Silane-interfacial toughening of nanocellulose/starch composite films: One-pot engineering for anti-aging food packaging

To enhance the mechanical properties and anti-retrogradation of starch films, employing nanofibrillated cellulose (NFC) as a reinforcing filler is one of the most effective methods. Nevertheless, the dispersibility of NFC in starch matrix and its interfacial compatibility pose significant challenges. In this work, we prepared silane-functionalized NFC through an innovative one-pot strategy, and introduced it into starch matrix by ball-milling treatment. The effects of NFC contents and different silane treatments on the properties of starch-based films were investigated. Notably, the tensile strength, elastic modulus, barrier properties, and hydrophobicity of solution-cast blend films were all improved. Particularly, due to the silane-functionalized NFC exhibits enhanced compatibility and facilitates physical entanglement with starch molecular chains. Starch/KH570-NFC 8 wt% composite films exhibited the highest tensile strength and elastic modulus, increasing from 1.32 MPa to 10.64 MPa and 70.01 MPa to 573.87 MPa, respectively. The mechanisms of interfacial compatibility and mechanical improvements were systematically analyzed. More importantly, the starch film with 8 wt% KH570-NFC exhibited a 29 % tensile strength enhancement after 30 d storage. Furthermore, a fruit preservation experiment demonstrated that the silane-NFC hybrid starch composite film extended the shelf life of strawberries by at least 4 days compared to the control group. These composite films also showcased excellent thermal stability, foldability, and transparency. This study provides an effective way to prepare biodegradable, anti-aging, and enhanced starch-based composite film for food and fruit packaging. • One-pot method was developed for preparing silane-functionalized NFC. • Starch/KH570-NFC8 exhibited excellent tensile strength (10.64 MPa) and elastic modulus (573.87 MPa). • Silane-treated NFC improved aging resistance, water barrier property and thermal stability of starch-based composite film. • Starch/KH570-NFC8 effectively extended the shelf life of strawberries.