New Precursors for Polyamide Synthesis
Polimery 1997, No 6, 361
A newroute to polyamides [AABB]n involving polyamidation of difunctional monoamideshas been studied. The process is based on the synthesis of an a-amino ω-ester monoamide precursor (AME-n,p) easily available by making adiamine to react with a dimethyl diester in the bulk at a rather lowtemperature preferably in the presence of a phenol derivative. In suchconditions, AME-n,p precipitates with a very good yield (90—95%). One of thegreatest advantages of AME-n,p is to keep the stoichiometric balance forfurther polyamidation; that is not evident in many other processes. For thevery important case of polyamide-6,6 synthesis, we showed that the relative precursorAME-6,6 is easily available and also very stable, even if stored e.g. in air at room temperature for 50 days. Polyamides-6 ,6 have been obtained from AME-6 ,6 (used freshly, prepared orafter storage) in laboratory glass reactors by direct heating under vacuum(270°C) with number-average molar masses of roughly 20,000.