Study On Preparation And Nucleation Efficiency Of Amide Carboxylate As βNucleating Agents Of Polypropylene

β-form polypropylene (β-PP) has attracted much attention for its special structure with the characteristics of high impact strength and high heat distortion temperature. However it’s difficult to obtain P-iPP under regular crystallization conditions because β-iPP is thermodynamically metastable. So far, adding P-nucleating agents is the feasible method to obtain commercial β-iPP. So it’s important to research and develop high-efficient, low cost and stable β nucleating agents.In this paper, eight amide carboxylate compounds (Li、Na、K、Mg、Ca、Zn、Ba and Al) were designed and synthesized, and their nucleating efficiency in polypropylene was studied. The results showed that norbornene Lauramide zinc salt (NBDA-30) was an effective nucleating agent of iPP, and the structure of NBDA-30was characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and elemental analysis (EA). The results showed that molecular formula of NBDA-30was C42H6gN2O6·H2O.Secondly, the concentration effects (0-1.0wt%) of nucleating agents on mechanical properties and crystallization and melting behavior of iPP were investigated. The crystalline morphology and the spherulite growth process of NBDA-30nucleating iPP were studied by polarized optical microscopy (POM). The results showed that the impact strength of nucleated iPP could be strongly increased when the adding content of NBDA-30was high. The impact strength of nucleated iPP could be changed from31.75J/m to91.0J/m, which was increased by186%, when the adding content of NBDA-30was0.8wt%. There were different optimal cooling rates for different concentration of NBDA-30, and the optimal cooling rates were inceased with the increase of concentration of NBDA-30. Additionally, the sperilite siza was obviously decresed with the adding of NBDA-30.Finally, the nonisothermal crystallization kinetics of iPP nucleated with different concentration of NBDA-30was described by Caze method, and the Kissinger method was applied to calculate the crystallization activation energy. The results showed that the crystal growth mode was not changed by the adding of NBDA-30. The crystallization activation energy of nucleated iPP was increased with low concentration (≤0.2wt%) of NBDA-30, and decreased with high concentration (≥0.4wt%) of NBDA-30. The crystallization activation energy depended on the impact of both the activation energy of nucleation and and the activation energy of crystal growth. The activation energy of nucleation depended on the concentration of NBDA-30, and the activation energy of crystal growth was increased by the interaction between NBDA-30and iPP chains, which had been proved by Rheometer.