Interrelations between Rheology and Phase Behaviour in Partially Miscible Blends: The Case of Polydimethylsiloxane/Polyethylmethylsiloxane (PDMS/PEMS)

Abstract

A rheological study of the phase behaviour and the dynamics in the immiscible region of a model partially miscible Upper Critical Solution Temperature (UCST) blend was carried out by using a series of nearly monodisperse polydimethylsiloxane (PDMS) of varying molecular weights blended with polyethylmethylsiloxane (PEMS). The complete phase diagram was established through steady shear rheology, optical microscopy and light scattering. The UCST, interfacial tension and morphology of these blends are very sensitive to the molecular weight of the constituents. Partial miscibility was observed only when the Mw of PDMS was sufficiently low. The viscoelastic behaviour in the phase separated region can be modeled successfully using the Palierne model.

Phase behavior of polyethylene/ethylene vinyl acetate blends: Studies on miscibility window, composition dependency of interfacial interactions, and enhanced toughness

“…Therefore, concurrent effect of these two cannot provide an abrupt change in moduli such as the one observed in LCST counterparts. Thus, following the work of other researchers, 21–23 the temperature, wherein a change in the G ′-temperature slope was observed, was assigned to the binodal temperature.…”

Thermodynamics of Poly(dimethylsiloxane)/Poly(ethylmethylsiloxane) (PDMS/PEMS) Blends in the Presence of High-Pressure CO2

“…In some cases, it can be expected that the influence of some of these variables is relatively negligible. Several independent studies 19,22,23 of PDMS/PEMS blends have, for example, shown that χ is independent of blend composition. An exception to these findings is the work of Meier et al, 24 who provide evidence for the composition dependence of χ.…”

“…Because of the low T g of these polymers (typically between -150 and -120 °C), 17 their blends are molten at relatively low temperatures, including ambient temperature and above. Several studies have reported on the phase [18][19][20][21][22][23] and critical [24][25][26][27] behavior of, as well as interdiffusion 28 in, PDMS/PEMS blends in the absence of CO 2 , thereby providing a solid baseline from which to proceed. Various strategies 19,22,24 have been used in an attempt to discern interaction parameters for this blend, and a summary of these previous activities is provided in Table 1.…”

Thermoplastic self‐healing polymer blends for structural composites: Development of polyamide 6 and cyclic olefinic copolymer blends

“…55 Through the Han plot, the compatibility of a polymer blend can be confirmed if the plotted curves are characterized by the same slope at different relative concentrations of the constituents. 56,57 On the other hand, if these curves are not characterized by the same slope, the analyzed blend is considered to be immiscible. 58,59 The Cole-Cole plots of the neat matrices and their blends are reported in Figure 3a.…”