Effect of addition of 1,6-hexanediamine on thermal properties and crystallization behaviors of biobased PA10T polyamides

Bio-based semi-aromatic poly (decamethylene terephthalamide) acid (PA10T) and a series of poly (decamethylene terephthalamide/hexamethylene terephthalamide) (PA10T/6 T) were synthesized by an efficient one-pot melt polymerization reaction. The chemical structures of the obtained samples were evaluated by fourier infrared spectroscopy (FT-IR). And the influence of addition of 1,6-hexanediamine (HAD) for copolyamides PA10T/6 T on melting points, thermal behaviors, crystallization performances, and mechanical characteristics of PA10T and PA10T/6 T were also analyzed thoroughly. The thermal analysis demonstrates that PA10T/6 T possess excellent thermal stability, and the melting temperatures can be tuned effectively by adding a suitable copolymerization content of the third monomer HAD to improve the processing properties appropriately. POM and XRD were used to research the crystallization behaviors showing that the addition of HAD did not alter the crystalline structure of PA10T essentially. Mechanical properties such as bending modulus and tensile strength of PA10T/6 T remarkably improved with increased HAD content. Moreover, this work provides an approach for preparing plant-derived semi-aromatic copolyamides PA10T/6 T, and these copolyamides exhibit outstanding processing performances, wider processing temperature range, high thermal stability, adjustable mechanical characteristics, and excellent comprehensive properties.