The Miscibility of Hydrogen-Bonded Polymer Blends:  Two Self-Associating Polymers

Abstract

The factors that determine the miscibility of two polymers, each of which hydrogen bonds (self-associates) to itself in the pure state, is discussed. Equations describing the contributions of hydrogen bonding to the free energy of mixing are presented. It is shown that mixtures of this type are much less likely to be miscible than those where only one of the components self-associates, while the other has hydrogen-bonding acceptor groups. In addition, for mixtures of two self-associating polymers, the volume fraction of the hydrogen-bonding functional group relative to the volume of the polymer repeat unit is an important factor in determining miscibility. If this quantity differs significantly in the two polymers being mixed, even if they have identical hydrogen-bonding functional groups, the mixture will phase separate.

Estimation of Drug–Polymer Miscibility and Solubility in Amorphous Solid Dispersions Using Experimentally Determined Interaction Parameters

“…Miscible drug-polymer blends are also more resistant to drug crystallization than the amorphous drug alone (28,29), an important consideration when attempting to produce a drug delivery system that will perform consistently over time. Binary drugpolymer systems are usually deemed to be miscible if, after a given processing operation such as melt-extrusion, spray drying, or freeze drying, there exists a single glass transition temperature (30)(31)(32)(33)(34)(35)(36)(37)(38). However, the presence of a single glass transition temperature is not an infallible indicator of miscibility and provides no information about the thermodynamics of mixing.…”

“…Methods which provide quantitative information about the free energy of mixing two pharmaceutically relevant components such that drug-polymer compatibility can be predicted for a variety of temperatures and compositions are therefore of interest (39). While numerous theoretical and experimental approaches have been applied to understand polymer-polymer blending (30)(31)(32)35,36,(40)(41)(42)(43)(44), the thermodynamics of drug-polymer mixing is relatively unexplored.…”

Blends of Poly(4-Vinylpyridine) and Dihydric Phenols: Thermal and Infrared Spectroscopic Studies. Part Iii

“…Subsequently, a considerable interest arose for the chemical modification, such as graft copolymerization, as a way to improve the properties of the polymer materials. However, due to the high costs and environment pollution involved in the polymer synthesis processes, the study of polymer blends was notably developed in the last few decades [1][2][3][4][5][6] . These blends, by means of the simple mix of functionalized homo and copolymers, have been a very useful way to obtain new materials with novel properties [7][8][9][10] .…”

Miscibility of Blends of Biodegradable Polymers and Copolymers with Different Plasticizers

“…These potential donoracceptor specific interactions can lead to the formation of multicomponent complexes according to the following equilibrium processes: [24,[32][33][34][35][36][37] (i) self-association of plasticizer A molecules defined by a single equilibrium constant, s AA :…”

“…All of them are gathered in Table 1 and 3. The equilibrium constants have been selected among logical values, taking in mind the following remarks: (1) since no literature data is available for the associations between the polymers and the plasticizers used here, sets of simulations ranging from low to high density of intermolecular H-bonds have been tested; (2) it is normally considered that s AA ¼ s AB ¼ s AC, since the selfassociation ability of plasticizer is independent of the first link (AA, AB or AC); [32,35] (3) values of s ij > h AB are also very common for this type of systems; [33] (4) it has been assumed that the hydroxyl-carbonyl associations involve a much larger freeenergy change than other donoracceptor H-bonds, as pointed out by Painter et al [36] Miscibility of Blends of Biodegradable Polymers and . .…”