Synthesis, Properties, and Light-Induced Shape Memory Effect of Multiblock Polyesterurethanes Containing Biodegradable Segments and Pendant Cinnamamide Groups

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• 作者：Linbo Wu ; Chunli Jin ; Xiangying Sun
• 刊名：Biomacromolecules
• 出版年：2011
• 出版时间：January 10, 2011
• 年：2011
• 卷：12
• 期：1
• 页码：235-241
• 全文大小：402K
• 年卷期：v.12,no.1(January 10, 2011)
• ISSN：1526-4602

文摘

Novel multiblock polyesterurethanes containing crystalline hard and amorphous soft segments and pendant cinnamamide moieties were designed and synthesized via a two-step polyaddition reaction using N,N-bis(2-hydroxyethyl) cinnamamide (BHECA), biodegradable poly(l,l-lactide) (PLLA), and poly(蔚-caprolactone) (PCL) diols as raw materials and hexamethylene diisocyanate (HDI) as coupling agent and characterized by ¹H NMR, FTIR, UV, DSC, tensile and photomechanical tests, and so on. The copolymers behaved as typical thermoplastic elastomers and showed satisfactory thermal and mechanical properties. They also exhibited light-induced shape memory effect (LSME) at room temperature on exposure to light stimuli. The pendant cinnamamide groups work as photoresponsive molecular switches and provide the polymer with LSME via reversible [2 + 2] cycloaddition cross-linking. The strain fixity (R_f) increases with the content of BHECA and the strain recovery (R_r) increases with the content of PLLA. The R_f reaches 50% at a BHECA content of 20 wt % and the R_r reaches >95% at PLLA content of 50 wt %.