Polyesteramide

Polyesteramide is a class of polymeric materials that combines features of both polyester and polyamide (nylon) chemistries. The term refers to copolymers in which ester linkages, found in polyesters, and amide linkages, characteristic of polyamides, coexist within the same macromolecular chain. The most common polyesteramide blend is obtained through the polycondensation of terephthalic acid (a diterephthalic acid precursor) and hexamethylenediamine, producing a material that exhibits both the crystalline strength of nylon and the reduced moisture absorption of polyester.

The synthesis of polyesteramides typically involves a step‑condensation reaction under conditions that favor both esterification and amidation. Reaction temperatures are carefully controlled to minimize the competing transesterification reaction and to achieve the desired degree of polymerization. Post‑polymerization treatments, such as melt extrusion or solution casting, are used to form fibers or films.

Key properties of polyesteramides include high tensile strength, good abrasion resistance, and a lower coefficient of friction compared to pure polyesters. Compared with polyamides, polyesteramides often exhibit improved dimensional stability and resistance to hydrolytic scission at elevated temperatures. Their morphology can be tailored through the ratio of ester to amide units, influencing crystallinity and melting temperature.

Applications of polyesteramides span the textile, automotive, and engineering sectors. In fashion, they are used for warp knit fabrics and technical apparel that require durability and low moisture regain. Automotive applications include interior trim components, harnesses, and connecting rods, where the material’s balance of thermal stability and mechanical robustness is advantageous. The growing interest in sustainable polymers has also sparked research into bio‑based polyesteramides derived from renewable monomers.