Plastic deformation of low-density polyethylene reinforced with biodegradable polylactide, Part 2: Creep characterization and modeling

The behavior of low‐density polyethylene (LDPE) and two blends prepared with polylactide (PLA) was determined by means of a novel video‐controlled testing method under stretching at constant true strain rate, under creep at constant true stress, and under creep at constant nominal stress. Most tests...

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Bibliographic Details
Published in:Polymer engineering and science 2011-01, Vol.51 (1), p.126-132
Main Authors: Rezgui, F., G'Sell, C., Dahoun, A., Hiver, J.M., Sadoun, T.
Format: Article
Language:English
Subjects:
Analysis
Applied sciences
Axial stress
Biodegradation
Creep
Creep (materials)
Creep rupture strength
Deformations (Mechanics)
Exact sciences and technology
Low density polyethylenes
Materials
Mathematical models
Microstructure
Organic polymers
Physicochemistry of polymers
Plastic deformation
Plastics
Polyethylenes
Polylactides
Polymer blends
Properties and characterization
Rheology and viscoelasticity
Strain rate
Stretching
True strain
Yield stress
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Summary:The behavior of low‐density polyethylene (LDPE) and two blends prepared with polylactide (PLA) was determined by means of a novel video‐controlled testing method under stretching at constant true strain rate, under creep at constant true stress, and under creep at constant nominal stress. Most tests were performed at 23°C and 50°C. In this second part, the experimental data are modeled with the G'Sell‐Jonas phenomenological law expressing the axial true stress versus axial true strain and axial true strain rate. This model describes correctly the various deformation stages: (i) initial viscoelasticity, (ii) plastic yielding, and (iii) strain hardening up to rupture. It shows clearly the reinforcing effect of the PLA particles that increases the yield stress in stretching experiments and slows down the deformation kinetics under creep. It is shown how the local stress/strain behavior is related to the standard force/extension curves. Consequently, it is proposed that tensile tests at constant true strain rates should be systematically preferred to creep tests for the characterization of constitutive relations because they take much less time to be performed. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers.
ISSN:0032-3888
1548-2634
DOI:10.1002/pen.21796