ISSN:
0887-6266
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The question as to whether fractionation occurs during the crystallization of homopolymers from the pure melt has been addressed by studying linear polyethylene mixtures. Two methods were used. In one procedure, mixtures of well-defined fractions were crystallized under controlled conditions and the subsequent fusion process was analyzed. In the other procedure, a selective extraction was carried out on an isothermally crystallized polydisperse whole polymer, and the residue was analyzed by gel permeation chromatography. Both methods lead to the same conclusion, namely that during isothermal crystallization only the very low molecular weight species crystallize separately. An extreme upper limit to fractionation corresponds to M = 7000. More likely, fractionation in linear polyethylene during bulk crystallization is restricted to molecular weights of 5000 or less.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1988.090260201
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