Structure, mechanical properties and modelling of polypropylene for different degrees of crystallinity

Parenteau, Thomas; Ausias, Gilles; Grohens, Yves; Pilvin, Philippe

doi:10.1016/j.polymer.2012.09.053

Cited by 51 publications

(31 citation statements)

References 47 publications

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“…These results point out that crystalline phase undergo no modification in agreement with numerous studies. 13,18,22,27 Consequently, it seems that only amorphous phase undergoes deformation in cyclic regime considered in present work. On the other hand, regime change observed during our fatigue tests may be attributed to the relaxation mechanism of tie molecules, which represent the link between crystalline phase and free amorphous phase.…”

Section: Composite Modelmentioning

confidence: 77%

“…Our tests were carried out in the viscoelastic domain, so crystalline phase should not be deformed and in accordance with previous work the crystallinity does not evolve. 18 In order to verify this point, complimentary tests (DSC and X-ray diffraction) have been performed on our HDPE samples after fatigue tests to estimate possible modifications of crystallinity, lattice parameters, and the mean thickness of crystalline lamellae (L). DSC measurements highlight that melting temperature stay constant (around 130 C) which means, according to Gibbs-Thomson equation (a relation between the mean thickness of crystalline lamellae and melting temperature) that the thickness of crystalline lamellae stays constant during cyclic loading.…”

Section: Composite Modelmentioning

confidence: 98%

“…The scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) were used by some authors to follow the degree of crystallinity affected by possible chain arrangement and alignment 16 and modification of spherulite morphology. 17 It is also experimentally difficult to highlight these mechanisms for lower strain than pre-necking stage 18 and their consequences on internal stresses states. 8,12,18 Mechanical response is sensitive to the molecular structure and depends on factors such as crystallinity, chain entanglement, molecular weight, size of lamellae, and crosslink density.…”

mentioning

confidence: 99%

“…17 It is also experimentally difficult to highlight these mechanisms for lower strain than pre-necking stage 18 and their consequences on internal stresses states. 8,12,18 Mechanical response is sensitive to the molecular structure and depends on factors such as crystallinity, chain entanglement, molecular weight, size of lamellae, and crosslink density. [19][20][21] It is influenced by a number of mechanical factors including the stress or strain amplitude of the loading cycle, the mean stress of the cycle, and the presence of stress concentration or initial defects in the component.…”

mentioning

confidence: 99%

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Fluorescence spectroscopy applied to study cyclic creep behaviour and internal stresses of semi-crystalline high-density polyethylene

Bouvet

Douminge

Feaugas

et al. 2013

Journal of Applied Physics

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Cyclic creep or ratcheting behaviour has been characterized on semi-crystalline high-density polyethylene (HDPE) at 293 K using in situ extrinsic fluorescence spectroscopy. Fluorescent probe inserted in polymer offers the opportunity to establish a relationship between fluorescence phenomena and mechanical behaviour and more specifically to internal stresses. The influence of mean stress (σm), and stress amplitude (σa), on ratcheting strain (εr) and strain amplitude (εa) was studied in term of internal stresses development. The physical base of internal stress state has been discussed.

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Section: Composite Modelmentioning

confidence: 77%

Section: Composite Modelmentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Fluorescence spectroscopy applied to study cyclic creep behaviour and internal stresses of semi-crystalline high-density polyethylene

Bouvet

Douminge

Feaugas

et al. 2013

Journal of Applied Physics

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“…Both nano-mechanical models (Nikolov et al, 2002;van Dommelen et al, 2003;Seidel and Lagoudas, 2006;Bédoui et al, 2006;Parenteau et al, 2012) and phenomenological laws (Drozdov and Gupta, 2003;de Villoria and Miravete, 2007;Ganβ et al, 2008;Zrida et al, 2009) are suitable for the nanomicro homogenization step. Because the knowledge of the structural behavior at the nano-scale is still limited, phenomenological laws, validated via experimental results, are often preferred at this scale.…”

Section: Introductionmentioning

confidence: 99%

Experimental and computational micro-mechanical investigations of compressive properties of polypropylene/multi-walled carbon nanotubes nanocomposite foams

Wan¹,

Tran

Leblanc

et al. 2015

Mechanics of Materials

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The compressive behavior of nanocomposite foams is studied by both experimental and computational micro-mechanics approaches with the aim of providing an efficient computational model for this kind of material.The nanocomposites based on polypropylene (PP) and different contents of multi-walled carbon nanotubes (CNTs) method. The nanocomposite samples are foamed using super-critical carbon dioxide (ScCO 2 ) as blowing agent at different soaking temperatures. The influence of this foaming parameter on the morphological characteristics of the foam micro-structure is discussed. Differential Scanning Calorimetry (DSC) measurements are used to quantify the crystallinity degree of both nanocomposites and foams showing that the crystallinity degree is reduced after the foaming process. This modification leads to mechanical properties of the foam cell walls that are different from the raw nanocomposite PP/CNTs material. Three-point bending tests are performed on the latter to measure the flexural modulus in terms of the crystallinity degree. Uniaxial compression tests are then performed on the foamed samples under quasi-static conditions in order to extract the macro-scale compressive response. Next, a two-level multi-scale approach is developed to model the behavior of the foamed nanocomposite material. On the one hand, the micromechanical properties of nanocomposite PP/CNTs cell walls are evaluated from a theoretical homogenization model accounting for the micro-structure of the semi-crystalline PP, for the degree of crystallinity, and for the CNT volume fraction. The applicability of this theoretical model is demonstrated via the comparison with experimental data from the described experimental measurements and from literature. On the other hand, the macroscopic behavior of the foamed material is evaluated using a computational micromechanics model using tetrakaidecahedron unit cells and periodic boundary conditions to estimate the homogenized properties. The unit cell is combined with several geometrical imperfections in order to capture the elastic collapse of the foamed material. The numerical results are compared to the experimental measurements and it is shown that the proposed unit cell computational micro-mechanics model can be used to estimate the homogenized behavior, including the linear and plateau regimes, of nanocomposite foams.

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Efficiency of silver‐based antibacterial additives and its influence in thermoplastic elastomers

Tomacheski

Pittol

Ribeiro

et al. 2016

J of Applied Polymer Sci

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Styrene-butylene/ethylene-styrene-based thermoplastic elastomers (TPE) are polymers with soft touch properties that are widely used for manufacturing devices that involve hand contact. However, when contaminated with microorganisms these products can contribute to spreading diseases. The incorporation of antibacterial additives can help maintain low bacteria counts. This work evaluated the antibacterial action of TPE loaded with silver ions and silver nanoparticles. The additives nanosilver on fumed silica (NpAg_silica), silver phosphate glass (Ag 1 _phosphate), and bentonite organomodified with silver (Ag 1 _bentonite) were added to the TPE formulation. The compounds were evaluated for tensile and thermal properties and antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). All the additives eliminated over 90% of E. coli, but only NpAg_silica killed more than 80% of S. aureus population. The better effect of NpAg_silica was attributed to the additive's high specific surface area, which promoted greater contact with bacteria cells.

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Structure, mechanical properties and modelling of polypropylene for different degrees of crystallinity

Cited by 51 publications

References 47 publications

Fluorescence spectroscopy applied to study cyclic creep behaviour and internal stresses of semi-crystalline high-density polyethylene

Fluorescence spectroscopy applied to study cyclic creep behaviour and internal stresses of semi-crystalline high-density polyethylene

Experimental and computational micro-mechanical investigations of compressive properties of polypropylene/multi-walled carbon nanotubes nanocomposite foams

Efficiency of silver‐based antibacterial additives and its influence in thermoplastic elastomers

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