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Water plasticization frozen systems

A comparison of literature values of subzero collapse transition temperatures (Tc) for an extensive list of water-compatible monomers and polymers has established the fundamental identity of Tg with the minimum onset temperatures observed for various structural collapse and recrystallization processes (1.2.115), for both model solutions and real systems of foods, as well as pharmaceuticals and biologicals (38.42.106.108.109). The Tc and Tr values of frozen or vitrified samples, tabulated elsewhere (1.2.22). are typically determined by cryomicroscopy, thermal analysis, or electrical resistance measurements (22 and refs, therein), on an experimental time scale similar to that for Tg by our DSC method (106.109). A comprehensive list of collapse processes (Table I), all of which are governed by Tg of frozen systems (or a higher Tg pertaining to low moisture systems processed or stored at T > 0 C) and involve potentially detrimental plasticization by water, has been identified and elucidated (1-5.18-... [Pg.248]

Superabsorbent polymers are used as a liquid-absorber in food packaging systems. In these systems, the superabsorbent polymers absorb juice or water from fresh foods such as raw chicken, shellfish, and other meats or from frozen foods as they thaw. Chilled superabsorbent polymer gels may also be used as a dry-cooling medium. The water-swollen gel, contained in a durable plastic bag, is frozen and used to keep perishable foods cold. In addition to its liquid-water-absorption characteristic, superabsorbent polymers absorb water from the vapor state and therefore may be used to control humidity. [Pg.2892]


See other pages where Water plasticization frozen systems is mentioned: [Pg.316]    [Pg.512]    [Pg.252]    [Pg.71]    [Pg.201]    [Pg.470]    [Pg.9]    [Pg.401]    [Pg.311]    [Pg.72]    [Pg.895]    [Pg.180]    [Pg.250]    [Pg.323]   
See also in sourсe #XX -- [ Pg.75 ]




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Frozen systems

Plasticized systems

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