Accelerating Degradable Composite Breakdown Using Citrus Processing Side Streams

Daily, vast amounts of waste are produced in the orange juice industry, a large part of which is reused in low-added-value products. In this work, orange vesicle fiber residues from the juice sieving stage were plasticized by extrusion, producing a thermoplastic citrus pulp (TCP). This pulp was incorporated into poly(butylene succinate) (PBS) at up to 50 wt %. The influence of TCP on the molar mass, morphology, tensile properties, rheological behavior, and biodeterioration of PBS in soil was evaluated. Highly flexible compounds with elongations similar to those of PBS were produced. Scanning electron microscopy analyses suggested good dispersion between the TCP and PBS phases, verified after acid extraction of pectin. Rheological analyses indicated the presence of strong interactions in the interconnected network formed by pectin gel, percolation of TCP lignocellulosic fibers, or both. Analyses of mass loss by burial in soil showed that the higher the TCP content in PBS is, the higher and faster the biodeterioration is. Size exclusion chromatography analyses indicated that the greater the concentration of TCP and the better dispersed it was in the compounds, the lower molar masses populations appeared in PBS, indicating higher rates of degradation of PBS in the presence of TCP. This innovative approach not only reuses the waste produced in the orange juice industry but also demonstrates the potential for obtaining environmentally friendly compounds.