Polymer-polymer interactions via analog calorimetry. 2. Blends of polystyrene with bisphenol-A polycarbonate and tetramethyl bisphenol-A polycarbonate

Abstract

Analog calorimetry is used as a tool to study the interaction of polystyrene, PS, with bisphenol‐A polycarbonate, PC, and with tetramethyl bisphenol‐A polycarbonate, TMPC. Electrostatic charge calculations were used as a guide to divide polymer repeat units and analogs into groups. A mean‐field binary interaction model was used to evaluate group interaction energies. The enthalpic interaction energy obtained from this study for the PS‐PC pair is 0.41 ± 0.13 cal/cm3 while that for the PS‐TMPC pair is 0.19 ± 0.34 cal/cm3. The result for PS‐PC blends is in good agreement with values obtained from studies using the critical molecular weight approach and the phase behavior of copolymer blends. The value for PS‐TMPC does not correctly predict the phase behavior of this blend; however, its standard deviation (on both an absolute and relative basis) is large and the range of possible interaction energies includes the negative values obtained from neutron scattering. The results of this study indicate that the presence of methyl groups on the aromatic ring of TMPC repeat unit is the main factor favoring the miscibility of PS‐TMPC blends. © 1997 John Wiley & Sons, Inc.

Binary Interaction Energy Densities for Blends of Styrene/Acrylonitrile Copolymers with Methyl Methacrylate/n-Alkyl Acrylate Copolymers

“…Thus, the k ij calculated from eq 12 includes both enthalpic and entropic terms. The enthalpic contribution to k ij for several interaction pairs were computed from the heat of mixing data previously determined in this laboratory via analogue calorimetry experiments. − These calculations show that the enthalpic term dominates. Therefore, in the following discussion, the entropic contribution will be neglected as we examine the deviation of the geometric mean assumption in terms of differences in molecular characteristics between repeat units.…”

Effects of Fluctuations and Compressibility on the Phase Behavior of Loop-Forming Diblock Copolymers

“…Even a weak directional interaction put into the system was shown to still cause self-assembly because the combinatorial entropy scales as 1/ N . , It is difficult in the present approach to reveal the precise description of specific interactions involved. However, one might conjecture from Ziaee and Paul's work − on the blends containing PS that the electron density distribution of styrene around the phenyl ring and the polar ester group of PA 5 MA are possible contributors to such specific interactions. To verify this speculation, some spectroscopic methods such as Raman or IR spectroscopy are required to scrutinize the behavior of suspicious groups.…”

Generalized Flory-Huggins model for heat-of-mixing and phase-behavior calculations of polymer-polymer mixtures

“…(4) and (5), it is evident that the original FH theory gives an enthalpy of mixing which is independent of temperature. Experimental results for various mixtures show that this is not generally true and Δ H mix must be a function of temperature 26–31…”