Development and characterization of biodegradable chitosan/guar gum polymeric composite films reinforced with alkali pretreated ramie fiber for food packaging applications.

Abstract

The growing environmental concerns associated with synthetic polymer waste have accelerated the search for sustainable packaging materials. This study focuses on the development and characterization of biodegradable composite films based on chitosan and guar gum matrices reinforced with alkali-treated ramie fiber. The biocomposite films were prepared via solution casting, involving homogeneous blend of chitosan (1% w/v) in acetic acid (1% w/v) with Sodium tripolyphosphate (STPP, 0.09% w/v), Guar gum (1.5% w/v) and food-grade glycerol (1.5% w/v) as a plasticizer. To enhance material performance and ensure optimal functionality, the biocomposite film was reinforced with NaOH (3%, 5%, and 7%) pretreated ramie fiber at varying concentrations (0.75-1.5%). The base formulation exhibited a viscosity of ∼250.9 cP and excellent film-forming capacity. Alkali treatment markedly improved fiber-matrix interfacial adhesion with 3% NaOH identified as the optimal condition resulting in enhanced mechanical strength and hydrophobic properties. Among the prepared formulations, the 1% ramie fiber composite (RF-2) demonstrated superior performance with a tensile strength of 9.8 MPa, water contact angle of 108.36° and water vapor permeability of 0.612 ± 0.10 × 10-7 g/m·s·Pa. Thermogravimetric analysis confirmed thermal stability above 300 °C, indicating suitability for packaging applications. Additionally, the films exhibited 19.14% water solubility with controlled biodegradation behavior. The findings established the developed bio-composite film as a promising sustainable alternative to plastic-based food packaging materials.