Blends of Linear and Branched Polypropylene: Effect of Nucleating Agent on Crystallization

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F24%3A63579901" target="_blank" >RIV/70883521:28110/24:63579901 - 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

Blends of Linear and Branched Polypropylene: Effect of Nucleating Agent on Crystallization

Original language description

The aim of this study is to compare the efficiency of commercially available sorbitolbased clarifying agent (NA) and varying amounts of long chain-branched polypropylene (LCBPP) acting as a specific α-nucleating agent for linear polypropylene (PP). LCBPP was found to exhibit a self-nucleation effect leading to significantly faster crystallization and the formation of a fine-grained structure. The sorbitol-based clarifying agent, 1,3;2,4-bis(3,4-dimethyl benzylidene)sorbitol (Millad 3988), in common concentration 0.2 wt.%, and LCBPP in low concentrations of 1, 2, 5 and 10 wt.% were immixed into PP using twin-screw extruder. The comparison of the effect of NA and addition of LCBPP under isothermal conditions on the crystallization process, crystallinity and polymorphic composition was carried out by differential scanning calorimetry and wide-angle X-ray scattering (WAXS) equipped with temperature cell. The results obtained from the thermal analysis revealed a higher effectivity of LCBPP over NA in promoted crystallization, especially at high crystallization temperatures. While NA accelerates crystallization to a certain extent, its efficiency significantly decreases with increasing crystallization temperature, whereas LCBPP consistently demonstrates superior nucleating ability across a range of temperatures. Incorporating LCBPP into PP blends enhances crystallization rates and overall crystallinity, indicating its effectiveness as a nucleating agent even at low concentration of 1 wt. % and most probably even at lower. WAXS analysis shows the morphological evolution of the crystalline phases in the blends during isothermal crystallization. LCBPP facilitates the formation of α- and γ-phases, with the latter disappearing at elevated temperatures. Moreover, adding LCBPP leads to faster crystallization kinetics than nucleated PP and also increases overall crystallinity.

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

2024

Confidentiality

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