Styrene/Butadiene Gradient Block Copolymers: Molecular and Mesoscopic Structures

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• 作者：St&eacute ; phane Jouenne ; Juan A. Gonzá ; lez-Leó ; n ; Anne-Val&eacute ; rie Ruzette ; Philippe Lodefier ; Sylvie Tenc&eacute ; -Girault ; Ludwik Leibler
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：April 3, 2007
• 年：2007
• 卷：40
• 期：7
• 页码：2432 - 2442
• 全文大小：766K
• 年卷期：v.40,no.7(April 3, 2007)
• ISSN：1520-5835

文摘

Rubbery-glassy block copolymer dispersions are an attractive solution for toughening rigidthermoplastics like polystyrene without affecting optical transparency. An interesting facet of the copolymersused is molecular disorder, artificially introduced during anionic synthesis through composition gradients alongthe copolymer chain and/or blending and partial coupling of different copolymers. In particular, this level ofdisorder is apparently a key to achieve the desired PS/copolymer blend morphologies and properties in shortprocessing times. In this work, we investigate the role of these "synthesis imperfections" on self-assembly ofstyrene-rich asymmetric gradient triblock copolymers, denoted S1-G-S2, where Si are pure polystyrene blocksand G is a gradient copolymer of styrene and butadiene. Kinetic modeling of conversion data is used to predictgradient composition profiles for the anionic copolymerization conditions used. Self-assembly, dynamic viscoelasticbehavior, and experimentally determined mesoscopic composition profiles across microdomains are discussed inlight of the particular copolymer structure.