Interaction energies for blends of poly(methyl methacrylate), polystyrene, and poly(.alpha.-methylstyrene) by the critical molecular weight method

Abstract

Interaction energies for each of the binary pairs PS/Pa-MS, PS/PMMA, and PMMA/Pa-MS were calculated by fitting spinodal curves predicted by the Flory-Huggins theory and the Sanchez-Lacombe equation of state theory to experimental cloud point data for blends of low molecular weight polymers. For blends of PS and -MS, where cloud points could not be observed, the molecular weight limit of miscibility was used to bracket the interaction energy. Phase separation boundaries for this system were predicted to be caused by UCST-type behavior. Oligomeric blends of PMMA with PS showed UCST-type phase boundaries while blends of PMMA with -MS showed LCST-type boundaries. The mechanism of phase separation boundaries was found to stem from the differences between the characteristic temperatures for the pure components (AT*). End groups on the oligomeric homopolymers significantly affect the calculated interaction energies, and corrections for this were made by three methods including a binary interaction model analysis.

Investigation of the Effects of Isotopic Labeling at a PS/PMMA Interface Using SIMS and Mean-Field Theory

“…6,33 The temperature dependency of the dPS segregation was tested for system B at temperatures ranging Because an -OH group, such as that at the end of the dPS-OH is known to hydrogen bond with P2VP much more strongly than with PMMA the negligible dPS-OH excess at the hPS:dPS-OH/P2VP interface (vertical line) further supports that unwanted end-functional groups on the dPS-130 are not the underlying cause of the dPS segregation shown in Figure 1. The interface is set to 0, and the depth is scaled to the statistical segment length (a) of hPS and dPS.…”

Novel Miscible Blends Composed of Poly(Methyl Methacrylate) and 2,2-Bis(3,4-Carboxyphenyl)Hexafluoropropane Dianhydride-Based Polyimides with Optical Grade Clarity

“…Different solvents with different casting temperatures were used in each method in order to prevent erroneous judgment about miscibility stemming from the so-called solvent effect. 25,26) In S1, the blend was prepared in film form by casting solutions containing 5 mass% tetrahydrofuran (THF) onto petri dishes at 60 C. After slow drying at 80 C for a day, the blends were dried in a vacuum oven at 150 C for a week. S2 followed the same procedure as S1, except that the solvent was methylene chloride (MC) and was evaporated at room temperature.…”

“…The immiscibility of ternary solvent/polymer/ polymer mixtures is induced by the asymmetry of binary interactions or the so-called Á effects. 25,32,33) This implies that a miscible polymer-polymer mixture can be made immiscible by using a solvent during the preparation of the polymer samples. Therefore, in this study, the samples prepared by three different methods show different miscibilities.…”

“…In this study, the scratch resistance was measured using the traditional pencil test. 25) Please note that other mechanical properties were not measured in this study because it is beyond the scope of this paper to explore the specific measurements of the mechanical properties. More detailed studies will report on these in the future.…”

“…25,26) In this study, blend samples were prepared by solvent casting. Because the miscibility of the blends examined here was sensitive to preparation methods, various solvent casting methods were used for the preparation of the blend samples.…”