Crystallization, mechanical, and heat resistance performances of copolymer polypropylene modified by α nucleating agent

Abstract

Polypropylene (PP) was a very practical and important thermoplastic, which was widely used in various fields due to its low cost, universal, and corrosion resistance. However, the moderate mechanical and heat resistance properties of PP limited its application in some special fields. In this paper, nucleating agents NP-657 were added to further improve its mechanical and heat resistance performances of PP (300H). Furthermore, the heterogeneous nucleation of NP-657 reduced the crystal size and increased the crystal density of 300H. With the rise of NP-657 content, the crystallization rate of different PP systems increased significantly, such as the t1/2 of 300H-0.2 reduced by 31.9 min in comparison with that of 300H at 140°C. At the same time, the crystallinity of 300H-0.05 with 0.05 wt.% NP-657 increased by about 5.96% compared with 300H. In addition, 300H-0.05 has the highest tensile strength (23.9 ± 0.6 MPa), flexural modulus (1273.3 ± 67.3 MPa), and the highest thermal deformation temperature (88.5 ± 7.7°C) in different PP systems. In general, this paper provided a reference for the fabrication of PP with satisfactory mechanical and heat resistance performances. Highlights: 300H-0.05 had a maximum crystallinity of 40.8 ± 0.2% in different PP systems. The flexural modulus of 300H-0.05 was 434 MPa higher than that of 300H. The tensile strength of 300H-0.05 increased to 23.9 ± 0.6 MPa. 300H had the highest thermal deformation temperature of 88.5 ± 7.7°C.