Evolution of concentration fluctuation during phase separation of polystyrene/poly(vinyl methyl ether) blend in the presence of nanosilica

Abstract

The influence of nanosilica on the concentration fluctuation of polystyrene/poly (vinyl methyl ether) (PS/PVME) mixtures was investigated during phase separation. The amplitude of concentration fluctuation was quantified by dielectric spectrums based on the idea of Lodge-Mcleish model and the linearized Cahn-Hilliard theory could describe the amplitude evolution of concentration fluctuation at the early stage of phase separation. Hydrophilic nanosilica A200 dispersed in PVME-rich phase behaved an obvious inhibition effect on the concentration fluctuation of blend matrix, while hydrophobic nanosilica R974 dispersed in PS-rich phase had little effect on the concentration fluctuation. The kinetics and amplitude evolution of concentration fluctuation during phase separation for PS/PVME/A200 nanocomposites were remarkably restrained due to the surface adsorption of PVME on A200. As the segmental dynamics of PVME and PS in homogeneous matrix was hardly influenced by A200 and R974, the enhanced miscibility and the significantly constrained flow relaxation of PVME chains might contribute to the retarded concentration fluctuation of PS/PVME/A200 nanocomposites. While the weak interaction between R974 and components of blend matrix and little effect of R974 on the molecular dynamics of PS chains may result in the weak retardation of concentration fluctuation for blend matrix.

Effect of grafted graphene nanosheets on morphology evolution and conductive behavior of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends during isothermal annealing

“…Therefore, the small effect of PMMA- g -RGO on the molecular dynamics of SAN chains might result in the weakened retardation of phase separation, in a similar fashion to the effect of weak retardation of hydrophobic silica R974 on the phase separation behavior of polystyrene/poly(vinyl ethyl ether) (PS/PVME) blends. 38,39 …”

“…Therefore, the small effect of PMMA-g-RGO on the molecular dynamics of SAN chains might result in the weakened retardation of phase separation, in a similar fashion to the effect of weak retardation of hydrophobic silica R974 on the phase separation behavior of polystyrene/poly(vinyl ethyl ether) (PS/PVME) blends. 38,39 Generally, the dispersion of nanoparticles in the molten polymer matrix is low in the thermodynamic equilibrium state, owing to a tendency to aggregate together to reduce excess interfacial energy. The driving force for the aggregation of llers might be the strong dispersive interaction between the ller and polymer matrix, and the depletion interaction between the adjacent nanoparticles.…”

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

“…Such stabilizing effect of HSNTs on the morphology of blend matrix can be also similar with that in spherical nanosilica lled systems and may be attributed to the conned chain motion due to the adsorption of chains on the surface of nanoparticles. 9,10,64,65 Furthermore, it can be found that some HSNTs aggregate in the PMMA-rich phase with the extending of annealing time and the diffusion motion of HSNTs in the phase-separated blend matrix should be mainly controlled by the mobility of PMMA surrounding HSNTs. 1 Here, there just exist a very small amount of relatively large aggregates of HSNTs in the PMMA-rich phase and we should explore whether the residual HSNTs form the ller network in the PMMA-rich phase to retard remarkably the SD phase separation of blend matrix in our next work.…”

“…Hence, the inuence of nanollers on the miscibility and phase separation for binary polymer blends should be explored to obtain the variation of morphology and microstructure for multicomponent systems. Partially miscible polymer blends are oen used as model systems to investigate their critical phase behaviors, such as lower critical solution temperature (LCST) blends [8][9][10] and upper critical solution temperature (UCST) blends. [11][12][13] In general, there are two types of phase separation mechanism upon variation in temperature, pressure or composition: nucleation and growth (NG) in the metastable region and spinodal decomposition (SD) in the unstable region.…”

“…[11][12][13] In general, there are two types of phase separation mechanism upon variation in temperature, pressure or composition: nucleation and growth (NG) in the metastable region and spinodal decomposition (SD) in the unstable region. [14][15][16][17] Extensive research has been mainly focused on the effect of spherical particles on the phase separation of polymer blends, for instance SiO 2 lled systems, such as polystyrene (PS)/poly(vinyl methyl ether) (PVME)/SiO 2 nanocomposites, 8,10,[18][19][20] poly(methyl methacrylate) (PMMA)/poly(styrene-co-acrylonitrile) (SAN)/SiO 2 nanocomposites, 9,[21][22][23] and polycarbonate (PC)/PMMA/SiO 2 nanocomposites. 24 The inuence of nanollers with other topological shapes on the phase separation of blend matrix has been also reported for one or two dimensional nanollers lled systems, such as PS/PVME/multiwall carbon nanotubes (MWCNTs) nanocomposites, [25][26][27] PMMA/SAN/MWCNTs nanocomposites, 1,28,29 PMMA/SAN/clay nanocomposites, 30,31 PMMA/ SAN/GO nanocomposites, 32 PMMA/SAN/chemically reduced graphene oxide (CRGO) nanocomposites 33,34 and PS/PVME/reduced graphene oxide (RGO) nanocomposites.…”