A series of dimer acid (DA)-modified polyamide 11 copolymers is synthesized via melt polycondensation from 11-aminoundecanoic acid, hexamethylene diamine (HMDA), and DA, prepared by the hydrolysis of waste vegetable oil and a subsequent Diels-Alder reaction. The molecular structures and the polymers' molar masses are characterized by nuclear magnetic resonance, Fourier-transform infrared spectroscopy, size exclusion chromatography. The thermal and mechanical properties are modified with increasing the composition of DA in PA copolymers by increasing the chain irregularity of the PA, thereby reducing the hydrogen bonding strength of the amide groups. Finally, water contact angle and water absorption experiments show that the hydrophobicity of DA-modified PA copolymers is increased as compared to neat PA11. As a result, these thermoplastic materials could offer improved sustainability and performances by the addition of renewable DA monomer in PA copolymers.

A series of polyester copolymers was synthesized via melt polycondensation of dimethyl terephthalate (DMT), dimethyl isophthalate (DMI), and 1,4-butanediol (BDO) with dimer acid methyl ester (DAME) monomers, previously prepared by the Diels-Alder reaction of fatty acid methyl esters (FAMEs). We obtained copolymers with the desired composition and a high molar mass characterized by 1 H NMR, FT-IR, and SEC. The relationship among the composition, thermal behavior, mechanical properties, and adhesion properties of these copolymers was examined, demonstrating that the DAME-modified copolymers could be substituted for HMA applications and are comparable to petroleum-based commercial products. As a result, these polyesters could offer improved sustainability and performance and may be good candidates for hot-melt adhesive materials.