Hemoglobin polymer stability

1988 ◽  
Vol 22 (1) ◽  
pp. 69-72
Author(s):  
E. P. Vyazova ◽  
L. V. Fetisova ◽  
M. A. Azhigirova ◽  
A. A. Khachatur'yan
Keyword(s):  
Polymer Stability

scholarly journals Characterization of Food Packaging Films with Blackcurrant Fruit Waste as a Source of Antioxidant and Color Sensing Intelligent Material

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2569
Author(s):  
Mia Kurek ◽  
Nasreddine Benbettaieb ◽  
Mario Ščetar ◽  
Eliot Chaudy ◽  
Maja Repajić ◽  
...  
Keyword(s):  
Food Packaging ◽  
Water Solubility ◽  
Color Change ◽  
Chitosan Film ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Color Changes ◽  
Insoluble Particles ◽  
Polymer Stability ◽  
Food Packaging Films

Chitosan and pectin films were enriched with blackcurrant pomace powder (10 and 20% (w/w)), as bio-based material, to minimize food production losses and to increase the functional properties of produced films aimed at food coatings and wrappers. Water vapor permeability of active films increased up to 25%, moisture content for 27% in pectin-based ones, but water solubility was not significantly modified. Mechanical properties (tensile strength, elongation at break and Young’s modulus) were mainly decreased due to the residual insoluble particles present in blackcurrant waste. FTIR analysis showed no significant changes between the film samples. The degradation temperatures, determined by DSC, were reduced by 18 °C for chitosan-based samples and of 32 °C lower for the pectin-based samples with blackcurrant powder, indicating a disturbance in polymer stability. The antioxidant activity of active films was increased up to 30-fold. Lightness and redness of dry films significantly changed depending on the polymer type. Significant color changes, especially in chitosan film formulations, were observed after exposure to different pH buffers. This effect is further explored in formulations that were used as color change indicators for intelligent biopackaging.

Principles of polymer stability

1965 ◽  
Vol 5 (3) ◽  
pp. 204-207 ◽  
Author(s):  
Herman F. Mark ◽  
Sheldon H. Atlas
Keyword(s):  
Polymer Stability

Improvement of the polymer stability by radiation grafting

2004 ◽  
Vol 71 (1-2) ◽  
pp. 229-233 ◽  
Author(s):  
F Ranogajec ◽  
M Mlinac-Mišak
Keyword(s):  
Radiation Grafting ◽  
Polymer Stability

The use of heavy ions for the evaluation of the polymer stability

1974 ◽  
Vol 25 (7) ◽  
pp. 307-308 ◽  
Author(s):  
Ernesto Casnati ◽  
M. Marchetti ◽  
L. Tommasino
Keyword(s):  
Heavy Ions ◽  
Polymer Stability

The Reactions of Isocyanates and Isocyanate Derivatives at Elevated Temperatures

1959 ◽  
Vol 32 (2) ◽  
pp. 337-345 ◽  
Author(s):  
J. H. Saunders
Keyword(s):  
Elevated Temperatures ◽  
Temperature Stability ◽  
Hydroxyl Groups ◽  
Final State ◽  
Excellent Thermal Stability ◽  
Decomposition Reactions ◽  
Quantitative Studies ◽  
Polymer Stability ◽  
Reactive Groups ◽  
Selection Of

Abstract Qualitative and quantitative studies with model compounds have shown that a variety of reactions may occur at 100–300° in molecules containing isocyanate, urea and urethane groups. All or most of these reactions are subject to catalysis so that they may be induced to proceed at lower temperatures. These reactions are quite important as they may affect the production and practical use of polyurethanes and polyureas. By the proper selection of reaction components one may design a polyurethane or polyurea molecule which will give both a reasonable rate of cure to the final state and a degree of temperature stability suitable for many rigorous applications. The choice of reactive groups providing approximately the desired rates of reaction and of suitable catalysts may be used to achieve the necessary curing rate. The initial choice of a catalyst which will have a minimum effect on decomposition reactions, or the removal of the catalyst from the cured polymer will favor polymer stability. A selection of reactants which will minimize those decomposition reactions leading to chain rupture, and which will compensate for what rupture may occur, will promote polymer stability. Simple illustrations of such choices would include eliminating tertiary aliphatic hydroxyl groups from the hydroxyl-bearing component and including some degree of branching commensurate with the degree of elasticity or rigidity desired. Branching should be achieved through the more stable groups, e.g., urethane, urea or trimer, rather than through the less stable allophanate and biuret groups. Many thoroughly tested applications of polyurethanes and mixed polyureaurethanes show that it is readily possible to produce such polymers with excellent thermal stability.

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