Upcycling Orange-Based Waste into Functional CNCs for Greener L-Lactide Ring-Opening Polymerization

Area of Science:

• Materials Science
• Green Chemistry
• Biotechnology

Background:

• Orange peel waste is an abundant, underutilized resource.
• Cellulose nanocrystals (CNCs) offer unique properties for advanced material applications.
• Sustainable production methods for CNCs are in high demand.

Purpose of the Study:

• To valorize orange peel waste into cellulose nanocrystals (CNCs).
• To investigate the effect of different inorganic acids on CNC properties.
• To evaluate the performance of CNCs as co-initiators in polylactide synthesis.

Main Methods:

• Compositional analysis of orange peel.
• Alkaline/peroxide treatment followed by acid hydrolysis for CNC isolation.
• Comparison of sulfuric, phosphoric, and hydrochloric acids for hydrolysis.
• Characterization of CNC morphology and properties.
• Lactide ring-opening polymerization using CNCs as co-initiators.

Main Results:

• Orange peel contains up to 10.0% cellulose.
• Sulfuric acid hydrolysis yielded CNCs with the highest crystallinity index (0.86).
• Sulfate/phosphate groups influenced thermal degradation and residue content.
• CNCs acted as effective co-initiators in polylactide synthesis, affecting molecular weights.

Conclusions:

• Orange peel waste is a viable feedstock for sustainable CNC production.
• The choice of acid impacts CNC properties and performance.
• CNCs derived from orange peel waste show promise for polyester synthesis.