Partially Cured Photopolymer with Gradient Bingham Plastic Behaviors as a Versatile Deformable Material

Area of Science:

• Materials Science
• Polymer Chemistry
• Rheology

Background:

• Oxygen inhibition during ultraviolet (UV) light exposure creates a partially cured layer on photopolymer resins.
• This phenomenon affects the material's mechanical and rheological properties.

Purpose of the Study:

• To investigate the rheological and mechanical behaviors of partially cured photopolymers.
• To characterize the unique properties arising from oxygen inhibition and varying polymerization degrees.
• To explore the potential applications of this material in 3D fabrication.

Main Methods:

• Rheological measurements to determine flow behavior under varying stress.
• Mechanical testing to assess material response.
• Analysis of the photopolymerization gradient induced by oxygen inhibition.

Main Results:

• Partially cured photopolymer exhibits Bingham plastic behavior with a yield stress.
• A deformation rate saturation is observed at higher stresses, defining it as a "gradient Bingham plastic".
• The gradient in polymerization degree is identified as the cause for this unique behavior.

Conclusions:

• The gradient Bingham plastic behavior of partially cured photopolymers is a novel finding.
• This material property offers potential for advanced 3D printing and fabrication of intricate structures.
• Understanding these rheological characteristics is key to harnessing its fabrication capabilities.