Homogeneous PVA/sodium lignosulfonate mulch films with improved mechanical and UV/water vapor barrier properties

Homogeneous poly(vinyl alcohol) (PVA)/sodium lignosulfonate (SL) mulch films with good water vapor barrier property, excellent mechanical properties and UV barrier properties were prepared. Effects of SL content on PVA/SL films were investigated by SEM, FTIR, XRD and physical properties, including thickness, density, swelling, water hydrolysis UV/water barrier and mechanical properties. The results illustrated that the films were homogenous and compact, avoiding the aggregation of SL. The integration of SL into PVA matrix dramatically enhanced the properties of mechanical property and UV barrier and water barrier property. The PVA/SL films showed lower swelling ratio in various pH media, lower light transmittance and better biodegradability compared with PVA film. The higher SL content was, the lower swelling ratio and light transmittance, and the stronger UV barrier property of PVA/SL films were. The PVA/SL film with 30 wt% SL addition on PVA basis exhibited the best mechanical properties, including tensile strength of 45 MPa, elongation at break of 307.2% and variable Young's modulus. This work showed a meaningful and simple method to prepare biodegradable functional homogenous films for potential applications of agricultural mulch films.