Investigation of nano-size montmorillonite on enhancing polyvinyl alcohol-starch blends prepared via solution cast approach

It was found that the addition of montmorillonite (MMT) at low amount (<5 phr) exhibited reinforcing effect in neat PVOH, whereas higher amount can cause agglomeration leading to decrease of mechanical strength. Nevertheless, such inferior effect is not observed when MMT added in 50% PVOH-starch blends with the tensile strength increased in relation to the amount of MMT added. Besides, higher enthalpy of melting was detected in MMT added PVOH-starch blends via differential scanning calorimetry. This indicates that addition of MMT in PVOH-starch blend showed favorable molecular bonding interactions. From the morphology analysis, PVOH and starch seemed to interact in homogenous condition through the exfoliation of MMT as observed. It was also found that the infrared wavenumber of the hydroxyl group for both neat PVOH and 50% PVOH-starch samples reduced gradually with the increasing amount of MMT. The addition of MMT has shown the “red shift” effect indicating the formation of hydrogen bonding induced by MMT. In conclusion, the blending of MMT in both PVOH and PVOH-starch are favorable to produce superior properties of the resulting blends.