Phase separation dynamics of a poly(vinyl methyl ether)/polystyrene (PVME/PS) blend studied by ultrafast differential scanning calorimetry

Abstract

In this work, ultrafast differential scanning calorimetry (UFDSC) is used to study the dynamics of phase separation. Taking poly(vinyl methyl ether)/polystyrene (PVME/PS) blend as the example, we firstly obtained the phase diagram that has lower critical solution temperature (LCST), together with the glass transition temperature (Tg) of the homogeneous blend with different composition. Then, the dynamics of the phase separation of the PVME/PS blend with a mass ratio of 7:3 was studied in the time range from milliseconds to hours, by the virtue of small time and spatial resolution that UFDSC offers. The time dependence of the glass transition temperature (Tg) of PVME‐rich phase, shows a distinct change when the annealing temperature (Ta) changes from below to above 385 K. This corresponds to the transition from the nucleation and growth (NG) mechanism to the spinodal decomposition (SD) mechanism, as was verified by morphological and rheometric investigations. For the SD mechanism, the temperature‐dependent composition evolution in PVME‐rich domain was found to follow the Williams–Landel–Ferry (WLF) laws. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1357–1364

Quantitative determination of the spring entropy effect and its indication of the conformational change of polymer coils with varying concentration in aqueous poly(N-isopropylamide) solutions

“…Moreover, due to the limitations in the heating and cooling scan rate of conventional DSC method, although a relative high cooling rate applied in this investigation, the macroscopic DSC experiment can only observe the demixing phenomenon in a long time scale. Although ultrafast DSC (the so-called ash DSC) can be utilized to investigate the inuence of fast cooling and heating on the dynamic phenomena in homopolymer and polymer blends, 71 this stage it can only be used to test solid samples. In contrast, laser temperature-jump time-resolved technique combined with other microscopic probing method can obtain the demixing information in a millisecond scale, 73 which could help us in obtaining more comprehensive results on the aggregation behavior of polymer above LCST temperature.…”

Glass Transition Phenomenon for Conjugated Polymers

“…However, the sample preparation is time consuming since it requires the stacking of several hundred layers of ultrathin film in order to meet the mass requirement . With the new developments of the nanocalorimetry, including flash DSC and AC‐chip calorimetry (We note here that the modulated DSC and the AC‐chip calorimetry are considered as dynamic measurements of T g ), which has the mass requirement of nanogram, measuring the T g of sub‐100 nm a single layer of polymer ultrathin film with DSC becomes possible and has drawn increasing attention …”

Thermodynamic analysis of the phase equilibrium of the polystyrene‐poly(vinyl methyl ether) system

“…However, these data contradict the results of the subsequent studies. 23,25 The research into this system has been actively continued in the last 20 years [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] with the involvement of modern local structural and morphological methods such us fourier-transform infrared spectroscopy (FTIR), 36 small-angle neutron scattering (SANS), 37 Ultrafast differential scanning calorimetry (DSC), 39,41 and other. At the same time, the emphasis has shifted from phase diagrams to the analysis of the features of phase separation, 33,34,38,43 the influence of such external factors as pressure, 36 the effect of changes in the terminal groups of components, [30][31][32] their crosslinking, including hydrogen bonds, 29,35 and the dynamics of nanoparticles.…”