A REAL-TIME AFM STUDY ON CRYSTAL NUCLEATION AND GROWTH IN NANODROPLETS OF ISOTACTIC POLYPROPYLENE  

作　　者：Jun-chai Zhao Bo Xing Zheng Peng Jian-min Zhang 

机构地区：[1]School of Material Science and Engineering, Shijiazhuang Tiedao University

出　　处：《Chinese Journal of Polymer Science》2013年第9期1310-1320,共11页高分子科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 20804051);the Natural Science Foundation of Hebei Province (Nos. B2010001055, E2011210059)

摘　　要：Isotactic polypropylene （iPP） nanodroplets were prepared by using the classical droplet method in this study. The formation of nanodroplets allowed the controlled observation of polymer nucleation as well as access to crystal growth at exceptionally high supercooling in /PP. Three cases including the heterogeneous nucleation and fast crystallization in iPP droplets, the formation of multiple independent homogeneous nuclei within a single droplet and a single nucleus within a single droplet were detected by using atomic force microscopy （AFM） during gradually cooling after remelting the nanodroplets. Moreover, it is found that when the volume of droplet is larger than the value of ca. 130000 nm3, the first case was observed. Otherwise, the latter two cases appeared. The temperature at which the onset of nucleation was observed in individual droplets was found to be mainly dependent on height of the droplets when the size scale of the droplet is comparable to the size of the critical nucleus in at least one dimension, which indicates the nucleation behavior under confinement.Isotactic polypropylene （iPP） nanodroplets were prepared by using the classical droplet method in this study. The formation of nanodroplets allowed the controlled observation of polymer nucleation as well as access to crystal growth at exceptionally high supercooling in /PP. Three cases including the heterogeneous nucleation and fast crystallization in iPP droplets, the formation of multiple independent homogeneous nuclei within a single droplet and a single nucleus within a single droplet were detected by using atomic force microscopy （AFM） during gradually cooling after remelting the nanodroplets. Moreover, it is found that when the volume of droplet is larger than the value of ca. 130000 nm3, the first case was observed. Otherwise, the latter two cases appeared. The temperature at which the onset of nucleation was observed in individual droplets was found to be mainly dependent on height of the droplets when the size scale of the droplet is comparable to the size of the critical nucleus in at least one dimension, which indicates the nucleation behavior under confinement.

关 键 词：Atomic force microscopy （AFM） Isotactic polypropylene （iPP） NANODROPLETS Homogeneous nucleation. 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业] TP311.56[自动化与计算机技术—计算机软件与理论]