Macromolecular compounds Communication 69. Dependence of the properties of polyamides on the extent of intermolecular hydrogen bonding

Abstract

1. A number of mixed polyamides have been investigated from the point of view of the effect of hydrogen bonds on the properties of polyamides, and it has been shown that owing to steric hindrance a considerable proportion of the amide groupings cannot interact through hydrogen bonds, this fact being reflected in all of the physical properties of the polymer. 2. The properties of mixed polyamide systems have been studied, the substances investigated being products of the reaction of 1,6-hexanediamine with a mixture of two dicarboxylic acids, selected from adipic, succinic, suberic, azelaic, and sebacic acids. 3. It has been shown that for polyamides derived from a given dicarboxylic acid and various diamines, the melting point varies with the number of carbon atoms in the diamine in accordance with a zig-zag curve the melting point being higher when the number is even than when it is odd. 4. It has been found that the melting points of polyamides derived from dicarboxylic acids having even numbers of carbon atoms in their molecules vary linearly with the number of amide groupings (i.e. hydrogen bonds). 5. A graphical method has been proposed for the determination of the extent of intermolecular hydrogen bonding in mixed polyamides.