Triple Shape Memory Materials Incorporating Two Distinct Polymer Networks Formed by Selective Thiol-Michael Addition Reactions
Triple Shape Memory Materials Incorporating Two Distinct Polymer Networks Formed by Selective Thiol-Michael Addition Reactions
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DOI：
10.1021/ma501028a
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发表时间：
2014-08-12
期刊：
影响因子：
5.5
通讯作者：
Bowman, Christopher N.
中科院分区：
文献类型：
--
作者：
Chatani, Shunsuke;Wang, Chen;Bowman, Christopher N.
我们提出了一种复合材料组成的双重聚合物网络独特地形成从一个单一的反应类型和催化剂，但涉及单体具有显着不同的反应性。这种强大的新方法来创建聚合物网络产生两个窄的玻璃化转变，均匀的网络顺序从一个单一的反应，但所有单体的存在和均匀混合之前的任何聚合。这些材料表现出三重形状记忆效应的基础上的双重聚合物网络，这都是使用硫醇迈克尔加成反应形成的。两种多官能硫醇单体（即，巯基乙酸酯（MA）和巯基丙酸酯（MP））和两种多官能乙烯基（即，乙烯基砜（V）和丙烯酸酯（A））使用亲核引发剂原位聚合。首先产生与较高官能团反应性相关的MA-V聚合物网络（T-g = 55 ℃），然后形成MP-A网络（T-g = 10 ℃），这通过FT-IR、SEM、DMA和单独制备的由嵌入MP-A基质中的MA-V颗粒组成的复合聚合物来证实。三重形状记忆效应的特点是使用DMA，它表明，可以通过一个步骤（单一温度）或两个步骤的方法（两个不同的温度）编程的形状。该材料能够在其两个T（g）之间的中间温度（20 ℃）下保持其过渡形状延长的时间段（>1 h），这主要是由于两个单独网络的窄过渡。这种获得具有不同转变和特征的双重聚合物网络的新方法简单而稳健，从而能够在三重形状记忆聚合物，生物医学材料和复合材料等领域中应用。
We present a composite material composed of dual polymer networks uniquely formed from a single reaction type and catalyst but involving monomers with dramatically different reactivities. This powerful new approach to creating polymer networks produces two narrow glass transition, homogeneous networks sequentially from a single reaction but with all monomers present and uniformly mixed prior to any polymerization. These materials exhibit a triple shape memory effect based on the dual polymer networks, which were both formed using the thiol Michael addition reaction. Two multifunctional thiol monomers (i.e., mercaptoacetate (MA) and mercaptopropionate (MP)) and two multifunctional vinyls (i.e., vinyl sulfone (V) and acrylate (A)) were polymerized in situ using a nucleophilic initiator. The MA-V polymer network (T-g = 55 degrees C) was generated first associated with the higher functional group reactivities followed by the formation of the MP-A network (T-g = 10 degrees C) which was confirmed by FT-IR, SEM, DMA, and a separately prepared composite polymer consisting of MA-V particles embedded in an MP-A matrix. The triple shape memory effect was characterized using DMA, and it was demonstrated that the shapes could be programmed either by a one-step (single temperature) or a two-step method (two different temperatures). This material was able to hold its transitional shape for an extended time period (>1 h) at intermediate temperature (20 degrees C) between its two T(g)s, mainly due to narrow transitions of two separate networks. This new approach to obtain dual polymer networks with distinct transitions and characteristics is simple and robust, thus enabling applications in areas such as triple shape memory polymers, biomedical materials, and composites.