ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The effect of thermal history on the melting behavior of several linear polymer and copolymers of ethylene has been studied by using a Perkin-Elmer DSC-1 differential scanning calorimeter. Samples of film were heated above their melting point and then cooled at various rates in order to establish a known thermal history. During melting, homopolymers showed one peak and the copolymers two peaks in the DSC scan. The positions and relative sizes of the peaks were dependent on the prior cooling rate. It is suggested that two crystal types occur in the case of copolymers because of entanglements in the branched segments of the molecules. The position of the lower melting endotherm in blown films suggests that cooling rates of about 500°C./min. are achieved in this process.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1967.070111119
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