ISSN:
1435-1536
Keywords:
Key words Gelatin
;
crosslinking
;
drawing
;
oriented films
;
dynamic mechanical properties
;
glass transition
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract This second part of a systematic study of the properties of crosslinked-oriented gelatin involves the effects of orientation and water content on the glass transition temperature T g and on the melting behavior. The samples were the same as those in the preceding study, and their transition temperatures were determined by both differential scanning calorimetry and dynamic mechanical thermal analysis. The crosslinked gelatin which had been room-conditioned showed two transition temperatures: the lower one was attributed to T g of the water-plasticized gelatin, and the higher one was interpreted as T g of dried gelatin superimposed by melting. A rather unusual situation arose because of the fact that the T g and melting temperatures T m (217 and 230 °C, respectively) are so similar. Using water as plasticizer not only decreases T g but produces imperfect crystallites which melt below the T g of the system. The presence of the amorphous phase in the glassy state would presumably make it essentially impossible to define a melting point or crystallization temperature in the normal manner, as an equilibrium between crystalline and amorphous phases.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003960050087
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