Macroscopically homogeneous deformation in injection molded polypropylene induced by annealing studied with microbeam X-ray scattering

Matsui, Kazuya; Bando, Akinori; Sakurai, Takashi; Shinohara, Yuya; Maruyama, Toshiya; Masunaga, Hiroyasu; Amemiya, Yoshiyuki

doi:10.1016/j.polymer.2015.06.039

Cited by 9 publications

(7 citation statements)

References 53 publications

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“…Consequently, it is difficult to distinguish the cavitation triggered at large strain from those cavities generated in the system at small strains. Efficient methods to avoid small strain cavitation process could be increasing the stretching temperature and decreasing the lamellar thickness of polymers based on the results mentioned above. In addition, a solid‐state processing method of die drawing process developed by Ward et al., described as confined stretching, makes it possible to draw materials at high temperatures .…”

Section: Macroscopic Phenomena Of Cavitation‐induced Stress Whiteningmentioning

confidence: 99%

“…The testing environment acts as another parameter determining the mechanical behaviors of polymers as well. Polyolefin born as semi‐crystallizing polymers, such as isotactic polypropylene (iPP), polyethylene (PE), and polybutene‐1 (PB‐1) are phenomenally utilized as commercial products, for example, pipe, packaging, and electric appliance in our daily life. To understand the crystallization behaviors and mechanical properties of polymers under different processing conditions are drastically attracting attentions from both industry and academia.…”

Section: Introductionmentioning

confidence: 99%

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Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

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Cavitation‐induced stress whitening in semi‐crystalline polymers during stretching significantly influences the physical properties of the materials. This review summarizes studies focusing on two different cavitation processes triggered at small and large strain regimes. The corresponding mechanisms of these two cavitation processes are discussed. For cavitation activated at small strain, there are two basic but distinctly different models with the initiation of cavities either in the amorphous phase or in the crystalline skeleton. For the cavitation triggered at a large strain regime, there are also two different arguments being either due to the defects located in the ends of micro‐fibrils or as a consequence of the fragmentation of load‐bearing inter‐fibril/micro‐fibril tie chains in highly oriented amorphous networks. A unified understanding of the cavitation processes during stretching semi‐crystalline polymers based on interpenetrated network model is proposed. Finally, this review outlooks future research topics for better understanding the cavitation mechanism to meet the industrial need.

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Section: Macroscopic Phenomena Of Cavitation‐induced Stress Whiteningmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Men

2018

Macro Materials & Eng

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“…For wide angle X-ray diffraction, the degree of crystalline ordering, including the packing order and crystal size, can be estimated from the full width at half maximum (FWHM) of a diffraction peak by using the Scherrer's formula, and the narrower FWHM implicates the larger crystalline ordering [41]. It is therefore reasonable that the FWHM of a scattering peak of SAXS patterns can also be employed to evaluate the degree of ordering, especially the size distribution of periodic structures.…”

Section: Resultsmentioning

confidence: 99%

“…open sci. 6: 181866 using the Scherrer's formula, and the narrower FWHM implicates the larger crystalline ordering [41]. It is therefore reasonable that the FWHM of a scattering peak of SAXS patterns can also be employed to evaluate the degree of ordering, especially the size distribution of periodic structures.…”

Section: Resultsmentioning

confidence: 99%

Microbeam two-dimensional small-angle X-ray scattering investigating the effects of reduced graphene oxide on local microstructures of high-density polyethylene/reduced graphene oxide nanocomposite bars

et al. 2019

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It has been reported that the introduction of reduced graphene oxide (RGO) can enhance the crystallization and orientation of high-density polyethylene (HDPE) matrix and thus improve the mechanical properties of HDPE/RGO nanocomposites. In this study, the local microstructures and orientations in different regions of HDPE/RGO bars with varied RGO contents were further explored by two-dimensional small-angle X-ray scattering using a microbeam technique. It is unveiled that the orientation orderings of each position is intensified with increasing RGO amount, and of particular interest is the observation of the slight change of the ordering degrees in diverse zones of HDPE/RGO nanocomposite bars, indicating that RGO imposes a uniform enhancing effect upon HDPE matrix within different areas and consequently induces an effective increase of the mechanical properties of HDPE/RGO nanocomposites.

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“…12 However, the yield strength of iPPBu decreases with lamella thickness due to the higher content of the butene comonomer unit incorporated in the crystalline region. 12 As typical semicrystalline polymers applied in industry and in everyday life, [17][18][19][20][21][22][23] iPP homopolymer and iPP-⊍-olefin copolymers exhibit polymorphic behavior and can crystallize in monoclinic ⊍, trigonal ⊎ and orthorhombic γ forms, and in a new trigonal form under different crystallization conditions. [24][25][26][27][28][29][30][31] Moreover, a mesomorphic form, 32 whose degree of ordering is intermediate between that of the crystalline phase and the amorphous phase, can be obtained via rapidly cooling from melt to temperature above the glass transition temperature or by annealing completely amorphous iPP.…”

Section: Introductionmentioning

confidence: 99%

Structural evolution of mesomorphic propylene–1‐butene random copolymer during heating process

Qian

Zhao

Wang

2021

Polymer International

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The study of the transition of mesophase to ⊍-crystal (meso-⊍ transition) is of great significance for understanding the crystallization, morphology as well as processability of polypropylene materials. The structural evolution of mesomorphic isotactic propylene-1-butene (iPPBu) random copolymer during the continuous heating process was investigated using in situ Fourier transform infrared spectroscopy, differential scanning calorimetry, wide-angle X-ray diffraction and dynamic mechanical analysis. The presence of the butene comonomer influences the meso-⊍ transition behavior. Compared with the mesomorphic iPP homopolymer, the presence of butene comonomer reduces both onset temperature (T onset ) and end temperature (T end ) of the meso-⊍ transition, and narrows the transition temperature range. The content of the 3 1 helical sequence with 12 monomers remains invariant during the meso-⊍ transition, differing from that of mesomorphic iPP homopolymer. Similar to mesomorphic iPP homopolymer, the 3 1 helical sequence with monomer number n ≤ 12 is found to exist in the rigid amorphous fraction of iPPBu, but is different from that of a mesomorphic propylene-ethylene random copolymer. In the meso-⊍ transition (from 60 to 100 °C), the redshift of the peak position of the band at ca 841 cm −1 provides new information for the approaching of adjacent stems at the molecular level. Moreover, a new peak at around T end is found in the tan(⊐)-T plot, and is correlated with the meso-⊍ transition. The activation energy of the meso-⊍ transition of mesomorphic iPPBu is 32.5 kJ mol −1 , which is slightly lower than that of mesomorphic iPP homopolymer. This work sheds new light on further understanding of the meso-⊍ transition mechanism of iPPBu copolymer at the molecular level and elucidates the effect of butene comonomer on the meso-⊍ transition.

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Macroscopically homogeneous deformation in injection molded polypropylene induced by annealing studied with microbeam X-ray scattering

Cited by 9 publications

References 53 publications

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Cavitation‐Induced Stress Whitening in Semi‐Crystalline Polymers

Microbeam two-dimensional small-angle X-ray scattering investigating the effects of reduced graphene oxide on local microstructures of high-density polyethylene/reduced graphene oxide nanocomposite bars

Structural evolution of mesomorphic propylene–1‐butene random copolymer during heating process

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