The changing anisotropy character of weathered low-density polyethylene films recognized by quasi-static and ultrasonic mechanical testing

Autor:	R. Huchon, M. Sebaa, B. De Jeso, S. F. Chabira
Rok vydání:	2006
Předmět:	Materials science Polymers and Plastics Film plane Mineralogy Polyethylene Condensed Matter Physics Viscoelasticity chemistry.chemical_compound Low-density polyethylene Crystallinity chemistry Mechanics of Materials Materials Chemistry Ultrasonic sensor Composite material Anisotropy Tensile testing
Zdroj:	Polymer Degradation and Stability. 91:1887-1895
ISSN:	0141-3910
Popis:	Unstabilised polyethylene films used for greenhouse covering have been exposed outdoors under the severe weathering conditions in the Sahara. The chemical and the morphological changes followed by infrared spectroscopy and by differential scanning calorimetry (DSC) show that the damages caused by oxidation to the tie molecules increase crystallinity and lead to a severe deterioration of the mechanical properties. The mechanical aspect of aging was studied by using standard quasi-static (QS) tensile testing measurements and by a non-destructive method based on ultrasound (US). This latter technique consists of measuring velocities and attenuations of ultrasonic waves propagating in several directions in the film plane. Both methods show the changing anisotropic character of the films with aging. The transverse direction has been found to be the principal axis of anisotropy consequently to a little more significant chain orientation in this direction acquired during processing. The connection between the chemical aspect of aging and the mechanical one (i.e. the viscoelastic properties and the anisotropic character) is discussed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8d8c10386d8afba256dec51a331f9efa https://doi.org/10.1016/j.polymdegradstab.2005.11.007 Zobrazit plný text záznamu Full Text from ScienceDirect