Microwave assisted improvement in physico-mechanical properties of poly(vinyl alcohol)/poly(ethylene imine)/gelatin blends

Blends of poly (vinyl alcohol) (PVA), poly-N-acyl ethyleneimine (PEI) and gelatin (PVA/ PEI/Gel) in the weight ratios 100/0/2, 95/5/2, 90/10/2, 85/15/2, 80/20/2 and 70/30/2 were prepared by solution casting method. The effects of poly (ethylene imine) component in the blend and microwave irradiation on the mechanical and microstructural properties have been investigated using various techniques along with Positron Annihilation Lifetime Spectroscopy (PALS). We observed tremendous improvement in mechanical properties after microwave irradiation for 60 s in 5 wt% of PEI component blend. These results are supported by the SEM data as well the optical data. The free volume data from positron results showed minimum free volume at 5 wt% of PEI after 60 s of irradiation due to cross linking through hydrogen bond formation and possible estrification among the blend components. These results correlate well the mechanical properties like tensile strength and modulus