Local Chain Deformation and Overstrain in Reinforced Elastomers: An NMR Study
Local Chain Deformation and Overstrain in Reinforced Elastomers: An NMR Study
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DOI：
10.1021/ma400921k
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发表时间：
2013-07-23
期刊：
影响因子：
5.5
通讯作者：
Ott, Maria
中科院分区：
文献类型：
--
作者：
Perez-Aparicio, Roberto;Schiewek, Martin;Ott, Maria
从分子水平理解弹性体的应变响应是将微观动力学与宏观特性联系起来的关键。在这项研究中，我们调查的局部应变响应的硫化，天然橡胶系统和纳米尺寸的填料颗粒，这是已知的，导致高度改善的机械性能的影响。多量子NMR方法能够分离相对低分数的网络缺陷，并允许定量和选择性地研究在微观（分子）尺度上的应变网络矩阵中的局部变形分布。我们发现，不变形的填料颗粒的存在下诱导增强的局部变形的矩阵（通常被称为过度应变），局部应力/应变的不均匀性略有增加，和各向异性降低。此外，仔细分析的小非弹性缺陷分数提供了新的证据，以前的NMR和散射结果的应变缺陷丰富的弹性体不能解释没有明确考虑到非弹性缺陷分数。
A molecular-level understanding of the strain response of elastomers is a key to connect microscopic dynamics to macroscopic properties. In this study we investigate the local strain response of vulcanized, natural rubber systems and the effect of nanometer-sized filler particles, which are known to lead to highly improved mechanical properties. A multiple-quantum NMR approach enables the separation of relatively low fractions of network defects and allows to quantitatively and selectively study the local deformation distribution in the strained networks matrix on the microscopic (molecular) scale. We find that the presence of nondeformable filler particles induces an enhanced local deformation of the matrix (commonly referred to as overstrain), a slightly increased local stress/strain heterogeneity, and a reduced anisotropy. Furthermore, a careful analysis of the small nonelastic defect fraction provides new evidence that previous NMR and scattering results of strained defect-rich elastomers cannot be interpreted without explicitly taking the nonelastic defect fraction into account.