Effect of interfacial interactions on static and dynamic behavior of hyperbranched polymers: Comparison between different layered nanoadditives

The structure and dynamics of a hyperbranched poly (ester amide) and its nanocomposites with natural sodium montmorillonite (Na+-MMT) and graphite oxide (GO) are investigated to provide an understanding of the influence of different polymer-inorganic interfacial interactions on the polymer behavior. In both systems, the favorable interactions lead to intercalated structures; however, the different interaction strengths create polymer nanofilms of different thicknesses between the inorganic layers. The composition of the nanohybrids is such that all chains are expected to reside within the galleries of the nanoadditives. Thermal reduction of GO in the presence of the polymer forces the system to lose its periodic structure; nevertheless, the deoxygenation temperature decreases in the presence of the polymer when compared to the respective one for the bare GO. At the same time, the thermal stability of the polymer decreases in the presence of GO. In both cases, the glass transition of the intercalated chains is fully suppressed. The different surface interactions affect polymer dynamics by modifying the number of relaxation processes, their relaxation times which become faster or slower than the bulk, as well as the temperature dependencies of the processes.