Flow Memory and Stability of Shear-Induced Nucleation Precursors in Isotactic Polypropylene

被引：133

作者：

Cavallo, Dario ^{[1
]}

Azzurri, Fiorenza ^{[1
]}

Balzano, Luigi ^{[2
]}

Funari, Sergio S. ^{[3
]}

Alfonso, Giovanni C. ^{[1
]}

机构：

[1] Univ Genoa, Dipartimento Chim & Chim Ind, I-16146 Genoa, Italy

[2] Eindhoven Univ Technol, Dept Mech Engn, NL-5600 MB Eindhoven, Netherlands

[3] Deutsch Elektronensynchrotron DESY, Hamburger Synchrotronstrahlungslab HASYLAB, D-22603 Hamburg, Germany

来源：

MACROMOLECULES | 2010年 / 43卷 / 22期

关键词：

SIMULTANEOUS SMALL-ANGLE; X-RAY-SCATTERING; INDUCED CRYSTALLIZATION; MOLECULAR-WEIGHT; SHISH-KEBAB; ENHANCED CRYSTALLIZATION; INDUCED ORIENTATION; THERMAL-STABILITY; I-PP; MELT;

D O I：

10.1021/ma1020193

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 [高分子化学与物理];

摘要：

The dissolution of flow induced nucleation precursors in isotactic polypropylene is investigated indirectly by means of in situ rheo-SAXS measurements The progress of crystallization and the evolution of crystal orientation are recorded in isothermal conditions after a controlled shear step followed by an annealing step of different duration at various melt temperatures The results confirm that the survival time of shear-induced nucleation precursors is extremely large compared to typical theological relaxation times and it is longer for the precursors originated at higher shear rate Most important, we show that the effect of flow on the development of oriented morphologies is lost much earlier than that on the overall crystallization kinetics A schematic model for precursors' dissolution involving gradual transformation from row into point-like nuclei is proposed

引用

页码：9394 / 9400

页数：7

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