The effect of processing conditions on the final morphology of Poly(Lactic Acid) (PLA) with bio-based Polyamide 10.10 (PA) 70/30 blends is analyzed in this paper. Two types of PLA were used: Commercial (neat PLA) and a rheologically modified PLA (PLAREx), with higher melt elasticity produced by reactive extrusion. To evaluate the ability of in situ micro-fibrillation (f) of PA phase during blend compounding by twin-screw extrusion, two processing parameters were varied: i) Screw speed rotation (rpm); and ii) take-up velocity, to induce a hot stretching with different Draw Ratios (DR). The potential ability of PA-f in both bio-blends was evaluated by the viscosity (p) and elasticity (k') ratios determined from the rheological tests of pristine polymers. When PLAREx was used, the requirements for PA-f was fulfilled in the shear rate range observed at the extrusion die. Scanning electron microscopy (SEM) observations revealed that, unlike neat PLA, PLAREx promoted PA-f without hot stretching and the aspect ratio increased as DR increased. For neat PLA-based blends, PA-f was promoted during the hot stretching stage. DMTA analysis revealed that the use of PLAREx PLAREx resulted in a better mechanical performance in the rubbery region (T > Tg PLA-phase) due to the PA-f morphology obtained.
Keywords: BioPA10.10; PLA; PLA/PA Bio-blends; in situ MFCs.