CREEP RATE SPECTROSCOPY

Laser-Interferometric Creep Rate Spectroscopy of Polymers... 

Creep Rate Spectroscopy for a Discrete Analysis of the Glass Transition Anomalies and Dynamic/Compositional Heterogeneity in Complex Polymer... 

In this survey, the novel Laser-Interferometric Creep Rate Meter (LICRM) setup and the original method of Creep Rate Spectroscopy (CRS) are described. We present the results of the numerous applications, in particular the new CRS possibilities as the high resolution method for the relaxation spectroscopy and thermal analysis of polymer systems. Furthermore, this method contributes to general progress in studying the deformation properties of polymers and other solids, especially at the micro- and submicrolevels. 

Using both gas and semiconductor lasers in the different modifications of these instruments, the new LICRM apparatus made it possible to develop a new way for the studies of relaxation dynamics and thermal characterization of polymers and other solids. This new method was later named the laser-interferometric Creep Rate Spectroscopy (CRS). The first publication on this topic appeared in 1984 [10], and the short survey of the earlier smdies, performed with the LICRM setup and the CRS technique, was published in 1994 [11]. 

Creep rate spectroscopy has been used for the discrete dynamic analysis of polymer networks such as PU network [19] PU-butyl methacrylate/dimethacrylate triethylene glycol copolymer interpenetrating networks (PU/BMA copolymer IPNs) [132, 133] commercial epoxy networks [134,135] the model epoxy-amine networks varying in crosslink density and rigidity [20] and the cross-linked hyperbranched polyimides [136],... 

Creep rate spectroscopy allowed us not only to estimate the dynamic heterogeneity but also to probe local (nanoscale) compositional inhomogeneity in the PU-BMA copolymer IPNs. For this purpose, the relative peak contributions to dynamics around Tg as a function of IPN composition were estimated. On this basis, the volume fractions of the nanodomains of neat constituent networks as well as their miscibility degree as a function of IPN composition could be determined, in a semi-quantitative way [133]. 

Creep rate spectroscopy study of the PCN-PTMG hybrid networks [148,151] demonstrated most distinctly the complicated, heterogeneous nature of glass transition dynamics in these systems providing the detailed information on this problem. Not only the dynamic heterogeneity (Tg plurality) but also the compositional heterogeneity and dynamics/nanostructure interrelationships were found for these amorphous networks. 

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