Molecular motion and material properties of cosoluble polymer blends

共溶聚合物聚苯乙烯（PS）和聚（乙烯基甲基醚）（PVME）的混合物瞬间变形，并测量应力松弛和双折射。由于两种聚合物的链段光学各向异性不同，可以从双折射来估计每种组分链段的变形程度。在长PS链和短PVME链共混的情况下，松弛模量表现出两个橡胶平台区。一是在短时间内且具有较高模量，这与两个聚合物组件的变形相关：该区域中的应力由系统中的所有聚合物链段支撑。然后，由于短PVME链失去变形效应，变得光学各向同性，一部分模量松弛。第二平台区域的应力完全由长PS链支撑，模量等于在低分子量普通溶剂中与共混物相同PS含量的PS溶液的模量。共混物中的PS链支撑；在短时间内比溶液中的链支撑更多的应力。显然由于 PS-PVME 缠结而产生的额外应力随着 PVME 失去变形效果而松弛。松弛速率不受 PS 长链分子量的影响。这些结果证实了聚合物链缠结的现代概念。

The blend of cosoluble polymers, polystyrene (PS) and poly(vinyl methyl ether), (PVME), was instantaneously deformed and the relaxation of stress and birefringence were measured. Owing to the difference of the segmental optical anisotropy of two polymers, one can estimate the degree of deformation of the segments of each component from the birefringence.In the case of the blend of long PS chains and short PVME chains, the relaxation modulus exhibited two rubbery plateau regions. One, at short times and with a higher modulus was corporated with the deformation of both polymer components: the stress in this region was supported by all the polymer segments in the system. A part of the modulus then relaxed as the short PVME chains lost the effect of deformation and became optically isotropic.The stress in the second plateau region was supported exclusively by the long PS chains and the modulus was equal to that of the PS solution, with the same PS content as the blend, in an ordinary solvent of low molecular weight.The PS chains in the blend supported;more stress at short times than the chains in the solution did. The extra stress, apparently due to the PS-PVME entanglement, relaxed as the PVME lost the effect of deformation. The rate of relaxation was not affected by the molecular weight of the long PS chains. These results substantiate the modern concept of the polymer chain entanglement.