Effect of amide distribution in polyamide isomers on their melting points

Abstract

A new insight has been obtained relating the different structures of linear aliphatic homopolyamides to their melting points. A new equation is derived for structures based on monomers with an even number of methylene units. In this equation, the amide distribution along the polymer chain is defined by a newly introduced parameter K which indicates the lowest number of methylene units between adjacent amide groups. For K ≥ 4 a generic empirical relation is defined, describing the observed melting points of these polyamides. The trend in H‐bond densities in the melt obtained by modeling corresponds well with the trend in observed melting points. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45837.