ISSN:
1042-7147
Keywords:
Orientation
;
Injection-molding
;
X-ray scattering
;
Polyethylene
;
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
Notes:
Highly oriented linear polyethylene was prepared by elongational flow injection molding. The changes in crystal orientation were investigated as a function of temperature by real-time wide-angle X-ray diffraction. Additionally, the influence of molecular weight upon the microstructure and the changes in orientation, during heating near the melting point, and after cooling have been examined. A shish-kebab structure is inferred for the high molecular weight samples (Mw≥105) from SAXS observations, while for samples with Mw〈105 only an oriented lamellar structure is found. Consequently, a higher thermal stability is shown by the higher molecular weight samples. Furthermore, a recovery of crystal orientation on rapid cooling of the samples from the melt is only observed for samples with Mw≥105. The results are discussed in terms of a preferential recrystallization of chain-folded lamellae, on cooling, onto the shish fibrils which survive at high temperature.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pat.1991.220020201
Permalink
