Nucleation effects of sodium and ammonium salts of 2,2′‐methylene‐bis‐(4,6‐di‐t‐butylphenylene)phosphate in isotactic polypropylene

The nucleation ability of isotactic poly(propylene) (iPP) to ammonium 2,2′‐methylene‐bis‐(4,6‐di‐t‐butylphenylene) phosphate (An) was investigated in the present work comparing with sodium 2,2′‐methylene‐bis‐(4,6‐di‐t‐butylphenylene) phosphate (NA‐11). Scanning electron microscope (SEM) revealed the crystalline morphology of both An and NA‐11 with planar surface characteristics. The observation of the fracture surface of nucleation iPP samples by SEM showed An particles were dispersed uniformly in polymer and had a better compatibility with iPP matrix than NA‐11 particles. Differential scanning calorimeter (DSC) showed that the melting temperature of An was 262°C significantly lower than that measured from NA‐11 group (above 400°C). Crystallization behaviors of iPP/NA‐11 and iPP/An were also investigated by DSC analysis, respectively. The results showed the crystallization peak temperature and the crystallinity of iPP/An were almost near to that of iPP/NA‐11. Furthermore, mechanical and optical properties of iPP were strongly improved in the presences of An and NA‐11. The flexural strength of iPP was elevated 34 and 35% and the haze value was reduced from 40.4 to 15.1 and 14.9% by the addition of 0.15 wt% NA‐11 and An, respectively. These results demonstrate that the nucleating agent of An described here is a good nucleating agent for the crystallization of iPP as well as NA‐11. POLYM. ENG. SCI., 55: 22–28, 2015. © 2014 Society of Plastics Engineers