Plasticized agarose films: A physicochemical, mechanical and thermal study

Agarose uniquely forms moldable biodegradable films, making it a promising renewable material with exceptional biocompatibility, thermo-reversibility, and flexibility. However, agarose films lose most of their flexibility at low moisture content. One way to assuage this issue is to incorporate plasticizing agents. In this study, four plasticizers (i.e., sucrose, urea, glucose, and glycerol) were chosen and combined in various concentrations and combinations to produce an agarose-based composite. The study examined how four different plasticizers affect agarose's intermolecular interactions, impacting its mechanical, morphological, thermal, and physicochemical properties. Techniques like Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X-ray Scattering, electric actuation, and tensile testing were used to analyze the effects of plasticizers on agarose-based films. The findings reveal that the mechanical and thermal properties of agarose films are influenced to varying degrees by the four plasticizers studied. Plasticizers with high hydroxyl content and smaller molecular size demonstrated the most significant improvements in film flexibility and stretchability. These variations in performance can be attributed to differences in intermolecular interactions, driven by changes in hydrogen bonding groups, as observed through FTIR and X-ray Scattering analyses. A deeper understanding of how hydrogen bonds affect the agarose-plasticizer matrix could pave the way for precisely tailoring the properties of agarose films.