Sulfonated Poly(ether ether ketone) Ionomers and Their High Temperature Shape Memory Behavior

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• 作者：Ying Shi ; R. A. Weiss
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：March 11, 2014
• 年：2014
• 卷：47
• 期：5
• 页码：1732-1740
• 全文大小：409K
• 年卷期：v.47,no.5(March 11, 2014)
• ISSN：1520-5835

文摘

High temperature shape memory polymers (SMP) were prepared from metal salts of a sulfonated poly(ether ether ketone) ionomer, M-SPEEK, using cations of varying valence from one to four. The ionomers were prepared by neutralizing a SPEEK with 18 mol % sulfonation (ion exchange capacity = 0.60 mequiv/g) with Na⁺, Zn²⁺, Ba²⁺, Al³⁺, and Zr⁴⁺. The glass transition temperatures (T_g) of M-SPEEK ionomers increased with increasing Coulomb energy of the ion pair, which provided a range of switching temperatures for shape memory behavior of 224 to 288 掳C. The ionomers were completely amorphous and thermally stable to 300 掳C, at which desulfonation occurred. The modulus of the ionomers above T_g was high, 1鈥?00 MPa, due to dipole鈥揹ipole or ionic supramolecular bonding of the sulfonate groups that formed the permanent network for shape memory. The water absorption of the ionomers ranged from about 5 to 16 wt %, depending on the nature of the cation. Na-SPEEK exhibited relatively poor shape memory behavior with fixity (F) and recovery (R) values of about 80% and 45%, respectively, but the ionomers prepared with multivalent cations had F and R values greater than 90% that were reproducible over multiple shape memory cycles.