Eco-Friendly Biocomposites from Chestnut Waste: Production, Optimization, Characterization, and Application

Area of Science:

• Materials Science
• Sustainable Engineering
• Polymer Science

Background:

• Chestnut waste presents a significant disposal challenge for the Portuguese chestnut industry.
• Valorization of agricultural byproducts is crucial for developing a circular economy.
• Biocomposites offer a sustainable alternative to conventional petroleum-based plastics.

Purpose of the Study:

• To valorize non-commercial chestnut waste into functional biocomposites.
• To optimize the mechanical, thermal, and water resistance properties of chestnut-based composites.
• To explore the potential of natural additives like shellac for enhanced performance.

Main Methods:

• Hot compression molding was used to fabricate the biocomposites.
• A Box-Behnken Design model was employed for process optimization.
• Mechanical testing (flexural strength/modulus), water absorption tests, and thermal conductivity measurements were performed.

Main Results:

• Optimal formulation (70% chestnut, 120 °C, 2.93 MPa, 30 min) yielded Flexural Strength of 9.00 MPa and Flexural Modulus of 950 MPa.
• Shellac coating significantly improved water resistance, reducing water absorption by approximately 50% compared to untreated samples.
• The biocomposite exhibited low thermal conductivity (0.79 W/m·K), classifying it as a thermal insulator.

Conclusions:

• Chestnut waste can be effectively valorized into high-performance biocomposites.
• The developed biocomposites offer a sustainable and eco-friendly alternative to conventional materials.
• Applications such as candle holders demonstrate the practical viability of these novel materials.