How APTMS Acts as a Bridge to Enhance the Compatibility of the Interface between the Hydrophilic Poly(vinyl alcohol) Film and the Hydrophobic Stearic Acid Coating

Abstract

The hydrophobic modification of poly­(vinyl alcohol) (PVA) film as a biodegradable packaging material has received significant attention in recent research. Despite the use of stearic acid (SA) as a coating for the PVA film, a challenge persists due to the poor compatibility between SA and PVA. This study addressed the aforementioned issue by utilizing (3-aminopropyl)­trimethoxysilane (APTMS) as a bridging agent to establish a connection between the hydrophilic PVA film and the hydrophobic SA coating through hydrogen bonding and chemical reactions. First, SEM and EDS analyses confirmed the enhanced interfacial compatibility between the SA coating and the PVA film. Subsequently, the results from 1H NMR, FTIR, and XPS experiments presented evidence of hydrogen bonding and chemical reactions among APTMS, SA, and the PVA film. Interestingly, the PVA-APTMS-SA film demonstrated a contact angle of 120.77°, a water absorption of 7.81%, and a water vapor transmission rate of 8.69 g/m2/h. Furthermore, such a composite film displayed exceptional adhesion performance, requiring detachment stresses of 9.86 ± 0.91 and 6.17 ± 0.75 MPa when tested on glass and marble surfaces, respectively. In conclusion, the PVA-APTMS-SA film exhibited significant potential in extending the freshness of fresh-cut apples, making it a promising eco-friendly packaging material for food preservation.

Comprehensive Evaluation of the Physicochemical Attributes, Antioxidant Capacity, and pH-Responsive Behavior of Starch Films Enhanced by Laver Incorporation

“…WAC, CA, and WVTR are critical parameters influencing the surface hydrophobicity and water vapor permeability of starch films, crucial for determining the quality and shelf-life of food packaging [ 16 , 25 , 26 ]. Hence, understanding and controlling these parameters in starch films is essential for achieving the desired surface water resistance and gas permeability, ultimately impacting the overall efficacy of food packaging and extending the shelf life of packaged food products.…”

“…This reduction was primarily due to the chemical intertwinement and intermolecular interactions between the starch and laver, enhancing the water vapor permeability of the starchbased films [24]. It is noteworthy that the laver film revealed the lowest permeability to water vapor, evident from its WVTR value of 3.29 g/m 2 × h. WAC, CA, and WVTR are critical parameters influencing the surface hydrophobicity and water vapor permeability of starch films, crucial for determining the quality and shelflife of food packaging [16,25,26]. Hence, understanding and controlling these parameters in starch films is essential for achieving the desired surface water resistance and gas permeability, ultimately impacting the overall efficacy of food packaging and extending the shelf life of packaged food products.…”

“…Of the S7-3 film, the S5-5 film and the S3-7 film, the S7-3 film appears to have the greatest potential for use in food packaging applications. It achieved the highest CA value, ranging from 94.77 ± 1.51° to 114.98 ± 1.28°, the lowest WS value, decreasing from 28.65% to 15.38%, and the lowest WVTR value, dropping from 3.06 g/m 2 × h to 2.52 g/m 2 × h. WAC, CA, and WVTR are critical parameters influencing the surface hydrophobicity and water vapor permeability of starch films, crucial for determining the quality and shelflife of food packaging [16,25,26]. Hence, understanding and controlling these parameters in starch films is essential for achieving the desired surface water resistance and gas permeability, ultimately impacting the overall efficacy of food packaging and extending the shelf life of packaged food products.…”