In biodegradable polymer world nanobiocomposites represent a new group of materials filled with inert nanoparticles that shows very interesting properties and the biodegradability of the matrix. In this work we have studied the effect of the polarity of the organomodified montmorillonite and of the elongational flow on the morphology and the rheological and mechanical properties of a new nanobiocomposite with a matrix of biodegradable PLA based blend. The elastic modulus enhances in presence of the nanofiller and this increase is larger and larger with the increment of the orientation. The tensile strength does not show any significant change at the same level of orientation. Moreover, a brittle-to-ductile transition is observed in the anisotropic sample and this effect is again more evident for the nanocomposite. The raise of the interlayer distance is higher for the more polar montmorillonite, even if the two nanocomposites show about the same final interlayer distance and morphology. Some exfoliation is also observed as a result of the application of the elongational flow.