417643 The Crystallization Behavior of Isotactic Polypropylene Induced By a Novel Anti-Nucleating Agent and Its Inhibition Mechanism of Nucleation

Sunday, November 8, 2015: 5:15 PM
251C (Salt Palace Convention Center)
Shicheng Zhao1, Xin Yu2, Hanzhang Gong2 and Zhong Xin3, (1)State-Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, China, (2)State-Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, China, (3)State Key Laboratory of Chemical Engineering, East China University of Science and Technology, School of Chemical Engineering, Shanghai, China

2015 AIChE Annual Meeting

The crystallization behavior of isotactic polypropylene induced by a novel anti-nucleating agent and its inhibition mechanism of nucleation

Shicheng Zhao, Xin Yu, Hanzhang Gong, Zhong Xin*

Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, State-Key Laboratory of Chemical Engineering, Department of Production Engineering, East China University of Science and Technology, Shanghai, 200237, People's Republic of China

Abstract: The addition of foreign substances is well known to be able to improve the crystallization of iPP following a nucleation-promoting mechanism. In the present work, however, we found that zinc salt of 1, 4, 5, 6, 7, 7-hexachlorobicyclo [2.2.1] hept-5-ene-2,3-dicarboxylic acid (HCHD-Zn) unexpectedly decreased the crystallization temperature (Tcp) and rate of iPP, generating remarkable anti-nucleation effects. The results of differential scanning calorimetry (DSC) and polarized optical microscopy (POM) showed Tcp of iPP decreased more than 4 oC and nucleation densities of iPP decreased nearly 70% upon the addition of the "anti-nucleating agent" HCHD-Zn. Isothermal crystallization kinetics indicated HCHD-Zn lowered the crystallization kinetic constant k of iPP but had similar Avrami exponent n value with neat iPP, which revealed HCHD-Zn hindered the crystallization of iPP but did not change the type of nucleation and growth of iPP. We propose a mechanism of anti-nucleation of iPP upon the addition of HCHD-Zn from a structural perspective. The removal of hydrochloride left a 3D network of iPP chains cross-linked by HCHD-Zn particles. Therefore, the restricted movement of polymer chains inhibited the nucleation of iPP.

Key words: Polypropylene, Anti-nucleating agent, Crystallization behavior, Inhibition mechanism

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See more of this Session: Polymer Processing and Rheology
See more of this Group/Topical: Materials Engineering and Sciences Division