A general scheme derived from video-controlled stretching tests and WAXS for describing tensile deformations of polyethylenes

Hiss, R.; Hobeika, S.; Lynn, C.; Strobl, G.

doi:10.1080/00222349908248143

Cited by 7 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A widely accepted concept is that deformation of PE is initially dominated by the amorphous phase, due to its relatively low resistance to deformation [7]. The crystalline phase is involved at this stage through inter-lamellar shear, inter-lamellar separation, and lamellar stack rotation [7,8,9,10], of which the contribution depends on the loading mode and the stress level. In an engineering stress-stroke curve from tensile loading, PE is known to yield at the peak point, at which the lamellar structure starts to disintegrate.…”

Section: Introductionmentioning

confidence: 99%

Determining Deformation Transition in Polyethylene under Tensile Loading

Tan

Jar

2019

Polymers

View full text Add to dashboard Cite

The multi-relaxation (MR) test was developed based on the concept that stress relaxation behavior can be used to reflect the material state of polyethylene (PE) under tension. On the basis of this concept, critical stroke for the onset of plastic deformation in the crystalline phase, named the first critical stroke, was determined using the MR test. Results from wide angle X-ray scattering suggest that phase transformation occurred in the crystalline phase of PE after the specimen was stretched beyond the first critical stroke. In this work, the MR test was applied to six PEs of different mass densities to determine their first critical strokes and the corresponding total and quasi-static (QS) stress values. The results show that the first critical stroke had very similar values among the six PEs. More interestingly, the ratio of the QS stress at the first critical stroke to the yield stress from the standard tensile test showed little dependence on PE density. Therefore, it was possible to use the popular short-term tensile test to characterize the critical QS component of the applied stress to initiate plastic deformation in the crystalline phase, which is expected to play a significant role on the long-term, load-carrying applications of PE.

show abstract

Section: Introductionmentioning

confidence: 99%

Determining Deformation Transition in Polyethylene under Tensile Loading

Tan

Jar

2019

Polymers

View full text Add to dashboard Cite

show abstract

“…This suggests that the mid-to-late-stage pre-yield behaviour of WL specimens differs from that of REF specimens in the 30-CC formulations. In the deformation mechanism proposed by the Strobl group [ 16 , 17 , 18 , 19 , 20 , 21 ], this would suggest that nucleated/localised inter- and intralamellar slip stage has seen some type of change. Further evidence of complex interactions can be seen in Figure 9 , through the changes in curvature as a function of CB loading across the range of CC loadings.…”

Section: Results and Discussionmentioning

confidence: 99%

“…The localised deformation of a REF specimen without CC commences at—or very close to—the yield point. In unfilled semi-crystalline polymers, specifically HDPE and other polyolefins [ 16 , 17 , 18 , 19 , 20 , 21 , 26 ], this is known to be the point where collective inter- and intralamellar slip sets in. Curiously, no new peak formation occurs at the yield points of the WL specimens of the same type.…”

Section: Results and Discussionmentioning

confidence: 99%

“…Over the years, many have worked to develop a mechanistic understanding of the way in which semi-crystalline polymers—here with the focus on HDPE—are deformed under uniaxial load. Great progress was made by the Strobl group [ 16 , 17 , 18 , 19 , 20 , 21 ] building on the works of Bowden and coworkers [ 22 , 23 ], Fotheringham and Cherry [ 24 ], and Lohse and Gaylord [ 25 ], among many others. Further progress has been made in recent times, notably by Farge and coworkers on the fibrillation/cavitation process and its effects [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…Further progress has been made in recent times, notably by Farge and coworkers on the fibrillation/cavitation process and its effects [ 26 ]. The established mechanism may be summarised as (chronologically) [ 16 , 17 , 18 , 19 , 20 , 21 , 25 , 26 ]: The elongation and orientation of the amorphous regions between the lamellae; The onset of nucleated inter- and intralamellar slips; The collective inter- and intralamellar slips; The onset of fibrillation; and The onset of chain disentanglement. …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Tensile Behaviour of Highly Filled High-Density Polyethylene Quaternary Composites: Weld-Line Effects, DIC Curiosities and Shifted Deformation Mechanisms

et al. 2021

View full text Add to dashboard Cite

The interactive effects between additives and weld lines, which are frequent injection-moulding defects, were studied in high-density polyethylene (HDPE) and compared to weld-line-free reference samples. These materials were formulated around a D- and I-optimal experimental design, based on a quadratic Scheffé polynomial model, with up to 60 wt% calcium carbonate, masterbatched carbon black and a stabiliser package. Where reasonable and appropriate, the behaviours of the systems were modelled using statistical techniques, for a better understanding of the underlying trends. The characterisations were performed through the use of conventional tensile testing, digital image correlation (DIC) and scanning electron microscopy (SEM). A range of complex interactive effects were found during conventional tensile testing, with DIC used to better understand and explain these effects. SEM is used to better understand the failure mechanics of some of these systems through fractography, particularly regarding particle effects. A measure is introduced to quantify the deviation of the pre-yield deformation curve from the ideal elastic case. Novel analysis of DIC results is proposed, through the use of combined time-series plots and measures quantifying the extent and localisation of peak deformation. Through this, it could be found that strong shifts in the deformation mechanisms occur as a function of formulation and the presence/absence of weld lines. Primarily, changes are noted in the onset of continuous inter- and intralamellar slip and cavitation/fibrillation, seen through the onset of localised deformation and stress-whitening.

show abstract

Deformation Mechanisms of Semi-Crystalline Polymers on the Submicron Scale

Michler

Godehardt

2000

Cryst. Res. Technol.

View full text Add to dashboard Cite

Micromechanical deformation mechanisms of two slightly branched polyethylenes have been studied by transmission electron microscopy and scanning force microscopy. Using an ethylene/hexene copolymer the transformation of the lamellar structure in the oriented structure inside a notch‐tip craze and using a binary blend of different ethylene/1‐hexene copolymers the deformation at elastomeric particles were investigated in detail. In particular, the micro‐block arrangement in lamellae and the transformation in structures like strings of beads have been studied using microscopy at higher magnifications.

show abstract

A general scheme derived from video-controlled stretching tests and WAXS for describing tensile deformations of polyethylenes

Cited by 7 publications

References 10 publications

Determining Deformation Transition in Polyethylene under Tensile Loading

Determining Deformation Transition in Polyethylene under Tensile Loading

The Tensile Behaviour of Highly Filled High-Density Polyethylene Quaternary Composites: Weld-Line Effects, DIC Curiosities and Shifted Deformation Mechanisms

Deformation Mechanisms of Semi-Crystalline Polymers on the Submicron Scale

Contact Info

Product

Resources

About