Opuntia ficus‐indica fruit by‐products as fillers for PLA ‐based biocomposites: A comparison between glochids and peel

Abstract This work explores sustainable and innovative solutions for valorizing by‐products from Opuntia ficus‐indica (cactus pear), a fruit widely grown in Sicily, the world's second‐largest producer. The peel and glochids of cactus pears were used for the first time as fillers in a polylactic acid (PLA) matrix to develop biocomposites. The composites were prepared by incorporating 10% and 20% of peel and glochids separately into PLA using the melt compounding technique. Comprehensive characterization was performed, including morphology, rheology, tensile properties, dynamic‐mechanical behavior, calorimetric response, and wettability. The results demonstrated that incorporating 20% glochids led to a 70% increase in storage modulus (E') at 25 °C compared to neat PLA, significantly enhancing stiffness, while peel‐reinforced composites exhibited a lower but still notable increase of 39%. Rheological tests revealed distinct behaviors: glochid‐reinforced composites exhibited an increase in complex viscosity, whereas peel‐reinforced composites showed a reduction. This was linked to a significant reduction, approximately 50%, in the molecular weight of PLA in the presence of peel. This study highlights the potential of cactus pear by‐products as sustainable fillers for biocomposites, offering a pathway to reduce agricultural waste while enhancing material performance. Highlights Cactus pear by‐products (glochids, peel) used as novel fillers in PLA biocomposites. Glochid fillers enhance PLA stiffness, with effects increasing with filler content. Glochid‐reinforced composites show increased viscosity; peel fillers reduce viscosity. Peel reinforcement leads to matrix degradation, unlike stable glochid composites.