Molecular interpretation of miscibility in polyamide‐6 blends with alkali ionomers of sulfonated polystyrene

Abstract

SYNOPSISBlends of polyamide-6 with lithium ionomers of 9.8 and 5.4 mole percent sulfonated polystyrene, formed by combining solutions of these polymers, are miscible over a wide compositional range, but those with the equivalent sodium ionomers are not. The molecular origin of this difference is addressed by studying the far infared and infrared spectra of the blends and pure materials to follow changes in the interactions between the cations and their surroundings, and changes in the interactions between functional groups. Based on analysis of these spectra, a molecular level interpretation of the blending is proposed. The initial step involves both the interaction of one amide carbonyl with an Li+ ion and simultaneous hydrogen bonding between an amide N -H and a sulfonate group. This eventually leads to formation of an Li(>CO)i(n -4) entity while the sulfonates are converted to the acid form through hydrogen bonding to the amide N -H groups. The Na+ ion does not interact strongly enough with the amide groups to leave its sulfonate environment to a significant extent. 0 1995 John Wiley & Sons, Inc.

Crystallization Inhibition in Solid Dispersions of MK‐0591 and Poly(vinylpyrrolidone) Polymers

“…23,24 Ionomers have also been found to affect the cyclic amide stretch of polyamides in binary blends as a result of the formation an ion-amide intermolecular complex. 25,26 These results can be compared with the indomethacin/PVP solid dispersions in which the Hbond interaction is stronger than that of the present ion-dipole interaction. 11,12 In this H-bonded system, as the polymer content increased, the carbonyl region reflected the transition from the dimerization of indomethacin to H-bonding between the drug and carbonyl group of the polymer.…”

When medical evidence alone is simply not enough

“…In this work, we extend our mechanicistic studies on the PET/MXD6 melt‐mixed blends. These blends have attracted scientific,30–35 technical,37 and commercial interest, in particular, in the area of food packaging because of their potential for combining the low O 2 and CO 2 permeability of the MXD6 (and order of magnitude higher than that of PET38–39) with the good toughness, clarity, and economics of PET. However, PET and MXD6 give incompatible blends with low optical clarity and an undesirable yellow color when processed in the molten state 40.…”

Compatibilization of Polymer Blends by Complexation. 1. Spectroscopic Characterization of Ion−Amide Interactions in Ionomer/Polyamide Blends

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