文献类型：期刊文献

英文题名：Enhancement of"in-situ" dispersed NA11 for the mechanical and crystallization properties of polypropylene

作者：Gao, Jin[1];Meng, Xin[1];Deng, Zhaopeng[1];Xin, Zhong[1];Tong, Chuangchuang[1]

机构：[1]East China Univ Sci & Technol, Sch Chem Engn, Mat Chem Engn & Prod Engn Dept, Shanghai Key Lab Multiphase, Shanghai 200237, Peoples R China

年份：2022

卷号：29

期号：5

外文期刊名：JOURNAL OF POLYMER RESEARCH

收录：;EI(收录号：20221611982373);WOS:【SCI-EXPANDED(收录号:WOS:000782604700002)】；

基金：This work was supported by the National Natural Science Foundation of China (Grant Number 21776079).

语种：英文

外文关键词：Polypropylene; Organophosphate; Sodium stearate; In-situ reaction; Dispersion; Nucleating agent

摘要：Sodium 2,2'-methylene-bis(4,6-di-tertbutylphenyl)-phosphate (NA11) is an alpha-type nucleating agent for improving the mechanical and crystallization performances of isotactic polypropylene (iPP). However, the limited dispersibility of NA11 inhibits its nucleation. The in-situ nucleation method was used to fabricate well-dispersed NA11. Based on the free energy of the reaction between the two precursors of 2,2'-methylene-bis-(4,6-di-tert-butylphenyl) phosphate (MBP) and sodium stearate (NaSt) obtained via simulations, NA11 may form in situ during the melt processing of iPP. Furthermore, thermogravimetric and Fourier transform infrared spectroscopic results indicated that MBP and NaSt disappeared with the appearance of NA11 and stearic acid (HSt) during heating, providing favorable proofs for the formation of in-situ NA11 [NA11(IS)]. NA11(IS) exhibited better dispersion than NA11 in iPP, thus efficiently improving the mechanical and crystallization performances of iPP. At the NA11(IS) of similar to 0.1 wt%, the tensile strength and flexural modulus of iPP improved by 18.8% and 55.7%, respectively, compared to pure iPP, while equimolar NA11 prepared by traditional method mixed with iPP could not reach such achievement. Moreover, NA11(IS) increased the crystallization peak temperature of iPP by 13.6 degrees C, with a reduced activation energy of iPP crystallization and the accelerated crystallization rate. Therefore, well-dispersed NA11(IS) may provide more nucleation sites for iPP, resulting in the enhanced nucleation of NA11(IS) and improved performances of iPP. Based on this work, the in-situ nucleation method is potentially applied to a vast area of research, to realize high dispersion of additives in the matrix.