Accessible Unlicensed Requires Authentication Published by De Gruyter November 16, 2021

Influence of Crystal Structure on Thermo-Mechanical Properties of Injection Molded 𝛃-Nucleated iPP

A. Hamza, R. K. Arya, A. D. Palsodkar, G. R. Bhadu and S. J. A. Rizvi


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.

* Syed J. A. Rizvi, Department of Petroleum Studies, Faculty of Engineering and Technology, A.M.U., Aligarh – 202 002, U.P., India


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Received: 2021-03-02
Accepted: 2021-04-26
Published Online: 2021-11-16

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