The correlation between structure and β-nucleation efficiency of Ba, Sr, Ca and Mg pimelates in isotactic polypropylene

Janevski, Aco and Bogoeva-Gaceva, Gordana and Stefov, Viktor and Najdoski, Metodija (2015) The correlation between structure and β-nucleation efficiency of Ba, Sr, Ca and Mg pimelates in isotactic polypropylene. Macedonian Journal of Chemistry and Chemical Engineering, 34 (1). pp. 189-199. ISSN 1857-5552

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The pimelates of the earth-alkaline elements and pimelic acid have been synthesized and studied. All prepared pimelates are crystallohydrates and Ba and Sr pimelates are isotypic. The obtained com-pounds have been characterized using infrared spectroscopy and X-ray diffraction, and it was found that, near and above the melting temperature of polypropylene, the pimelates of Ba and Sr are crystalline, whereas the ones of Ca and Mg are amorphous. The nucleation activity of these pimelates has been stud-ied in the process of crystallization of polypropylene in non-isothermal conditions and followed by differ-ential scanning calorimetry (at cooling rate Vc = 1–20 K min–1). It was found that their nucleation activity, even at concentration of 0.1 %, differs considerably with regards to the cooling rate, and they induce dif-ferent polymorphic composition of the polymer. The nucleation activity was mostly exhibited by Ca pimelate, and when it was used the content of the β crystalline phase (Uβ) in polypropylene ranged from 0.90 to 0.94, depending on the cooling rate, compared to 0.18–0.35 when Mg pimelate was used. In the polymer crystallized by using Ba and Sr pimelate as nucleators, Uβ ranged from 0.47 to 0.77. Based on the theoretical concepts for nucleation activity of solid substrates, an attempt was made to correlate the structurаl features of the synthesized pimelates with their β-nucleation activity in the process of noniso-thermal crystallization of iPP.

Item Type: Article
Subjects: Natural sciences > Chemical sciences
Engineering and Technology > Materials engineering
Natural sciences > Other natural sciences
Natural sciences > Physical sciences
Divisions: Faculty of Technology
Depositing User: Aco Janevski
Date Deposited: 25 Jun 2015 13:25
Last Modified: 25 Jun 2015 13:25

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