AbstractCertain mixtures of TFE/CHCl3were found to be excellent solvents for aliphatic polyamides such as nylon‐6, nylon‐66, nylon‐11, nylon‐12, nylon‐69, nylon‐610, and nylon‐612. Intrinsic viscosities were measured and Mark–Houwink coefficients determined for nylon‐6/TFE/CHCl3, indicating TFE‐rich mixtures to be better solvents than TFE alone. Similar results were obtained for TFE/CH2Cl2. Four ternary phase diagrams were constructed for nylon‐6/TFE/chloroalkanes, of which the ones with CHCl3and CH2Cl2are the most interesting. In the nylon‐6/TFE/CHCl3diagram higher nylon‐6 solubility in TFE‐rich mixtures and a biphasic region in the CHCl3‐rich compositions are evident. In the TFE/CH2Cl2system, the higher dissolution of nylon‐6 is observed, but no biphasic regions are detected. In certain solvent compositions and/or polymer concentrations the polymer is incompletely soluble, making the phase diagrams rather complicated. Observed thermodynamic excess properties appear to relate to the quality of TFE/chloroalkanes as solvents for nylon‐6. Studies on swelling of nylon‐6 networks immersed in TFE/CHCl3show a behaviour previously described by Krigbaum and Carpenter for a general case where the formation of contracts between molecules of the two solvents is discouraged and their preferential solvation of the polymer is, therefore, encouraged. The phenomena observed in this work can be qualitatively explained as arising from antagonistic interaction of TFE molecules with chloroalkane ones. The presence of the polyamides in solution reduces such contacts, enchancing the dissolution of the polymer
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