Structure and properties of bio-based poly(trimethylene terephthalate)/polyamide 56 blends prepared by melt mixing

The extensive use of conventional petroleum-based polymers consumes large amounts of energy and emits a lot of carbon dioxide. Therefore, the development and popularization of bio-based polymer materials are highly significant for ecological reasons. Herein, a series of poly(trimethylene terephthalate)/polyamide 56 (PTT/PA56) blends with different weight ratios were prepared by melt blending of two bio-based polymers, PTT and PA56. The phase structure, miscibility, crystallization and melting behaviors, crystal structure, and mechanical and water absorption properties of PTT/PA56 blend systems were investigated. The results showed that PTT and PA56 were immiscible in the whole range of compositions. The immiscibility of the blend system intensified with the increase of dispersed phase content. As PA56 content increased, tensile strength and elongation at break of samples assumed an increasing trend, whereas impact strength initially remained almost unchanged and then gradually decreased. In contrast, increasing PA56 content gradually increased water absorption of samples. Comprehensive analysis indicated that the best combination of different properties was obtained for the PTT/PA56 blends including 60-80 wt% PA56.