In situ observation of the plastic deformation of polypropylene spherulites under uniaxial tension and simple shear in the scanning electron microscope

Aboulfaraj, M.; G’Sell, C.; Ulrich, B.; Dahoun, Abdesselam

doi:10.1016/0032-3861(95)93102-r

Cited by 248 publications

(197 citation statements)

References 18 publications

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“…It is widely used in many different applications such as for appliances, packaging, textiles, reinforcing fibers, monofilaments, film, automotive parts, reusable containers of various types, and other durable items for home and garden uses. Additionally, the ranges of properties and applications for PP may extend in various ways by physical treatments, for example, thermal treatment [1][2][3] and plastic deformation [4,5]. PP can be also modified by adding fillers and/or blended with other polymers [6][7] and recently was used as a matrix polymer to blend with nanoparticles/carbon nanotubes to form nanocomposite materials [8,9], in which the main field of attention is the enhancement of mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

“…Such annealing also changes the morphological modification of crystal regions through lamellae thickening in the semi-crystalline polymers. The effect of annealing at macroscopic level is one of important factors to improve mechanical properties of the materials such as Young's modulus, impact strength, tensile strength, and toughness [1][2][3][4][38][39][40][41]. From above reasons, the effects of annealing of PP on its mechanical, impact and fracture properties, crystalline structure, phase transformation, crystallization behavior, elastic response as well as morphology have gained much attention in the last decade [1-3, 39, 40, 43-47].…”

Section: Introductionmentioning

confidence: 99%

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Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Saengsuwan

2008

E-Polymers

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Abstract:The influence of annealing on the microstructure and molecular orientation, thermal behaviour and mechanical properties of uniaxially drawn iPP thin film was studied by wide-angle X-ray diffraction, differential scanning calorimetry and tensile testing, respectively. The correlations of mechanical and microstructural properties of annealed films were also examined. The transformation of smectic phase of iPP to the α-form was more pronounced with increasing annealing time and temperature. The true and apparent crystallinities and crystal thickness were strongly enhanced with annealing time and temperature. The relative molecular orientation tended to increase with annealing time. These results caused the significant improvement of modulus and tensile strength of the annealed films in both machine (MD) and transverse (TD) directions. The increases in MD-Young's modulus and MD-tensile strength were well correlated with the increase in true crystallinity obtained in equatorial scans. Some relationship between the increase in crystal thickness and the increase in Young's modulus in both MD and TD directions was also found.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Saengsuwan

2008

E-Polymers

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“…By applying shear flow or adding special nucleating agents, the crystal form of iPP could be adjusted. Aboulfaraj et al [13] found that under tensile deformation, α-iPP spherulites exhibited a brittle failure. The cavitation appeared at boundaries of spherulites or at their equatorial regions perpendicular to the tensile direction.…”

Section: Role Of Crystal Formmentioning

confidence: 99%

Cavitation Behavior of Semi-Crystalline Polymers during Uniaxial Stretching Studied by Synchrotron Small-Angle X-Ray Scattering

Chang¹,

Schneider²,

Kuehnert³

et al. 2018

Small Angle Scattering and Diffraction

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Cavitation appears in many semi-crystalline polymers when they are subjected to uniaxial stretching above their glass transition temperatures. Generally, the formation of voids is influenced by the morphology of semi-crystalline polymers, including their lamellae thickness, lamellae orientation, as well as the arrangement of the amorphous phase. Upon stretching, the size of the voids changes as a function of the local strain. Synchrotron small-angle X-ray scattering (SAXS) can be used as a powerful method to in-situ monitor the evolution of voids with high time and spatial resolution. In this chapter, recent reports about the cavitation behavior of semi-crystalline polymers studied by SAXS are reviewed. Afterwards, the theoretical background related to the SAXS technique is introduced. Lastly, some exemplary results about the cavitation behavior of microinjection-molded isotactic-polypropylene, studied by synchrotron SAXS measurements, are presented.

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“…The resulting lattice parameters were cross-checked with the smaller peaks at 2θ > 27° to ensure that the deconvoluted lattice parameters are correct. , and K is a parameter correcting the signal intensity of the amorphous phase to the crystalline phase [39]. This was necessary because the density and thus the electron density (responsible for the scattering) of the crystalline phase is higher than the one of the amorphous phase, which leads to differences in the scattering intensities.…”

Section: Samplesmentioning

confidence: 99%

Lattice sizes, crystallinities, and spacing between amorphous chains - characterization of ethene-/ɑ-olefin copolymers with various comonomers and comonomer contents measured by wide angle X-ray scattering

Stadler¹,

Takahashi

Yonetake

2009

E-Polymers

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Ethene-/-olefin copolymers having a wide range of comonomer contents with comonomers between 4 and 26 carbon atoms in length were characterized by wide angle X-ray scattering (WAXS). It was found that the crystallinities matched fairly well with the crystallinities from DSC and volumetric measurements. An increase of the crystal lattice size was found with increasing comonomer content and comonomer length. Both are attributed to the formation of defects around these short-chain branches in the crystal lattice, which widen it. Increasing the cooling time will lead to a more densely packed crystal structure, if the quenched structure is distorted, i.e. if the sample contains comonomer. A higher molar mass M w widens the average space between chains in the amorphous phase as well as the addition of comonomer. The latter finding is explained by the increasing number of chain ends introduced by the comonomer which increases the free volume in the sample because of the worse amorphous packing of the chain ends.

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In situ observation of the plastic deformation of polypropylene spherulites under uniaxial tension and simple shear in the scanning electron microscope

Cited by 248 publications

References 18 publications

Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Influence of annealing on microstructure & molecular orientation, thermal behaviour, mechanical properties and their correlations of uniaxially drawn iPP thin film

Cavitation Behavior of Semi-Crystalline Polymers during Uniaxial Stretching Studied by Synchrotron Small-Angle X-Ray Scattering

Lattice sizes, crystallinities, and spacing between amorphous chains - characterization of ethene-/ɑ-olefin copolymers with various comonomers and comonomer contents measured by wide angle X-ray scattering

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