PLA Reinforced with Limestone Waste: A Way to Sustainable Polymer Composites

Area of Science:

• Materials Science
• Sustainable Engineering
• Polymer Composites

Background:

• Industrial stone sludge presents significant disposal challenges.
• Traditional disposal methods are environmentally burdensome.
• Valorizing waste materials is crucial for sustainable practices.

Purpose of the Study:

• To investigate the potential of incorporating stone sludge into polylactic acid (PLA).
• To develop sustainable composite materials from waste stone sludge.
• To evaluate the properties and processability of PLA-stone sludge composites.

Main Methods:

• Melt blending of limestone powder (up to 50% by weight) with PLA using a twin-screw extruder.
• Characterization using Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), and X-ray Diffraction (XRD).
• Thermal stability assessment via Thermogravimetric Analysis (TGA) and mechanical property evaluation (stiffness, impact resistance).

Main Results:

• Uniform distribution of limestone particles within the PLA matrix was confirmed.
• Composites exhibited retained thermal stability and significantly enhanced stiffness (increased elastic modulus).
• Melt flow rate decreased, and brittleness/impact resistance was reduced with higher filler content.

Conclusions:

• Stone sludge can be effectively repurposed as a filler in PLA composites.
• The developed composites offer improved stiffness and thermal stability.
• Successful 3D printing of filaments demonstrates practical applicability.