Synthesis of Biobased Furan Polyamides with Excellent Mechanical Properties: Effect of Diamine Chain Length

Furan semi-aromatic polyamides have become a biobased substitute for existing petrochemical semi-aromatic polyamides and received more and more attention. In this study, a series of high-performance biobased furan polyamides with different diamine chain lengths (Poly(butylene furanamide) (PA4F), Poly(pentylene furanamide) (PA5F), Poly(hexamethylene furanamide) (PA6F), Poly(octamethylene furanamide) (PA8F) and Poly(dodecamethylene furanamide) (PA12F)) were successfully prepared; Except for PA4F, other resins could be synthesized by one step bulk polymerization. Meanwhile, the effect of diamine chain length was studied. Except for PA4F they were amorphous which was confirmed by IR, XRD and DSC analysis. PA12F to PA5F had high weight-average molecular weights ( M w ) ranging from 34,000 to 65,500 g/mol, number-average molecular weight ( M n ) ranging from 6100 to 26,300 g/mol, glass transition temperature ( T g ) ranging from 89 to 138 ℃ and temperature of decomposition at 5% mass loss ( T d-5% ) from 357 to 408 ℃. The T g of PA4F reached as high as 142 ℃. The tensile strength of PA12F, PA8F and PA5F was obtained for the first time, and reached up to 45, 62 and 84 MPa, respectively. The tensile strength of PA6F was also high at 74 MPa. The α relaxation temperatures of PA12F to PA5F were also high, up to 107, 136, 146 and 158 ℃, respectively.