Synthesis of biobased polyamides for hot melt adhesives: Utilizing renewable dimer acids and 1,5-pentanediamine monomers

Biobased polyamides (BPAs) are increasingly attractive alternatives to conventional petroleum-derived polymers, owing to their bio-renewable and environmentally friendly. Nonetheless, their practical applications are severely restricted by excessive prices, limited scalability, and poor mechanical-thermal properties. Herein, a series of copolyamides (COPAs) were successfully synthesized by the one-pot polycondensation using sebacic acid-1,10-decane-diamine salt, biobased dimer acid, and biobased 1,5-pentanediamine monomers as raw materials. The thermal analysis revealed that the COPAs exhibited high thermal stability and suitable melting points with a Tm of 71-152 degrees C. The processing properties and strong tensile strength were enhanced up to 24 MPa. Thus, as hot melt adhesives, the COPA30 demonstrated an adhesion strength of 8.28 MPa, making them suitable for various substrates such as aluminum, wood and iron. Notably, the COPA50 only slightly swelled after being immersed in organic solutions at room temperature for 30 days, which exhibited a remarkable chemical resistance. This study presents a viable approach for developing BPA as hot melt adhesives with desirable performance, which future foster applications in a range of areas.