Toughened and hydrophobically modified polyamide 11 copolymers with dimer acids derived from waste vegetable oil

ABSTRACT 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. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47174.