Broadband Dielectric Spectroscopy (BDS) and Differential Scanning Calorimetry (DSC) are employed to study molecular dynamics and glass transition temperature (Tg) in poly(methyl methacrylate) (PMMA)/Silica-nanoparticle (NP) composites. By systematically probing the case of bare (non-functionalized) Si-NPs dispersed in PMMA matrix and that of PMMA grafted Si-NPs in PMMA matrix, we isolate the effects of each of these cases on dynamics and Tg. Furthermore, we show - for the structural relaxation process - that in addition to slowed down mobility, which is commonly reported in literature and assigned to dynamics at the NP-matrix interface, faster modes also arise due to confinement effects. Scanning Electron Microscopy (SEM) is used to confirm uniform dispersion of the NPs.E.M., and J.S. acknowledge support from the National Science Foundation, Division of Materials Research, Polymers Program, award DMR-1508394.
APS March Meeting Abstracts
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