DYNAMICS OF REVERSIBLY CROSS-LINKED CHAINS
DYNAMICS OF REVERSIBLY CROSS-LINKED CHAINS
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DOI：
10.1021/ma00194a076
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发表时间：
1989-04-01
期刊：
影响因子：
5.5
通讯作者：
BAXANDALL, LG
中科院分区：
文献类型：
--
作者：
BAXANDALL, LG
在平均场图中考虑了由可逆交联连接到（幻影）网络的聚合物链的动态和粘弹性响应。一个可逆的交联被假定为像一个经典的交联在绑定一段聚合物在空间中的一个固定点。然而，与总是保持完整的永久交联不同，可逆交联可以自发地脱离，然后重新附着以允许结合的片段和因此聚合物移动。这样一个绑定段的运动被视为熵控制，即，反弹段的位置的概率分布是适当的（本地）平衡。它示出了如何与这种动态的交联链表现出（自）diffusion和一个频谱的松弛过程。给出了扩散常数D与可逆交联数N及其沿着链分布的关系，并计算了哑铃型（N= 2）和喇叭型（N= 3）的弛豫谱。一般的线性链的松弛谱近似和动态的链与定期间隔的交联显示基本上是Rouse样的。
The dynamicsand viscoelastic response of a polymer chain bound by reversible cross-links to a (phantom) network are considered in a mean-field picture. A reversible cross-link is presumed to act like a classical cross-link in binding a segment of polymerto a fixed point in space. However, unlike the permanent cross-link which always remains intact, the reversible cross-link may spontaneously break away and then reattach to allow the bound segment and hence the polymer to move. The motion of such a bound segment is taken to be entropically controlled, ie, the probability distribution for the position of the rebound segment is that appropriate to (local) equilibrium. It is shown how chains with such dynamical cross-links exhibit (self-) diffusionand a spectrum of relaxation processes. The dependence of D, the diffusion constant, on the number of reversible cross-links, N, and their distribution along the chain is given and the relaxation spectra of the dumbbell (N= 2) and the trumbbell (N= 3) explicitly calculated. The relaxation spectrum of the general linear chain is approximated and the dynamics of a chain with regularly spaced cross-links shown to be essentially Rouse-like.