Microstructure of semicrystalline poly(L-lactide)/poly(4-vinylphenol) blends evaluated from SAXS absolute intensity measurement

The semicrystalline morphology of melt-miscible poly(L-lactide) (PLLA)/poly(4-vinylphenol) (PVPh) blends was probed by small-angle X-ray scattering (SAXS) with the measurement of absolute intensity. Blending with PVPh enhanced the SAXS intensity associated with the lamellar stacks. This was attributed to the presence of PVPh in the interlamellar regions that enhanced the electron density contrast (Delta eta) between the crystalline and amorphous layers. The interlamellar morphology was quantitatively characterized by the magnitude of Delta eta deduced from Strobl-Schneider's one-dimensional correlation function assuming the corresponding two-phase model. Good agreement between the measured Delta eta and the values calculated by assuming a complete interlamellar incorporation indicated that nearly all PVPh was expelled into the interlamellar regions upon the crystallization of PLLA.