Controlling the dynamics of elastomer networks with multivalent brush architectures
Controlling the dynamics of elastomer networks with multivalent brush architectures
复制标题
用多价刷结构控制弹性体网络的动力学
DOI：
10.1039/d2sm00328g
复制
发表时间：
2022
期刊：
影响因子：
3.4
通讯作者：
Macfarlane Robert J.
中科院分区：
文献类型：
--
作者：
Onoda Michika;Jia Fei;Takeoka Yukikazu;Macfarlane Robert J.
在此，我们报告了一种通过结合具有多价刷结构的聚合物来开发机械增强和动态聚合物网络的设计策略。将两种咪唑官能化聚合物，特别是聚（丙烯酸正丁酯）（PnBA）和聚（聚（丙烯酸正丁酯））（PPnBA）以不同比例与Zn（II）离子共混，从而形成一系列组成一致但网络拓扑不同的弹性体。随着PPnBA重量分数的增加，由于交联密度和配位效率的增加，熔体的熔融温度、平台模量和松弛时间增加。然而，值得注意的是，尽管观察到机械性能有所增加，但流动的活化能 Ea 随着 PPnBA 量的增加而降低。这种独特的行为归因于刷状聚合物的多价性质，这使得 PPnBA 能够产生比线性 PnBA 网络更高的交联密度，即使刷状聚合物含有较低重量分数的咪唑交联。这种降低 Ea 同时提高弹性体机械性能的方法在开发各种软材料（例如自修复或可 3D 打印弹性体结构）方面具有巨大潜力。
Herein, we report a design strategy for developing mechanically enhanced and dynamic polymer networks by incorporating a polymer with multivalent brush architecture. Different ratios of two types of imidazole functionalized polymers, specifically poly(n-butyl acrylate) (PnBA) and poly(poly(n-butyl acrylate)) (PPnBA) were blended with Zn(II) ions, thereby forming a series of elastomers with consistent composition but varying network topologies. As the weight fraction of PPnBA increased, the melting temperature, plateau modulus, and relaxation time of the melt increased because of the increase in the crosslinking density and coordination efficiency. Remarkably, however, the activation energy of the flow, Ea, decreased with increasing amounts of PPnBA despite the observed increases in mechanical properties. This unique behavior is attributed to the multivalent nature of the brush polymer, which allows the PPnBA to generate a higher crosslinking density than networks of linear PnBA, even though the brush polymers contain a lower weight fraction of the imidazole crosslinks. This method of lowering Ea, while improving the mechanical properties of the elastomers has great potential in the development of various soft materials such as self-healing or 3D-printable elastomeric structures.