Comparing the microstructure, topography and surface hydrophilicity of starch polyvinyl alcohol based films containing nanoclay and cellulose nanocrystal

The main objectives of this research were the study and comparing the microstructure of PVA-STNCC and PVA-ST-MMT by X ray diffraction and atomic force microscopy (AFM) and as well as، comparing the effects of two nanoparticle on surface hydrophilicity and moisture absorption. X diffraction patterns showed that microstructure of the PVA-ST-MMT films was exfoliated and PVA-ST-NCC was closer to intercalated structure. The AFM phase images showed good dispersion of nanoparticle in matrix and there wasn’t observed any agglomeration in the phase images of the both films. Comparing the three dimensional topographic images، height distribution point’s curves and roughness parameters showed that MMT produce rougher film in comparison with NCC. Adding MMT and NCC increased the contact angle of film and there isn’t significant difference between MMT and NCC on increasing the contact angle. The water absorption of the films decreased with adding MMT and NCC however، MMT caused higher decrease in comparison to NCC. Comparing the color parameters showed that adding two nano reinforcements didn’t affect the transparency of starch-PVA bionanocomposites however، increased the yellow color of the films.