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Study of cryostructuration of polymer systems. XVI. Freeze–thaw‐induced effects in the low concentration systems amylopectin–water
Author(s) -
Lozinsky Vladimir I.,
Damshkaln Lilija G.,
Brown Rupert,
Norton Ian T.
Publication year - 2000
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(20000401)75:14<1740::aid-app8>3.0.co;2-1
Subject(s) - amylopectin , enthalpy , polymer , chemistry , precipitation , starch , polysaccharide , chemical engineering , polymer chemistry , thermodynamics , organic chemistry , amylose , engineering , physics , meteorology
Studies of the freeze–thaw behavior of low‐concentrated (0.01–0.25 g/dL) water solutions and dilute pastes (0.5–1.0 g/dL) of maize starch amylopectin showed that cryogenic treatment of these systems resulted in the formation of precipitated matter, whose yield and thermal characteristics (melting temperature and enthalpy) depended on the initial polymer concentration and conditions of freezing, frozen storage, and thawing. Research of the kinetic features of these cryoprecipitation events revealed at least two stages for this process: (i) a rapid stage, when the precipitation of virtually all of the dissolved polysaccharide occurred while the system was freezing, and (ii) a slower stage, the rate of which was mainly dependent on the thawing regimes or duration of the sample storage frozen at subzero temperatures. Cryoprecipitation phenomena were observed to be most extensive at temperatures 1–2° below the melting point of the frozen system. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1740–1748, 2000