Post‐nylon polyamides

Synthesis and Properties of Hyperbranched Aromatic Polyamide

“…Aromatic polyamides (aramids), such as poly( p -phenyleneterephthalamide), are well-known as high-performance polymers due to their excellent thermal, mechanical, and chemical properties. Aramid fibers, prepared by liquid crystal spinning, and films have a large number of applications in modern industries. − Aromatic polyamides can be readily synthesized by low-temperature polycondensation of diacid chlorides and diamines , and, alternatively, by direct polycondensation of diacids and diamines in the presence of condensing agents such as triphenyl phosphite and pyridine . These polymers, however, are only soluble in highly polar solvents such as concentrated sulfuric acid.…”

Successful Thermal Self-Polycondensation of AB2 Monomer to Form Hyperbranched Aromatic Polyamide

“…Aromatic polyamides are well-known as high performance polymers due to their excellent thermal, mechanical and chemical properties. − There are two conventional methods for the synthesis of aromatic polyamides. One is a low-temperature solution polymerization, where diacid chlorides are reacted with aromatic diamines to form polyamides. , The other is a direct polycondensation of aromatic diacids and diamines in the presence of condensing agents. − Although thermal polymerization is a well-known industrial process for aliphatic polyamides with a high molecular weight, it is very difficult to obtain aromatic polyamides having a high molecular weight by the molten polycondensation method. , This has been mainly explained by the lower reactivity of aromatic amines compared with that of aliphatic amines because of the resonance effect of phenyl groups. The high reaction temperatures usually result in extensive side reactions that restrict polymer molecular weight.…”

Effect of amide distribution in polyamide isomers on their melting points

“…The set of data from Table , used for obtaining a fit with minimized least square sum of deviations, is limited to K ≥ 4. This choice is made because PA with K = 0 based on hydrazine have a limited thermal stability, degrading at low temperatures to form a polyaminotriazole groups . PA with K = 0 based on oxalic acid (PA X.2) are known to the authors .…”

“…This choice is made because PA with K 5 0 based on hydrazine have a limited thermal stability, degrading at low temperatures to form a polyaminotriazole groups. 13 PA with K 5 0 based on oxalic acid (PA X.2) are known to the authors. 8 PA with K 5 2 based on succinic acid have a limited thermal stability 1 degrading to succinimide groups.…”