Research on Shape Memory Properties of PETG Based on 4D-Printed Negative Poisson's Ratio Structures

Area of Science:

• Materials Science
• Additive Manufacturing
• Mechanical Engineering

Background:

• Negative Poisson's ratio (NPR) honeycomb structures exhibit unique mechanical properties.
• 4D printing enables the fabrication of stimuli-responsive materials with complex geometries.
• Shape memory polymers are crucial for developing adaptive and reconfigurable structures.

Purpose of the Study:

• To investigate the shape memory properties of 4D printed re-entrant hexagonal NPR honeycomb structures.
• To compare the performance of polyethylene terephthalate glycol (PETG) and polylactic acid (PLA) in these structures.
• To optimize fabrication parameters for enhanced shape memory behavior.

Main Methods:

• Fabrication of NPR honeycomb structures using 4D printing with PETG and PLA.
• Systematic investigation of structural parameters: wall thickness and unit angle.
• Optimization of process parameters (wall thickness, unit angle, mold pressing angle) using Response Surface Methodology (RSM) and Box-Behnken design.
• Experimental validation of optimized parameters.

Main Results:

• PETG-based structures exhibited significantly better shape memory performance (faster recovery time, higher recovery rate) than PLA.
• RSM optimization identified optimal parameters: 0.5 mm wall thickness, 65° unit angle, and 135° mold pressing angle.
• Experimental validation confirmed high consistency between predicted and actual shape memory outcomes.

Conclusions:

• Structural parameters significantly influence the shape memory behavior of NPR honeycomb systems.
• PETG is a highly suitable material for 4D printed intelligent structures due to its superior shape memory properties.
• The study provides valuable parameter guidance for applying PETG in advanced applications like soft robotics, aerospace, and biomedical devices.