ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Studies of the kinetics of crystallization were performed on polyethylene-naphthalene-2,6-dicarboxylate (PEN) and onits copolyester with p-hydroxybenzoic acid (PHB). It is shown that PEN crystallizes in two different crystal modifications. The copolyester forms a lattice which corresponds to one of the two crystal modifications of PEN. At 230 °C the copolyester goes over into the liquid crystalline state. The orientation of the chains in small regionsoccurring in this state does not increase considerably the rate of crystallization after cooling. In the liquid crystalline state fluctuations of the chain orientation in regions of about 2 mm × 2 mm are observed with a characteristic time constant of about 3 min. In addition, the change of small angle X-ray scattering during melting and recrystallization of poly(ethylene terephthalate) is investigated. The change of scattering power and of the shape of the scattering curve was observed as a function of temperature and time. At low temperatures, with increasing temperature, the position of the scattering peak shifted gradually and irreversibly to smaller angles. At 245°C the small angle scattering first disappeared completely and appeared later again, the peak lying at smaller angles. The results depend strongly on the heating rate.
Additional Material:
21 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1985.020121985116
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