The influence of heterogonous nucleation on the processing shrinkage and mechanical properties of polypropylene injection moldings
DOI:
https://doi.org/10.37660/PJTI.2025.25.1.1Keywords:
polypropylene, heterogeneous nucleation, post-molding shrinkage, mechanical propertiesAbstract
The aim of the research was to assess the influence of heterogonous nucleation and conditioning time on the processing shrinkage and mechanical parameters of polypropylene moldings. The tests used commercial polypropylene Moplen HP 500N with NJ STAR NU-100 nucleant in an amount of 0.25%. Processing shrinkage and mechanical properties were tested after 1 h, 24 h, 48 h, 72 h, 164 h, and 504 h after production, respectively. The presence of the nucleant in PP contributed to the increase in primary shrinkage. Molded parts made of nucleated PP changed their dimensions less during conditioning. The use of a nucleating agent therefore results in an increase in the dimensional stability of PP moldings. The addition of the nucleant resulted in a decrease in the Young’s Modulus and Yield Stress. In the Elongation at break case parameter, the presence of the nucleant PP resulted in an increase in this parameter compared to the unmodified material. Despite the deterioration of the mechanical properties of nucleated polypropylene, the use of nucleation contributed to the stabilization of the material and a more accurate prediction of the value of processing shrinkage and mechanical properties over time.
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