Abstract
We analyze recent deuterium NMR data on blends of poly(ethylene oxide) (PEO) with poly(methyl methacrylate) (PMMA), using a model for the blend dynamics based on the coupling model. This model has previously been shown to describe the relaxation properties of blends whose component dynamics are strongly composition dependent. We show herein that the unusual feature of PEO/PMMA blends, an invariance of the PEO dynamics to composition, is a natural consequence of the high frequency and temperature of the NMR experiments. To wit, when the independent relaxation time of our model approaches the characteristic time for intermolecular cooperativity (∼2 ps), the effect of local environment on the component dynamics becomes negligible. A similar situation pertains for poly(vinyl methyl ether) mixed with polystyrene, at temperatures sufficiently high that the segmental relaxation times become small. On the other hand, for blends of 1,4-polyisoprene with poly(vinylethylene), the component dynamics retain their dependence on composition, even at high temperatures. The reason for the differing behavior is brought out by an analysis using our blend model.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
