT PHARMACEUT CHEM PHYS & INORGAN CHEM,BOX 574 S-75123 UPPSALA SWEDEN
Titolo Testata:
Thermochimica acta
fascicolo: 1-2, volume: 311, anno: 1998,
pagine: 51 - 60
SICI:
0040-6031(1998)311:1-2<51:IOABMT>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
OSCILLATING DSC; NUCLEATION; GLYCOL; HEAT; ICE;
Keywords:
MTDSC; ODSC; AQUEOUS SOLUTIONS; HEAT OF TRANSFORMATION; CRYSTALLINITY; DEGREE OF OSCILLATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
11
Recensione:
Indirizzi per estratti:
Citazione:
M. Alden e A. Hillgren, "INVESTIGATION OF AQUEOUS-SOLUTIONS BY MODULATED TEMPERATURE DIFFERENTIAL SCANNING CALORIMETRY", Thermochimica acta, 311(1-2), 1998, pp. 51-60

Abstract

The influence of variables on the observation of thermal events and on the determination of heats of transformation at freezing and thawingin aqueous solutions was investigated using modulated temperature differential scanning calorimetry (MTDSC, ODSC). The investigated systemswere pure water and dilute aqueous solutions of polyethylene glycol (PEG) 6000, The influence of eleven combinations of frequency, amplitude and underlying heating rate was analyzed in heating-cooling scans. The selection of variables had a great impact on the shape of the c(p) component curve as well as on the amount of heat expressed by the c(p)component, Delta H-c, of the thermal event. The conventional Delta H-values were not influenced to the same extent. The ratio Delta H-c/Delta H of the melting process might be an expression of the degree of relative crystallinity in frozen aqueous solutions. The requirement of operational setting is an appropriate degree of oscillation in combination with a number of modulations over a distinct transformation temperature. The selection of variables must produce a heating-cooling scan. (C) 1998 Elsevier Science B.V.

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Documento generato il 05/07/20 alle ore 00:50:28