Authors
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Scudla, J. ; Eichhorn, K.-J. ; Raab, M. ; Schmidt, P. ; Jehnichen, D. ; Häußler, L.
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Title
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The Effect of Specific Nucleation on Molecular and Supermolecular Orientation in Isotactic Polypropylene
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Date
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12.08.2002
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Number
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10258
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Abstract
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The molecular and supermolecular orientation, morphology and structural changes observed during cold drawing of injection moulded isotactic polypropylene modified by specific <IMGSRC="/giflibrary/12/agr.gif"BORDER="0">, and <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM"> nucleating agents were studied by polarised photoacoustic FTIR spectroscopy, wide-angle X-ray diffraction and differential scanning calorimetry. Significantly lower molecular orientation was found in the core of the <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM">-nucleated injection moulded specimens as compared to unmodified and <IMGSRC="/giflibrary/12/agr.gif"BORDER="0">-nucleated materials. This has been ascribed to the fast growth of the <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM">-crystallites which inevitably dislocates the flow-induced orientation within the crystalline regions and in their vicinity. Moreover, it was found that the presence of the developed <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM">-crystallites distinctly diminishes the efficiency of the orientational solid-state drawing assessed on both levels of the hierarchical structure (molecular and crystalline). This structural observation is directly connected with macroscopic softening effect of the <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM">-phase: lowering the yield stress and flattening the neck shoulder. Thus, the interrelation between the microstructural and macroscopic effects of the <IMGSRC="/giflibrary/12/bgr.gif"BORDER="0"ALIGN="ABSBOTTOM">-phase could be described as a feedback process.
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Publisher
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Macromolecular Symposia
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Wikidata
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Citation
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Macromolecular Symposia 184 (2002) 371-387
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DOI
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https://doi.org/10.1002/1521-3900(200208)184:1<371::AID-MASY371>3.0.CO;2-L
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Tags
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