Development of Novel Composite Core Using Powdered Macadamia Nutshell and Its Sandwich Structures for Building and...

Area of Science:

• Materials Science
• Engineering
• Sustainable Materials

Background:

• Growing demand for sustainable engineering materials due to environmental concerns and fossil fuel depletion.
• Bio-based composites offer eco-friendly alternatives using renewable resources.
• Macadamia nutshells, an agricultural waste, possess desirable properties for structural applications.

Purpose of the Study:

• To develop novel composite cores and sandwich structures using macadamia nutshell particles in an epoxy matrix.
• To investigate the effect of particle size and filler content on mechanical performance.
• To evaluate the potential of macadamia nutshells as a sustainable building material.

Main Methods:

• Fabrication of composite cores using macadamia nutshell particles (10% and 15% weight ratios, two particle sizes) in an epoxy polymer matrix.
• Processing cores into sandwich specimens with carbon fabric skins.
• Mechanical testing including flexural and short beam shear (SBS) tests.

Main Results:

• Composites with higher filler content and finer particles showed up to 15% higher flexural strength and 18% higher stiffness.
• Sandwich structures demonstrated significantly improved interlaminar shear strength (8-15 MPa).
• The 15% fine-particle configuration was identified as the optimal formulation for superior performance.

Conclusions:

• Macadamia nutshell-based composites offer a sustainable pathway for waste utilization and reduced environmental impact.
• These bio-composites show strong potential for structural applications in construction and engineering.
• The study highlights the viability of agricultural by-products in advancing green composites and circular economy principles.