Understanding the morphology formation and properties of polyamide 6 and bio-based poly(trimethylene terephthalate) blends

The influence of processing conditions on bio-based poly(trimethylene terephthalate) (PTT) and polyamide 6 (PA6) blends via twin-screw extrusion was successfully investigated, bringing new knowledge on the physical interactions between two widely used thermoplastics. A 50/50 wt% blend ratio was selected since it is characteristic of its unpredictable morphology and as such can highlight the behavior of the PTT/PA6 system in general, relevant for all blend ratios. Moreover, those materials are the two most used fibers in carpet industries and this blend presents a possible reality for carpet recycling via melt processing. The effects of the processing conditions on blend morphology were highlighted on the material surface by atomic force microscopy (AFM), and in the bulk by scanning electron microscopy (SEM) after solvent etching of the PA6 phase. The domain size was strongly influenced by the processing temperature used, which was explained by existing theories of blending via measurement of rheology and interfacial tension. The mechanical properties highlighted the interest of controlled morphology through adaptation of the processing parameters for end-product applications. POLYM. ENG. SCI., 58:2210-2218, 2018. (c) 2018 Society of Plastics Engineers