Enhanced mechanical and thermal properties of poly (vinyl alcohol)/corn starch blends by nanoclay intercalation

Poly (vinyl alcohol) (PVA)/corn starch blend films with enhanced properties were fabricated by melt processing and montmorillonite (MMT) reinforcing. It was revealed that strong hydrogen bonding occurred between the abundant OH groups of the matrix and polar SiOSi and OH groups of MMT. The highly exfoliated MMT nanolayers were randomly dispersed in the matrix containing MMT lower than 10 wt%, whereas the intercalated structure was predominant with MMT content higher than 10 wt%. With the increase of MMT, the glass transition temperature as well as equilibrium torque increased. The water sorption decreased and water resistant properties were improved with the incorporation of MMT due to the restricted swelling of the matrix by MMT nanolayers. Significant improvement in strength and flexibility were observed due to the fine dispersion of the MMT layers and the strong interaction between MMT and the matrix. The thermal stability was also improved. The MMT nanolayers could act as the heat and mass transport barriers and retard the thermal decomposition of the composites.