Influence of Glutaraldehyde on the Properties of Agar-Based Films

Abstract

Biopolymers have been used as alternatives to fossil-derived polymers. In this context, agar, a polysaccharide extracted from seaweed, has stood out due to its properties in the formulation of polymeric films. In this work, agar was used in combination with glycerol and glutaraldehyde to formulate polymeric films by the casting method with water as solvent. The films produced were characterized regarding their water interactions using swelling, solubility, and contact angle tests. Mechanical and physical properties were determined using a tensile test and thickness measurements. Optical microscopy was used to analyze the surface, and scanning electron microscopy was used to analyze the surface and cross-section of the films. Spectroscopic properties were obtained by Fourier-transform infrared spectroscopy (FTIR) and ultraviolet–visible spectroscopy. Thermal degradation was determined by thermogravimetric analysis (TGA). It was possible to produce polymeric films with a thickness of around 120 μm and mechanical properties like those found on low-density polyethylene, showing tensile strengths of 15–16 MPa. The solubility of the material was 42% and the swelling ranged between 349–555%, depending on the concentration of glutaraldehyde added to the film formulation of films. Adding glutaraldehyde altered the surface characteristics of the films while maintaining the other properties. However, no evidence of cross-linking reactions was found.