Desenvolvimento e caracterização de filmes biodegradáveis de fécula de mandioca modificados com ácido malônico e hipofosfito de sódio

Abstract

This study aimed to synthesize and characterize biodegradable films based on cassava starch modified with malonic acid and sodium hypophosphite, in order to understand the structural, physicochemical, and barrier changes promoted by chemical modification. The films were prepared using the casting technique and subjected to different analyses, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), moisture content determination, water vapor permeability (WVP), and solubility tests in organic and aqueous solvents. FTIR spectra evidenced the incorporation of the modifying agents into the polymer matrix, confirmed by the appearance and intensification of carbonyl (C=O) bands. SEM micrographs revealed homogeneous surfaces with uniform texture and low porosity, especially in samples with higher concentrations of malonic acid. The WVP test demonstrated that the modified films exhibited better water vapor barrier performance compared to the control, while the moisture content analysis indicated that the chemical modification increased the water retention capacity of the polymer matrix. The solubility test revealed high resistance of the films to organic solvents and a characteristic swelling behavior in highly polar solvents, such as DMSO and water, confirming the hydrophilic nature of the material. The results indicate that modification with malonic acid and sodium hypophosphite promoted significant structural changes, enhancing barrier properties and influencing water– polymer interactions without compromising the integrity of the starch matrix.