Effect of lanthanum-modified magnesium silicate on isotactic polypropylene crystallization in composite materials during shear flow |
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| Authors: | Wojciech H. Bednarek Filip Ciesielczyk Majka Odalanowska Dominik Paukszta Adam Piasecki |
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| Affiliation: | 1. Institute of Chemical Technology and Engineering, Faculty of Chemical Technology Poznan University of Technology, Poznan, Poland;2. Institute of Materials Science and Engineering, Faculty of Mechanical Engineering and Managment Poznan University of Technology, Poznan, Poland |
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| Abstract: | The activity of isotactic polypropylene (iPP) nucleating additives during shear flow of composite materials is still not entirely explained. In current work the sol-gel method was employed to synthesize MgO·SiO2 filler, surface-modified with trivalent lanthanum. The crystallization of commercial iPP in the presence of 0.5% by weight La3+ modified or unmodified silicates was analyzed. The wide angle X-ray scattering analysis proved that the presence of even small amount of filler influences significantly on supermolecular structure of iPP. The results of microscope observations confirmed that the lanthanum-modified filler shows the nucleating ability for iPP. In that case a significant reduction of crystallization induction time was noticed. The investigation of iPP crystallization in composites after shear treatment confirmed that the increase of shear rate reduces the nucleating ability of additives. Moreover, the flow of filler particles during shearing may impede the shear-induced crystallization phenomenon. |
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| Keywords: | crystallization nucleation polypropylene shear spherulites |
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