Intrinsic crazes in polycarbonate: Phenomenology and molecular interpretation of a new phenomenon

Dettenmaier, M.

doi:10.1007/bfb0024056

Cited by 34 publications

(12 citation statements)

References 163 publications

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“…The decrease of the molecular orientation and the ductile‐to‐brittle transition with increasing temperature is opposite to that observed in PMMA, i.e., molecular orientation is enhanced in PMMA by accelerated molecular motion and the breaking of molecular chains is suppressed at elevated temperatures . As mentioned before, the embrittlement of polycarbonate with increasing temperature is not observed when the molecular weight is high . Thus, the ductile‐to‐brittle transition by the decrease of the molecular orientation at elevated temperature is attributed to the disentanglement of molecular chains by accelerated molecular motion for low molecular weight polycarbonate such as OD‐PC.…”

Section: Resultsmentioning

confidence: 70%

“…That is, ductile‐to‐brittle transition occurred in the OD‐PC at elevated temperatures. Since the ductile‐to‐brittle transition with increasing temperature is not observed in polycarbonate when the molecular weight is high , it is characteristic on the low molecular weight polycarbonate such as OD‐PC.…”

Section: Resultsmentioning

confidence: 99%

“…Scission crazing usually occurs at low temperatures and at a high strain rate, while disentanglement crazing occurs at high temperatures and at a low strain rate. In polycarbonate, disentanglement crazing due to accelerated molecular motion was found to occur at high temperature , but the related brittle property was not reported . Hence, details of the brittle behavior have not been explained, though the ductile‐to‐brittle transition by elevated temperature has been known for OD‐PC in the manufacture.…”

Section: Introductionmentioning

confidence: 99%

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Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Taguchi

Miike

Hatakeyama

et al. 2017

Polymer Engineering & Sci

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We investigated the stress-strain behavior of low molecular weight polycarbonate for optical disc grade (OD-PC) under carbon dioxide (CO 2 ) at various pressures, and compared the results with that under ambient pressure at various temperatures. Elongation at break decreased sharply with increased CO 2 pressure at around 2 MPa, while the elastic modulus decreased gradually up to 6 MPa. These results indicate that the tensile property changed from ductile to brittle with increased CO 2 pressure, although the molecular motion is accelerated due to the plasticization effect of CO 2 . Such ductile-to-brittle transition is similar to that observed under elevated temperatures caused by chain disentanglement due to accelerated molecular motion. Although the changes of tensile properties were similar, the craze structure obtained by the brittle behavior was different, i.e., a filamented-craze structure was obtained under high-pressure CO 2 , while a lace-like one was obtained under elevated temperatures. POLYM. ENG. SCI., 58:683-690, 2018.

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Section: Resultsmentioning

confidence: 70%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Taguchi

Miike

Hatakeyama

et al. 2017

Polymer Engineering & Sci

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“…In terms of physics, introduction of filler particles into polymer matrix is equivalent to creation of numerous defects in matrix. As is known from literature, defects in glassy polymers at T < T g promote premature failure of samples (especially, due to initiation of crazing under loading), since these defects are concentrators of stress. Generally speaking, the presence of defects such as clusters and cracks in the as‐prepared composite films cannot result in improvement of mechanical properties of composites as compared to those of films prepared from the matrix PS.…”

Section: Resultsmentioning

confidence: 99%

Destructive changes of polymer matrices during preparation, storage, and mechanical testing of neat and C₆₀‐filled polystyrene films

Chubarova

Lebedeva

Melenevskaya

et al. 2016

J of Applied Polymer Sci

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Mechanical properties of filled and neat polystyrene films prepared under the same conditions have been studied. Composite films have been obtained from mixed dilute solutions of polystyrene and C 60 fullerene in various solvents by solvent evaporation on glass substrate. Morphology of the composite films has been shown to depend on preparation conditions and to change both with time and during deformation. Mechanical parameters obtained in tensile tests and by dynamic mechanical analysis of filled and unfilled samples have been found to change with molecular weight of the matrix and preparation conditions as well as during testing. Variability of mechanical properties has been shown to be the effect of destructive changes in polymer matrices during preparation, storage, and deformation.

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“…Ebenso können Orientierung und/oder Spannungen im Bauteil zu einem Abfall weiterer Eigenschaften führen. So kann beispielsweise das Spannungsrissverhalten deutlich verschlechtert werden [23,36]. Ebenso können optische Kennwerte durch Orientierungen und Eigenspannungen beeinflusst werden [37].…”

Section: Einfluss Innerer Eigenschaften Auf Das Mechanische Materialvunclassified

Prozess- und Eigenschaftsbeeinflussung dünnwandiger Spritzgießteile mittels dynamisch temperierten Rapid Tooling Spritzgießwerkzeugen

Drummer¹

2016

Zeitschrift Kunststofftechnik

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Prozess-und Eigenschaftsbeeinflussung dünnwandiger Spritzgießteile mittels dynamisch temperierten Rapid Tooling Spritzgießwerkzeugen Beim Spritzgießen von dünnwandigen Bauteilen führen die schnelle Abkühlung zu einer strukturell veränderten Morphologie sowie fließbedingte Dehn-und Scherströmungen zu hohen Molekülorientierungen. Insbesondere Letzteres kann zu einer deutlichen Anisotropie der Eigenschaften führen. Die hier vorgestellten Arbeiten mit Rapid Tooling Werkzeugeinsätzen zeigen, dass angepasste Werkzeugtemperaturen beim Einspritzen eine Homogenisierung der kristallinen Strukturen und Orientierungen ermöglichen. Insbesondere eine Verzögerung des Abkühlens nach dem Einspritzen erlaubt eine deutliche Reduktion von molekularen Orientierungen. Die angepassten Verarbeitungsbedingungen beeinflussen letztlich auch die lokalen mechanischen Eigenschaften in einem Spritzgießteil. Affecting processing and properties of injection moulded thin-wall parts using dynamic tempered Rapid Tooling moulds In injection moulding of thin-wall parts the fast cooling velocity leads to a modified inner structure as well the shear and elongational flow to high molecular orientations. This results in significant anisotropy of mechanical properties. Especially the latter can lead to a significant anisotropy of the part properties. This work deals with Rapid Tooling moulds show that adapted mould temperatures during injection moulding favour the homogenization of the crystalline structure and molecular orientations respectively. In particular, a delay of cooling after melt injection allows a significant reduction of molecular orientations. Consequently, the adjusted processing conditions affect the local mechanical properties in a molded part.

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Intrinsic crazes in polycarbonate: Phenomenology and molecular interpretation of a new phenomenon

Cited by 34 publications

References 163 publications

Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Destructive changes of polymer matrices during preparation, storage, and mechanical testing of neat and C₆₀‐filled polystyrene films

Prozess- und Eigenschaftsbeeinflussung dünnwandiger Spritzgießteile mittels dynamisch temperierten Rapid Tooling Spritzgießwerkzeugen

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Intrinsic crazes in polycarbonate: Phenomenology and molecular interpretation of a new phenomenon

Cited by 34 publications

References 163 publications

Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Ductile‐to‐brittle transition behavior of low molecular weight polycarbonate under carbon dioxide

Destructive changes of polymer matrices during preparation, storage, and mechanical testing of neat and C60‐filled polystyrene films

Prozess- und Eigenschaftsbeeinflussung dünnwandiger Spritzgießteile mittels dynamisch temperierten Rapid Tooling Spritzgießwerkzeugen

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Destructive changes of polymer matrices during preparation, storage, and mechanical testing of neat and C₆₀‐filled polystyrene films