Preparation and properties of antibacterial PVA@MCC composite membrane assisted by ionic liquids and DMSO

The composite membrane of microcrystalline cellulose (MCC) with polyvinyl alcohol (PVA) was effectively synthesized using ionic liquids (ILs) as the solvent and dimethyl sulfone (DMSO) as the co-solvent through the phase conversion method. The effects of IL structure and the IL/DMSO mass ratio on the solubility of MCC were investigated. The findings indicated that the composite solvent functioned as a non-derivative solvent for MCC dissolution. The inclusion of DMSO decreased the viscosity of ILs and enhanced the rate of MCC dissolution. The solubility of MCC reached 14.5% (mass) when the mass ratio of [Bmim]Cl to DMSO was 1:1. The fabricated MCC membrane exhibited a smooth surface and a dense structure. PVA@MCC demonstrated exceptional mechanical properties and a uniform structure at a mass ratio of 2:1, with an elongation at break of 76% and a tensile strength of 14.6 MPa. The effects of antibacterial agents on the morphology, transmittance, mechanical properties, and antibacterial efficiency of PVA@MCC were investigated. The findings revealed that PVA@MCC fortified with clove oil showcased a flat and smooth surface, devoid of stratification or aggregation, and demonstrated superior mechanical properties compared to its counterparts with chitosan and ZnO additions. The elongation at break of PVA@MCC with clove oil increased to 137.6%, while its tensile strength decreased to 10.4 MPa. PVA@MCC with clove oil exhibited an antibacterial efficiency exceeding 68% against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, thereby extending the shelf life of cherry tomatoes by an additional four days at ambient temperature.