Modeling the visco-hyperelastic-viscoplastic behavior of photodegraded semi-crystalline low-density polyethylene films

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:204

Article

Ayoub, G.¹  Rodriguez, A. K.^2,3  Mansoor, B.^2,3  Colin, X.⁴ 

[1] Univ Michigan, Dept Ind & Mfg Syst Engn, Dearborn, MI 48128 USA

[2] Texas A&M Univ, Dept Mat Sci & Engn, College Stn, TX 77843 USA

[3] Texas A&M Univ Qatar, Dept Mech Engn, Doha 28874, Qatar

[4] PIMM, Arts & Metiers Inst Technol, 151 Blvd Hop, F-75013 Paris, France

关键词: Polymeric material;    Photo-degradation;    Visco-hyperelastic-viscoplastic modeling;    Chain scissions;    Chemi-crystallization;   

DOI  :  10.1016/j.ijsolstr.2020.08.025

来源: Elsevier

【 摘 要 】

In this work we propose to model the mechanical and fracture response of semi-crystalline low-density polyethylene (LDPE) films exposed to accelerated ultraviolet (UV) ageing using a physically based visco-hemical and structural properties of the semi-crystalline polymer, which affects significantly its mechanical behavior. In this work, pristine and oxidized low-density polyethylene films are characterized by conventional physico-chemical and mechanical techniques (FTIR spectroscopy, DSC, HT-GPC, and uniaxial tensile testing). Polyethylene exhibits an oxidation-induced strengthening for a low range of UV radiation doses and a cavitation-induced softening for higher UV radiation doses. A competing multi-scale phenomena induced by UV radiation are incorporated into the constitutive model to capture the macroscopically observed mechanical and fracture behavior. Namely, the model will incorporate at the nano scale, chain scissions and cross-linking and at the meso and macro scales, oxidation-induced cracking, chemi-crystallization, and mechanical damage. The model used the high-temperature gel permeation chromatography-measured molecular weight as degradation indicator. The model was able to capture accurately the evolution of the macroscopically observed mechanical and fracture behavior over a wide range of UV irradiation doses. (C) 2020 Elsevier Ltd. All rights reserved.

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