Electrospun PVA membranes reinforced with cellulose nanocrystals and thermally reduced graphene oxide: Thermal, mechanical and UV-protection properties

Abstract

Polyvinyl alcohol (PVA) has been widely proposed as biodegradable films, but it suffers rapid UV degradation affecting mechanical properties, low water resistance and poor antimicrobial properties. To overcome these difficulties, it has been blend with nanocrystalline cellulose (CNC) to produce nanocomposite membranes; however, adding a third element such as reduced graphene oxide (rGO) to the blend with potential packaging applications has not been reported. Herein, CNC was isolated from agroindustrial wastes (sugarcane bagasse; SCB) and used along with thermally reduced graphene oxide (TrGO) to be incorporated into PVA for the production of electrospun membranes for packaging applications. A wide variety of electrospinning parameters were analyzed to obtain PVA:CNC:TrGO composite membranes and their effects on thermal stability, mechanical properties, UV protection and moisture absorption, were evaluated. The results show that the isolation of CNC from SCB presented two phases: monoclinic and triclinic of type I cellulose. The highest crystallinity index (78.96%) and the diameter (10–20 nm)-length (150–200 nm) relation were found at 50 °C using a fiber:acid solution ratio of 1:50. In the case of ternary composite membranes, only free-defect morphologies with a composition of 84.5:15.0:0.5 wt% (PVA:CNC:TrGO) were observed. As a result of the adequate orientation and dispersion of the CNC:TrGO in the PVA matrix an improved was observed in the thermal stability, mechanical (137.48 MPa, HIT), UV barrier (up to 6% compared to pure PVA) and moisture absorption (reducing from 4.8% to 0.05%) properties. The eco-friendly structured ternary nanocomposites support the desired properties to produce food packaging materials.