Effect of UV irradiation on optical, mechanical and microstructural properties of PVA/NaAlg blends

• PVA/NaAlg blend films with 60:40 wt% were prepared and irradiated with UV light.
• FTIR, FT-Raman, and UV–vis results show the chemical interaction.
• DSC results show a single Tg and TG results show thermal stability up to 250 °C.
• Young׳s modulus, tensile strength and stiffness increase up to 48 h UV irradiation.

Poly(vinyl alcohol) (PVA)/Sodium alginate (NaAlg) blend films with 60:40 wt% were prepared by solution casting method and subjected to UV irradiation for different intervals of time. The optical, mechanical and morphological properties of the blend films were modified after UV irradiation. The FTIR and FT-Raman results show the chemical interaction between PVA and NaAlg. The UV–vis absorption peak at 278 nm shifts slightly towards longer wavelength and the absorption increases with irradiation time, indicate the increase in crosslinking network. The XRD results show an increase in amorphous nature with increase in UV irradiation time. The DSC/TGA results show a single glass transition temperature (Tg), which confirm that the blends are completely miscible and thermally stable up to 250 °C. The Young׳s modulus, tensile strength and stiffness of the blend films increase with increase in UV irradiation time. The SEM images confirm that the surface of 48 h UV irradiated PVA:NaAlg blend is more photo-resistant than unirradiated blend.