Temperature dependency of cavitation in impact copolymer polypropylene during stretching

Li, Qian; Zhang, Yue; Zhao, Xintong; Xiang, Mingyue; Lu, Ying; Men, Yongfeng

doi:10.1016/j.polymer.2021.123428

Cited by 12 publications

(11 citation statements)

References 55 publications

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“…They found that the intensity of the void scattering increased with the increasing temperature during stretching. They suggested that it is due to the melting of cEPs located at the core and shell of the EPR droplet that promotes the void nucleation . This is relevant to our results at 130 °C (above the melting point of cEP), where the stress–strain curves of the IPCs became comparable to that of hPP.…”

Section: Resultssupporting

confidence: 80%

“…They suggested that it is due to the melting of cEPs located at the core and shell of the EPR droplet that promotes the void nucleation. 54 This is relevant to our results at 130 °C (above the melting point of cEP), where the stress−strain curves of the IPCs became comparable to that of hPP. However, at 40 °C, the IPC samples were found to be able to elongate 20−30 times longer than hPP.…”

Section: ■ Results and Discussionsupporting

confidence: 64%

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Time-Resolved SAXS/WAXD under Tensile Deformation: Role of Segmental Ethylene–Propylene Copolymers in Impact-Resistant Polypropylene Copolymers

Rungswang

Jarumaneeroj

Jirasukho

et al. 2021

ACS Appl. Polym. Mater.

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Structural evolution of impact-resistant polypropylene copolymers (IPCs), having different compositions of segmental ethylene−propylene (sEP) copolymers, under tensile deformation was investigated by time-resolved small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) at elevated temperatures. At 40 °C, IPCs with a higher P content in sEP copolymers showed much longer elongation at break ratios than IPCs with a lower P content, which suggested the role of interfacial adhesion between the ethylene−propylene random (EPR) copolymer and homo polypropylene (hPP) phases. Polarized optical microscopy revealed the existence of the interfacial crystallite grown from the hPP spherulitic interface into the EPR phase. This indicated that the P segment might have promoted the interfacial adhesion between the EPR/hPP phases. To further verify this hypothesis, tensile experiments were carried out at 130 °C, a temperature higher than the melting temperature of the copolymer crystal. As expected, the tensile property of the IPCs became comparable with that of hPP, which also confirmed the role of the interfacial crystallite. SAXS and WAXD results revealed that for IPCs with higher interfacial adhesion, the crystal fracture was delayed at the strain near the yield point. However, its fibrillation process became faster than that of IPCs with poorer interfacial adhesion. The nano-and micro-void formation was investigated through SAXS and X-ray tomography techniques, respectively. Interestingly, both nano-and micro-voids, which first elongated along the transverse direction and then sequentially reoriented along the stretching direction, were observed for the first time, and it was termed the "double cavitation" process. The results indicated that the nano-and micro-voids of IPCs with high interfacial adhesion were smaller than those of hPP. This study shows the role of interfacial adhesion in sEP copolymers in improving the failure resistance during tensile deformation.

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Section: Resultssupporting

confidence: 80%

Section: ■ Results and Discussionsupporting

confidence: 64%

Time-Resolved SAXS/WAXD under Tensile Deformation: Role of Segmental Ethylene–Propylene Copolymers in Impact-Resistant Polypropylene Copolymers

Rungswang

Jarumaneeroj

Jirasukho

et al. 2021

ACS Appl. Polym. Mater.

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“…The void formation in semicrystalline polymer upon stretching was reported widely in PP, 29,33,60 PE, 61 poly(1‐butene), 56 P4MP1, 28 polyamide 6, 62 and so on. The void formation will be influenced by either the sample intrinsic characters like crystallinity, crystal form, lamellae orientation and morphology, and mobility of polymer chains in the amorphous phase, or the stretching temperature and stretching speed.…”

Section: Resultsmentioning

confidence: 96%

Influence of crystal orientation on stretching induced void formation in poly(4‐methyl‐1‐pentene) investigated by in‐situ small‐angle and wide‐angle X‐ ray scattering

Yang

Liu

Shi

et al. 2021

Polymer Crystallization

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“…The dependence of morphology evolution on draw temperature was analyzed, resulting in other deformation mechanisms with varying draw temperatures. [ 29,86,185 ]…”

Section: The Evolution Of Microstructure and Characterization Of A Si...mentioning

confidence: 99%

“…The dependence of morphology evolution on draw temperature was analyzed, resulting in other deformation mechanisms with varying draw temperatures. [29,86,185] A schematic illustration of the deformation mechanism during uniaxial stretching at different temperatures is shown in Figure 22. At low draw temperature (25 °C), both the degree of crystallinity and crystal size continues to decrease monotonously (Figures 20 and 21).…”

Section: Deformation-induced Morphology Evolution During Uniaxial Str...mentioning

confidence: 99%

Evolution of the Deformation‐ and Flow‐Induced Crystallization and Characterization of the Microstructure of a Single Spherulite, Lamella, and Chain of Isotactic Polypropylene

Sharaf,

Kloczkowski

2023

Macro Chemistry & Physics

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Isotactic polypropylene (iPP) is a frequently used polymer in industrial processing and scientific research, used as a model material. This review highlights some current and forefront issues in polymer science and engineering. This review alludes to classical deformation schemes to interpret the complicated deformation in isotactic polypropylene as a semicrystalline polymer. Also, due to the complex hierarchical structures of crystallized polymers, we are concerned mainly with the progress on the multi‐scale and multi‐stage microstructural evolution covering each deformation stage from the initiation of plasticity until failure, particularly in terms of crystalline morphology changes. Specifically, the characterization of the microstructure evolution of a single spherulite, lamella, and chain of isotactic polypropylene will be emphasized and mentioned. Here, we are most interested in the results obtained from stretching (strain‐induced) orientation and crystallization studies accompanied by the in situ scattering and spectroscopy techniques offering a detection window from nano to micrometer scale, which should be able to reflect the microstructural changes at different length scales of interest.During polymer processing, the melts are frequently subjected to shear or/and elongation flow fields, producing flow‐induced molecular chain orientation in the melt. The oriented molecular chains crystallize differently than those encountered under quiescent conditions. Thus, orientation‐induced crystallization has long been an object of intense interest. A vast body of research was reported about the effects of preorientation on the crystallization of various polymers. Among them, iPP is most frequently studied since its diversified structure and morphology are very sensitive to changes in processing conditions and molecular parameters.This article is protected by copyright. All rights reserved

show abstract

Temperature dependency of cavitation in impact copolymer polypropylene during stretching

Cited by 12 publications

References 55 publications

Time-Resolved SAXS/WAXD under Tensile Deformation: Role of Segmental Ethylene–Propylene Copolymers in Impact-Resistant Polypropylene Copolymers

Time-Resolved SAXS/WAXD under Tensile Deformation: Role of Segmental Ethylene–Propylene Copolymers in Impact-Resistant Polypropylene Copolymers

Influence of crystal orientation on stretching induced void formation in poly(4‐methyl‐1‐pentene) investigated by in‐situ small‐angle and wide‐angle X‐ ray scattering

Evolution of the Deformation‐ and Flow‐Induced Crystallization and Characterization of the Microstructure of a Single Spherulite, Lamella, and Chain of Isotactic Polypropylene

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