Environmental Durability of Bio-Based and Synthetic Thermoplastic Composites in Large-Format Additive Manufacturing

Area of Science:

• Materials Science
• Additive Manufacturing
• Polymer Composites

Background:

• Large-format 3D printing enables complex structures using thermoplastic composites.
• Assessing the environmental durability of novel bio-based composites is crucial for their adoption.
• Understanding material degradation under moisture and freeze-thaw is key for structural applications.

Purpose of the Study:

• To evaluate the durability of large-format 3D-printed bio-based thermoplastic composites.
• To compare the performance of wood-fiber/polylactic acid (WF/PLA, WF/aPLA) against conventional carbon-fiber/acrylonitrile butadiene styrene (CF/ABS).
• To quantify changes in moisture absorption and mechanical properties after environmental exposure.

Main Methods:

• Experimental characterization of moisture absorption and coefficient of moisture expansion.
• Assessment of mechanical properties (flexural strength and modulus) before and after accelerated environmental exposure.
• Comparative analysis of three distinct large-format 3D-printed composite systems.

Main Results:

• Bio-based WF/PLA and WF/aPLA composites exhibited higher moisture absorption than CF/ABS.
• Both bio-based composites showed greater reductions in flexural strength and modulus after exposure.
• The environmental susceptibility of large-format 3D-printed bio-based composites was confirmed.

Conclusions:

• Large-format 3D-printed bio-based thermoplastic composites are more vulnerable to moisture and freeze-thaw degradation.
• Conventional CF/ABS demonstrates superior durability under these environmental conditions.
• Further material development is needed to enhance the environmental resistance of bio-based composites for demanding applications.