Independent Observation of the Two Relaxations in Chain Anisotropy and in Entanglement Network of Condensed Polymers under Large Deformations

大变形下稠合聚合物链各向异性和缠结网络的两次弛豫的独立观测

• 批准号: 10450363
• 负责人: ISONO Yoshinobu
• 金额: $ 3.97万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-10450363/
• 关键词: Condensed Polymers; Nonlinear Viscoelasticity; Large Deformation; Entanglement; Rubbery Plateau; Dynamic Modulus; Nonequilibrium Structure; Relaxation Time

Viscoelastic properties of well-entangled polymers can be expressed by two parameters, e.g., the plateau modulus and the longest relaxation time even outside the range of linear viscoelasticity. The former, a measure of the entanglement network, can be given by measurements of differential dynamic modulus by means of small oscillatory deformations superposed on a large deformation. There has been found the correspondence between nonlinear viscoelasticity and change in entanglement network. The network shows no change in linear viscoelasticity. In a large deformation, however, it really changes with the strain given to the material.Many investigators have been believed that viscoelastic properties of polymers are due to chain anisotropy and can be understood with strain-dependent memory function obtained by stress decay. The theory using reptation concept and tube-model is based on the way of thinking, too. It may be true for polymer dilute system. In considering polymer condensed syste … More m where intermolecular entanglement exists, however, we should take not only chain anisotropy but also change and recovery of entanglement network into consideration. The former and the latter are reflected in the changes in refractive index tensor and the height of rubbery plateau, respectively. Hence we can discuss the nonlinear viscoelasticity from the independent and concurrent measurements of birefringence and differential dynamic modulus. In this work, we have constructed a novel biaxial rheometer equipped with an optical train for birefringence and progressed the measurements. From the independent measurements of the two relaxations in the chain anisotropy and in the entanglement network structure, it was found that the entanglement network ruptured by large deformation takes a very long time to recover to the equlibrium one. The entanglement network does not recover even after the chain configuration relaxes completely. The change in entanglement network is found to play an essential role in nonlinear viscoelastic response. Less

良好缠结的聚合物的粘弹性可以由两个参数表示，例如，平台模量和最长的松弛时间，甚至在线性粘弹性的范围之外。前者是缠结网络的一种度量，可以通过叠加在大变形上的小振荡变形的微分动态模量的测量来给出。发现了非线性粘弹性与缠结网络变化之间的对应关系。网络的线性粘弹性没有变化。许多研究者认为聚合物的粘弹性是由链的各向异性引起的，可以用应力衰减得到的应变相关记忆函数来理解。爬行概念和管道模型的理论也是基于这种思维方式。对于聚合物稀相体系，可能是这样。在考虑聚合物凝聚体系时， ...更多信息 在存在分子间纠缠的情况下，不仅要考虑链的各向异性，还要考虑纠缠网络的变化和恢复。前者和后者分别反映在折射率张量和橡胶态平台高度的变化上。因此，我们可以从双折射和微分动态模量的独立测量和同时测量来讨论非线性粘弹性。在这项工作中，我们已经建立了一个新的双轴流变仪配备了一个光学列车的双折射和进展的测量。通过对链各向异性和纠缠网络结构中两种弛豫的独立测量，发现大变形破坏的纠缠网络需要很长的时间才能恢复到平衡状态。即使在链结构完全松弛后，纠缠网络也不会恢复。纠缠网络的变化被发现在非线性粘弹性响应中起着至关重要的作用。少

项目成果

Yoshinobu Isono: "Relaxation of stress and recovery of entanglement network structure"AIP Conference Proceedings on Slow Dynamics in Complex Systems. 469. 639-640 (1999)

Yoshinobu Isono：“应力松弛与纠缠网络结构恢复”AIP 复杂系统慢动力学会议论文集。

Isono, Yoshinobu, Kawahara, Seiichi: "Differential Dynamic Modulus of Silica Filled and Carbon Black Filled SBR Vulcanizates in Cycles of Large Shearing Deformation and Recovery"Rubber Chemistry and Technology. (in press).

Isono、Yoshinobu、Kawahara、Seiichi：“二氧化硅填充和炭黑填充 SBR 硫化胶在大剪切变形和恢复循环中的动态模量差异”橡胶化学与技术。

SeiicHi Kawahara,Yoshinobu Isono et al.: "Crystallization behavior and strength of natural rubber:skim rubber,deprotenized natural rubber,and pale clepe"Journal of Applied Polymer Science. 78・10. 1510-1516 (2000)

SeiicHi Kawahara、Yoshinobu Isono 等：“天然橡胶的结晶行为和强度：脱脂橡胶、脱质天然橡胶和苍白橡胶”应用高分子科学杂志 78・10（2000 年）。

Isono, Yoshinobu: "Relaxation of Stress and Recovery of Entanglement Network Structure"AIP Conference Proceedings 469, "Slow Dynamics in Complex Systems". 639-640 (1999)

Isono, Yoshinobu：“应力的松弛和纠缠网络结构的恢复”AIP 会议论文集 469，“复杂系统中的慢速动力学”。

Yoshinobu Isono,Seiichi Kawahara et al.: "Differential dynamic modulus of silica filled and carbon black filled SBR vulcanizates in cycles of large shearing deformation and recovery"Rubber Chemistry and Technology. (In press).

Yoshinobu Isono、Seiichi Kawahara 等人：“大剪切变形和恢复循环中二氧化硅填充和炭黑填充的 SBR 硫化胶的动态模量差异”《橡胶化学与技术》。