Analysis of mechanical behavior of composite materials reinforced by mandarin peel

Mandarin peel (MP) filler is considered as an agricultural waste that can be used as a reinforcement for polymers. HDPE-based hybrid composites were developed using mandarin peel and starch fillers at a total weight content of 30% (HDPE/MP, HDPE/Starch, HDPE/MP/Starch) in order to study the effect of hybridization on mechanical, physical, morphological and biodegradation properties. The different composites developed were initially kneaded in a calendar before preparing the different samples with an average thickness of 2 and 3 mm by compression at 177°C. The mechanical results showed that the combination of mandarin peel/starch fillers has a positive effect compared to composites prepared without hybridization. The incorporation of plant-based fillers into the HDPE matrix increases hardness and Young’s modulus but reduces impact strength, tensile stress, and elongation at break. The addition of fillers also significantly decreases composite density, with hybrid composites exhibiting the lowest values. Interestingly, the water absorption test shows an increase in water absorption rate accompanied by the increase in tangerine peel loading rate and also compared to the composites without hybridization. All composites show a similar water absorption trend, although starch-filled composites absorb less water than those reinforced with mandarin peel. Biodegradation tests indicate that starch-filled HDPE composites degrade more slowly than composites containing mandarin peel.