The influence of specific nucleation and branching on the properties of blends of polypropylene

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F23%3A63568598" target="_blank" >RIV/70883521:28110/23:63568598 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

The influence of specific nucleation and branching on the properties of blends of polypropylene

Original language description

Isotactic polypropylene (iPP) occupies a privileged position among semi-crystalline polymers due to its excellent mechanical properties. However, iPP has relatively low melt strength and elongation viscosity, which introduces complications in processing technologies that require these properties, such as blow moulding or thermoforming. These problems can be avoided by using long-chain branched polypropylene (LCB-PP), but its higher price hinders its widespread use. Hence, by using blends of linear and branched polypropylene, the desired melt properties can be achieved at an affordable cost [1, 2]. The aim of this work is to study the influence of branching and specific nucleation on the thermal and mechanical properties of polypropylene blends using differential scanning calorimetry, tensile testing and Charpy impact test. Blends of linear and branched polypropylene were prepared in different proportions (LCB-PP content 0, 1, 2, 5, 10, 20, 50 or 100 wt. %) with the addition of a specific β-nucleating agent N,N´-dicyclohexyl-2,6-napthalene dicarboxamide (0 or 0.03 wt. %). Melting thermograms (Figure 1) clearly showed that β-phase formation is significantly suppressed with the addition of LCB-PP to the blends. The presence of only 5 wt. % of LCB-PP in the blend resulted in the almost complete disappearance of the trigonal β-phase. The findings of the melting experiments indicate that blends primarily composed of α-phase, possibly γ-phases, show greater thermodynamic stability than the blends containing mainly β-phase. As shown in Figure 2 Young’s modulus significantly rises with increasing content of LCB-PP in blends, the addition of only 1 wt. % of LCB-PP (BL1) leads to an 18 % increase in modulus compared to L-PP. The highest modulus values can be found in BL20 and BL50, over 30 % increase as compared to L-PP. In the case of pure LCB-PP the small drop can be seen.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10404 - Polymer science

Project

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Continuities

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů