THE ROLE OF REPULSIVE INTERACTIONS IN POLYAMIDE BLENDS

Phase phenomena in mixtures containing any combination of aliphatic and aromatic polyamides can be formulated by the application of a mean‐field binary interaction model. This has been achieved by the quantitative analysis of the solubility of an aromatic polyamide, denoted as nylon 3Me6T, in a homologous series of aliphatic polyamides. A critical feature of this development required an estimation of the upper and lower bound concentration of methylene units of the latter for which the aromatic polyamide moved from a miscible to immiscible condition. The fabrication of random copolyamides of caprolactam‐laurolactam and 2‐pyrrolidinone‐caprolactam, respectively, has allowed an accurate determination of these critical limits. A survey of the behavior of polyamide blends will be discussed in light of this improved quantitative definition of the model. A principal feature of these analyses is the exclusion of a role for hydrogen bonding interactions. Details concerning the nature of interactions in these systems and how they are influenced by chemical structure are discussed. Copyright © 1990 Society of Plastics Engineers