3D printing of continuous cotton thread reinforced poly (lactic acid)

Area of Science:

• Materials Science
• Polymer Engineering
• Additive Manufacturing

Background:

• Poly (lactic acid) (PLA) is a biodegradable polymer with growing applications in 3D printing.
• Enhancing PLA's mechanical properties and reducing its cost are key challenges for wider adoption.
• Natural fibers offer a sustainable and cost-effective reinforcement solution for polymer composites.

Purpose of the Study:

• To prepare poly (lactic acid)/continuous cotton thread (PLA/CCT) filaments using a prepreg method.
• To investigate the properties of PLA/CCT filaments and their 3D printed composites.
• To evaluate the potential of PLA/CCT composites for 3D printing applications.

Main Methods:

• A custom prepreg device was used to immerse continuous cotton threads (CCT) in molten PLA.
• Filament properties were optimized by controlling dragging speed, tension, immersion temperature, CCT diameter, and alkali treatment.
• Taguchi experiments were employed to determine optimal 3D printing parameters for flexural and impact properties.

Main Results:

• PLA/CCT filaments with a standard 1.75 mm diameter were successfully produced.
• Increasing CCT diameter and alkali treatment significantly improved filament tensile strength and interfacial compatibility.
• 3D printed PLA/CCT composites exhibited enhanced flexural strength (135 MPa) and a 5.5-fold increase in impact strength (18.87 J/mm²).
• Thermal analysis confirmed no degradation of PLA during processing.

Conclusions:

• Continuous cotton thread effectively reinforces poly (lactic acid), enhancing mechanical properties.
• Alkali treatment of CCT improves interfacial adhesion between PLA and CCT.
• PLA/CCT composites demonstrate significant improvements in flexural and impact strength, making them suitable for 3D printing lightweight parts.
• This approach offers a cost-effective and sustainable alternative to pure PLA for additive manufacturing.