Antibacterial, Antioxidant, and UV-Protective Polymeric Films Based on Poly(vinyl alcohol) Modified with Natural 4-Hydroxybanzylaldehyde Aromatic Aldehyde and Its Derivatives

Polymeric films have been applied in many fields, such as industrial processing, energy technology, and biomedical materials due to their easy processing, low price, and tunable properties. Natural aromatic aldehydes are known to exhibit ultraviolet light (UV)-protective, antioxidant, antibacterial, and immunomodulatory effects. Poly(vinyl alcohol) (PVA) modified with natural aromatic aldehydes could endow the as-prepared polymeric films exhibiting characteristics of both PVA and aromatic aldehyde. Herein, we use 4-hydroxybanzylaldehyde (HB), vanillin (VA), ethyl vanillin, and syringaldehyde (SY) to synthesize aromatic aldehyde-modified PVA polymers and evaluate the UV-protective, antibacterial, and antioxidant activities of the as-prepared polymeric films. All of the polymeric films prepared from the aromatic aldehyde-modified PVA polymers show the effectiveness of these activities. Among them, the HB-modified PVA one exhibits the best mechanical properties, best bactericidal performance, effective antioxidant activity, and UVB (290–320 nm)/UVC (200–290 nm) resistance. The food preservation of HB-modified PVA polymeric films is further evaluated and demonstrates its bacterial colony-forming units inhibition, food spoilage prevention, and water loss reduction owing to their excellent antibacterial activity, UV protection, antioxidative property, and water retention. This study highlights that the aromatic aldehydes modified PVA polymeric films with an additive value for new applications in various areas.