The essential formation of this continuous “net-like”-structure of NR phase is not clear at present but this result
might be attributed melt viscosity of PLA being lower than that of NR.
A correlation was proposed by Wu [31] for extruded polymer blends relating the average diameter of the dispersed phase (d) to the viscosity ratio (K) of the dispersed phase to the matrix viscosity (hm), the shear rate (g_ ) and the interfacial tension (a):