China Plastics ›› 2022, Vol. 36 ›› Issue (12): 100-107.DOI: 10.19491/j.issn.1001-9278.2022.12.015

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Preparation of two carboxylate nucleating agents and their nucleation effect on polypropylene

ZHANG Zewen1, ZHU Enci1, ZHANG Xixiang1, WEI Lijuan2, ZHAO Shicheng1()   

  1. 1.Shanghai Key Laboratory of Multiphase Materials Chemical Engineering,School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China
    2.North Huajin Chemical Industries Group Corporation,Panjin 124021,China
  • Received:2022-09-02 Online:2022-12-26 Published:2022-12-20

Abstract:

Two types of α⁃form nucleating agents with a similar chemical structure, sodium bicyclo[2.2.1]hept⁃5⁃ene⁃2,3⁃dicarboxylate (NA1) and sodium bicyclo[2.2.1]heptane⁃2,3⁃dicarboxylate (NA2), were synthesized, and their nucleation effects on the crystallization behavior of isotactic polypropylene (iPP) was studied. The crystallization temperature and crystal morphology of iPP nucleated with the two nucleating agents were investigated using differential scanning calorimetry and polarized optical microscope (PLM). The results indicated that the crystallization peak temperature of iPP increased by 14.5 ℃ and 16.0 ℃ at 0.3 wt % NA1 and NA2, respectively. Meanwhile, the two nucleating agents could refine the spherical crystal size of iPP significantly. The nucleated iPP was characterized using wide⁃angle X⁃ray diffraction. Both of two nucleating agents were found to induce the formation of α⁃form crystalline polypropylene, indicating good α⁃form nucleation effectiveness. The mechanical properties of the nucleated polypropylene were characterized. The nucleated polypropylene exhibited an increase in tensile strength and flexural modulus at first and then tended to be stable with increasing the contents of two nucleating agents. Compared to pure iPP, the tensile strength of the nucleated iPP increased by 4.6 % and 8.6 % at 0.05 wt % NA1 and NA2, respectively. The iPP nucleated with 0.05 wt % NA1 and NA2 also showed an increase in flexural modulus by 8.2 % and 21.7 %, respectively, and its impact strength keep stable basically.

Key words: isotactic polypropylene, α nucleating agent, crystallization behavior, mechanical property, isothermal crystallization kinetics

CLC Number: