Improved impact property of long glass fiber-reinforced polypropylene random copolymer composites toughened with beta-nucleating agent via tunning the crystallization and phase

Abstract

Crystallization and phase engineering offer a promising route to significantly improve the impact property of long glass fiber-reinforced polypropylene random copolymer (LGF/PPR) composites. However, the nucleation and crystallization mechanism in the crystallization process, and the resulting phase change mechanism are still unclear, which severely limits the remarkable improvement of the toughness of LGF/PPR composites. Herein, we successfully fabricate toughened LGF/PPR composites with excellent heat deflection temperature and impact toughness via tuning the crystallization behavior and phase structure generated by introducing β-nucleating agent (β-NA). Through differential scanning calorimeter and wide-angle X-ray diffraction analysis, the influence of LGF and β-NA on the nucleation and crystallization mechanism of the PPR matrix was revealed. Therefore, the critical crystallization parameters were calculated, and then the correlation was established with tensile and impact properties through regression analysis. The results show that the impact strength of β-PPR and β-LGF/PPR/MPPR are remarkably increased by 50.1% and 26.3% at the critical β-NA content of 0.2 and 0.1 wt%, respectively, due to the intrinsic toughening mechanism. This work may pave the way for preparing a class of LGF/PPR composites with high-impact toughness.