Morphology of undeformed and deformed polyethylene lamellar crystals

0349870 - ÚMCH 2011 RIV GB eng J - Journal Article
Galeski, A. - Bartczak, Z. - Kazmierczak, T. - Šlouf, Miroslav
Morphology of undeformed and deformed polyethylene lamellar crystals.
Polymer. Roč. 51, č. 24 (2010), s. 5780-5787. ISSN 0032-3861. E-ISSN 1873-2291
R&D Projects: GA ČR GAP205/10/0348
Institutional research plan: CEZ:AV0Z40500505
Keywords : polyethylene * lamellae * plastic deformation
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.829, year: 2010

Morphology of undeformed polyethylene crystals obtained by high pressure crystallization was investigated by SEM. The etching procedure was refined to reveal defected sites of lamellae in addition to differentiation of crystalline and amorphous phases. From 1 to 3 screw dislocations with large Burgers vector per 1 μm2 of lamellae basal planes were detected. High pressure-crystallized polyethylene samples were deformed plastically by uniaxial compression and studied by SEM and AFM. When the deformation is interrupted dislocations are arrested within the crystals. Plastically deformed polyethylene crystals are highly defected – the density of dislocations was approximated as 1016 m−2. However, deformed crystal melting temperature is nearly unaffected while the heat of melting is slightly reduced, yet only in thin crystals. It suggests that the arrested dislocations contribute more to the surface energy of lamellae basal planes rather than to the bulk energy of polyethylene crystals.
Permanent Link: http://hdl.handle.net/11104/0006116