Structure–Property Relationships in Gelatine‐Based Systems Reinforced With Cotton Cellulose Nanocrystals: Toward Bio‐Based Coating Applications

ABSTRACT

This study investigates structure–property relationships in gelatine‐based systems reinforced with cotton cellulose nanocrystals (CNCCs, 0%–20% v/v), using solvent‐cast films as model platforms for the design of bio‐based coating formulations. Unlike previous studies that focus on isolated property improvements, this work establishes a systematic correlation between nanocrystal content, structural organization and functional performance. Materials were characterized using FTIR‐ATR, X‐ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), UV–Vis spectroscopy, mechanical testing and water vapour permeability (WVP). The incorporation of CNCCs promoted intermolecular interactions with the gelatine matrix, leading to increased crystallinity and structural organization, as confirmed by FTIR and XRD analyses. Mechanical properties improved significantly, with tensile strength and elastic modulus increasing progressively, accompanied by reduced elongation at break. A gradual reduction in WVP was observed with increasing CNCCs content, although overall barrier performance remained limited due to the intrinsic hydrophilicity of the system. In addition, the films exhibited enhanced attenuation of UV radiation while maintaining high transparency in the visible range. These findings provide fundamental insights into the role of nanocellulose in modulating gelatine‐based systems and support their potential application as functional coatings in sustainable packaging, where structure‐dependent properties can be tailored according to specific requirements.