Additive Manufacturing and Other Techniques for Fabrication of Foams and Electrically Conductive Polymer Composites

  • Author / Creator
    Ostashek, Adam N
  • In this thesis, two aspects of advanced uses for additive manufacturing and microfabrication are investigated: stretchable electronics and polymer foams. These topics were initially part of an extended project effort to develop new capabilities in deformable, high-frequency antennas and the ability to rapidly prototype using combinations of materials that had previously required complex hand assembly. Several methods were investigated in which stretchable electronic devices were fabricated. A horn antenna with a reconfigurable reflector was designed and fabricated using EcoFlex silicone rubber and eutectic gallium indium (eGaIn) to comprise the deformable reflector. A method to produce stretchable electrical wires using an inexpensive consumer-grade fused deposition manufacturing (FDM) 3D printer was developed. Electrically conductive wires, a resistive spiral pressure sensor, and an inductive spiral strain sensor were printed and characterized. Electrical conductivity was achieved in all of the printed devices up to an elongation of 500 %. The utility of foams in this work are that the structural materials reduce their impact on the high frequency performance of electronics, as air has lower inherent losses than solid materials. Foams are also highly useful for lightweight printing applications or in industries like metal casting, where lost foam casting is a common way to produce complex metal parts. The sections of this thesis that discuss foams pertain to applications in functionally graded materials, where the amount of porogen can be varied throughout the thickness of the foam, and applications in the foundry industry. Several foams made from poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS), poly(lactic acid) (PLA), and linear low density polyethylene (LLDPE) were produced and investigated for extensibility and applicability to the lost foam metal casting process. SEBS foams were successfully fabricated via solution casting using widely available, inexpensive soluble templates. A commercially available foaming PLA filament was used to make an expendable pattern for a grey iron casting and the final product was visually characterized. Custom LLDPE filaments containing chemical foaming agents were produced and investigated for their applicability as an alternative material for lost foam patterns.

  • Subjects / Keywords
  • Graduation date
    Spring 2023
  • Type of Item
  • Degree
    Master of Science
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.