Shear Induced Irreversible Gelation through Physical Network Formation

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• 作者：Tahmineh Mahmoudi ; Vahid Karimkhani ; Gwang Seok Song ; Dai Soo Lee ; Florian J. Stadler
• 刊名：Macromolecules
• 出版年：2013
• 出版时间：May 28, 2013
• 年：2013
• 卷：46
• 期：10
• 页码：4141-4150
• 全文大小：540K
• 年卷期：v.46,no.10(May 28, 2013)
• ISSN：1520-5835

文摘

A resin mixture of vinyl ester and carboxyl terminated butadiene diluted with styrene shows an increase of viscosity when shearing the sample. Unlike previous reports on rheopexy and shear induced gelation of unfilled systems, this behavior leads to permanently elevated levels of viscosity. FT-IR found no indication of a chemical reaction, and therefore, the changes must be physical in nature鈥攂elieved to be an increase in the number of hydrogen bonds. On the basis of the results, it is concluded that a physical network based on supramolecular attractions between the 鈭扖OOH groups of the carboxyl terminated butadiene is formed, which leads to a time-dependent behavior and increase in viscosity at certain shear rate, at longer shearing times. This is a new effect, which we call 鈥渋rreversible shear induced gelation by supramolecular bonding鈥?