Influence of Crystal Structure on Thermo-Mechanical Properties of Injection Molded 𝛃-Nucleated iPP
| Autor: | A. Hamza, S. J. A. Rizvi, G. R. Bhadu, A. D. Palsodkar, R. K. Arya |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | International Polymer Processing. 36:545-556 |
| ISSN: | 2195-8602 0930-777X |
| Popis: | Isotactic polypropylene (iPP) was nucleated in-situ with calcium pimelate during melt compounding. Calcium pimelate is a highly effective β-nucleator for isotactic polypropylene (iPP). The β-nucleated iPP was characterized by wide angle x-ray diffraction (WAXD) and differential scanning calorimetry (DSC) for its crystallinity and crystal structure. In addition, the injection-molded samples were tested for thermo-mechanical properties. It is found that very low quantity (< 0.1 wt. %) of β-nucleator is required to produce sufficiently high β-crystal fraction (Kβ) in isotactic polypropylene. β-nucleated iPP shows increment of 11 to 14 °C in its heat deflection temperature (HDT). It was also observed that slow cooling rate of β-nucleated iPP promotes the formation of β-crystals and that tensile stretching leads to complete transformation of β crystals into a-crystals at room temperature. It was also revealed that the presence of maleic anhydride grafted polypropylene (PP-g-MA), a well-known coupling agent (or compatibilizer), may reduce the (Kβ) value to a marginal extent. It was also observed that the thermo-mechanical properties were not much affected by the presence of PP-g-MA. Therefore, calcium pimelate may be used as β-nucleator in case of neat as well as reinforced polypropylene containing maleic anhydride as coupling agent. |
| Databáze: | OpenAIRE |
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