Dynamics of the Topological Network Formed by Movable Crosslinks: Effect of Sliding Motion on Dielectric and Viscoelastic Relaxation Behavior
Dynamics of the Topological Network Formed by Movable Crosslinks: Effect of Sliding Motion on Dielectric and Viscoelastic Relaxation Behavior
复制标题
由可移动交联形成的拓扑网络的动力学：滑动运动对介电和粘弹性弛豫行为的影响
DOI：
10.1021/acs.macromol.0c02568
复制
发表时间：
2021
期刊：
影响因子：
5.5
通讯作者：
Inoue Tadashi
中科院分区：
文献类型：
--
作者：
Kashiwagi Yu;Urakawa Osamu;Zhao Sheng;Takashima Yoshinori;Harada Akira;Inoue Tadashi
我们研究了由轮烷型可移动交联组成的拓扑网络的动力学，所述交联由穿过全乙酰化环糊精的聚（丙烯酸乙酯）主链组成，所述全乙酰化环糊精连接到其他链。我们使用流变学和宽带介电谱测量来分析各种时间和长度尺度上的动力学。可移动的交联被发现在两个不同的时间尺度上影响整个网络的动态。在末端区域，它作为一个长寿命的交联，延迟或抑制系统的流动。在玻璃到橡胶的过渡区，网络链动力学负责，一个新的弛豫过程称为“慢模式”被清楚地检测到，特别是在介电谱。我们将这种松弛归因于轮烷型环糊精部分通过在聚合物主链上滑动伴随着链构象变化的旋转运动。讨论了慢模的可能机制及其与链段弛豫和链弛豫的关系。
We investigated the dynamics of the topological network formed by rotaxane-type movable crosslinks consisting of a poly(ethyl acrylate) backbone threaded through peracetylated cyclodextrins, which are connected to other chains. We used rheological and broadband dielectric spectroscopy measurements to analyze the dynamics on various time and length scales. The movable crosslink was found to affect the overall network dynamics in two different time scales. In the terminal region, it acted as a long-lived crosslink, delaying or inhibiting the flow of the system. In the glass-to-rubber transition region where network strand dynamics is responsible, a new relaxation process called “slow mode” was clearly detected, especially in dielectric spectroscopy. We ascribed this relaxation to the rotational motion of the rotaxane-type cyclodextrin moieties via sliding on the polymer backbone accompanied by the chain conformational change. A possible mechanism of the slow mode and its relationship with the segmental and chain relaxations are discussed.