Phase miscibility and dynamic heterogeneity in PMMA/SAN blends through solvent free reactive grafting of SAN on graphene oxide

Miscibility and Phase Separation in PMMA/SAN Blends Investigated by Nanoscale AFM-IR

The miscibility and phase separation of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile (SAN) have already been investigated using various methods. However, these methods have limitations that often result in inconsistent characterization. Consequently, the reasons for the dependence of miscibility on composition as well as on processing temperature have not yet been proved. The phase separation of PMMA/SAN blends was therefore investigated for the first time using a novel technique, nanoscale AFM-IR. It couples nanoscale atomic force microscopy (AFM) with infrared (IR) spectroscopy. Therefore, the phase morphology can be chemically identified and precisely classified within the nm-regime. The PMMA/SAN blends, on the other hand, were analyzed of their changes in morphology under different thermal treatments. It was possible to visualize and define the phase separation, as well as dependence of the miscibility on the mixing ratio. In the miscible domain, no two individual phases could be detected down to the nanometer range. It was shown that with increasing temperature, the morphology changes and two different phases are formed, where the phase boundaries can be sharply defined. The onset of these changes could be identified at temperatures of about 100 °C.

Nanoparticles influence miscibility in LCST polymer blends: from fundamental perspective to current applications

Polymer blending is an effective method that can be used to fabricate new versatile materials with enhanced properties. The blending of two polymers can result in either a miscible or an immiscible polymer blend system. This present review provides an in-depth summary of the miscibility of LCST polymer blend systems, an area that has garnered much attention in the past few years. The initial discourse of the present review mainly focuses on process-induced changes in the miscibility of polymer blend systems, and how the preparation of polymer blends affects their final properties. This review further highlights how nanoparticles induce miscibility and describes the various methods that can be implemented to avoid nanoparticle aggregation. The concepts and different state-of-the-art experimental methods which can be used to determine miscibility in polymer blends are also highlighted. Lastly, the importance of studying miscible polymer blends is extensively explored by looking at their importance in barrier materials, EMI shielding, corrosion protection, light-emitting diodes, gas separation, and lithium battery applications. The primary goal of this review is to cover the journey from the fundamental aspects of miscible polymer blends to their applications.

Phase separation behavior of poly(methyl methacrylate)/poly(styrene-co-maleic anhydride) in the presence of hollow silica nanotubes

The phase separation behavior of poly(methyl methacrylate) (PMMA)/poly(styrene-co-maleic anhydride) (SMA) blends with and without one-dimensional hollow silica nanotubes (HSNTs) was investigated using time-resolved small-angle laser light scattering. During isothermal annealing over a range of 100 °C above the glass transition temperature, the Arrhenius equation is applicable to describe the temperature dependence of phase separation behavior at the early and late stages of spinodal decomposition (SD) for unfilled and filled PMMA/SMA systems. The mechanical barrier effect of HSNTs on the macromolecular chain diffusion of the blend matrix may retard the concentration fluctuation at the early stage and slow down the domain coarsening at the late stage of SD phase separation for the blend matrix to result in the decrease of apparent diffusion coefficient D_app, the postponement of the relaxation time and the decline of temperature sensitivity for the phase separation rate.

The applicability of Arrhenius equation to the phase separation behaviors for filled systems indicates that HSNTs results in the decline of temperature sensitivity for phase separation rate, but hardly changes the viscous diffusion essence of chains.